FRANZCO Fred K Chen

MA Praveen J Patel

MRCOphth Gurmit S Uppal

MD Adnan Tufail

PhD Peter J Coffey

MA Lyndon Da Cruz

PhD FRACO Frcophth

Long-term outcomes following full macular translocation surgery in neovascular agerelated macular degeneration

Keywords: Age-related macular degeneration, macular translocation surgery, optical coherence tomography, fundus autofluorescence, choroidal neovascularisation, anti-VEGF therapy

Background/aims: Long-term data of macular translocation for choroidal neovascularisation (CNV) secondary to age-related macular degeneration is lacking. Therefore, we describe the 3-year acuity outcomes.

Methods: This is a retrospective, interventional case series consisting of 40 consecutive patients who underwent translocation between 2003 and 2008. Best-corrected visual acuity (BCVA) at the most recent follow-up visit was compared to that of the 1 year and pre-operative visits. Delayed post-operative complications were recorded, as diagnosed by clinical examination, spectral-domain optical coherence tomography, fundus autofluorescence imaging and angiography.

Results:

The mean (range) follow-up duration was 37.6 (12.4-67.4) months. Median BCVA were 0.80, 0.70 and 0.78 logMAR at the baseline, 1 year and most recent visits (p = 0.13). A 3-line gain in BCVA was seen in 12 (30%) patients at 1 year and 10 (25%) patients at the last observation.

Twenty-seven (68%) patients achieved a BCVA of 6/60 or better and 6 (15%) patients, 6/12 or better at the final visit. In the subset of the cohort followed for 2 or more years, 24 of 32 patients (75%) achieved a BCVA of 6/60 at 1 year but 6 of these (25%) lost 2-lines of BCVA thereafter due to recurrent CNV, idiopathic macular oedema, macular hole or macular pucker. Recurrent CNV developed in 9 patients (23%) within the first 2 years and their final mean VA was 6/30.

Conclusions:

With close post-operative monitoring and early treatment of delayed complications, 25% of this cohort maintained a 3-line gain in acuity at 3 years after macular translocation. 17/12/2009

INTRODUCTION

Neovascular age-related macular degeneration (AMD) is characterised by the formation of choroidal neovascularisation (CNV). In this process, the new vessels may leak or bleed resulting in serous or hemorrhagic pigment epithelial detachment (PED), retinal pigment epithelium (RPE) rip, formation of subretinal fluid and hemorrhage, macular edema and ultimately, disciform scar with chorioretinal atrophy. In those with more than 50% of the lesions being CNV, intravitreal ranibizumab has been shown to reverse visual loss with an average of between 1 to 2-line gain in best-corrected visual acuity (BCVA) and up to 40% of eyes gaining 3 lines of acuity at 12 months which was maintained at 24 months. [START_REF] Brown | Ranibizumab versus verteporfin for neovascular age-related macular degeneration[END_REF][START_REF] Brown | Ranibizumab versus verteporfin photodynamic therapy for neovascular age-related macular degeneration: Two-year results of the ANCHOR study[END_REF] However, the use of these agents in patients with large submacular hemorrhage, serous or hemorrhagic PED and RPE rip remains controversial. [START_REF] Stifter | Intravitreal bevacizumab therapy for neovascular age-related macular degeneration with large submacular hemorrhage[END_REF][START_REF] Meyer | Combined treatment of acute subretinal haemorrhages with intravitreal recombined tissue plasminogen activator, expansile gas and bevacizumab: a retrospective pilot study[END_REF] Although surgical removal of submacular hemorrhage or CNV alone did not restore vision in large randomized trials, [START_REF] Hawkins | Surgery for subfoveal choroidal neovascularization in age-related macular degeneration: ophthalmic findings: SST report no. 11[END_REF][START_REF] Bressler | Surgery for hemorrhagic choroidal neovascular lesions of age-related macular degeneration: ophthalmic findings: SST report no. 13[END_REF] macular translocation surgery, which reconstructs the RPE defect that accompany removal of CNV and blood, has been shown to rescue visual acuity and reading ability with up to a 2-line gain in VA and 40% gaining 3 lines of VA at 1 year in several case series and one pilot randomised trial. [START_REF] Eckardt | Macular rotation with and without counter-rotation of the globe in patients with age-related macular degeneration[END_REF][START_REF] Toth | Macular translocation with 360-degree peripheral retinectomy impact of technique and surgical experience on visual outcomes[END_REF][START_REF] Aisenbrey | Macular translocation with 360 degrees retinotomy for exudative age-related macular degeneration[END_REF][START_REF] Pertile | Macular translocation with 360 degree retinotomy for management of age-related macular degeneration with subfoveal choroidal neovascularization[END_REF][START_REF] Lappas | One year follow up of macular translocation with 360 degree retinotomy in patients with age related macular degeneration[END_REF][START_REF] Wong | Case selection in macular relocation surgery for age related macular degeneration[END_REF][START_REF] Mruthyunjaya | Change in visual function after macular translocation with 360 degrees retinectomy for neovascular age-related macular degeneration[END_REF][START_REF] Uppal | New algorithm for assessing patient suitability for macular translocation surgery[END_REF][START_REF] Gelisken | Full macular translocation versus photodynamic therapy with verteporfin in the treatment of neovascular age-related macular degeneration: 1-year results of a prospective, controlled, randomised pilot trial (FMT-PDT)[END_REF] The aim of macular translocation in AMD is to reposition the macula onto a healthier RPE and choroid after removal of the CNV and blood which invariably damage the underlying supporting tissues. [START_REF] Grossniklaus | Clinicopathologic features of surgically excised choroidal neovascular membranes[END_REF] The source of the healthier RPE-choroid in translocation is located near the supratemporal vascular arcade (paramacular region, about 10º eccentricity) when the macula is suprarotated 45º around the disc. Since the RPE in this region predominantly interact with rods, it is not known if these RPE can also provide long-term support for macular cone survival and function.

Furthermore, the extrafoveal atrophy created by the removal of CNV and subsequent foveal rotation may expand with time or allow recurrence of CNV to threaten foveal function. [START_REF] Aisenbrey | Long-term follow-up of macular translocation with 360 degrees retinotomy for exudative age-related macular degeneration[END_REF][START_REF] Baer | Recurrent choroidal neovascularization after macular translocation surgery with 360-degree peripheral retinectomy[END_REF] The purpose of this study was therefore to report the long-term acuity and macular structural outcome in a cohort of patients who have undergone translocation surgery and examine the causes for late visual acuity decline.

PATIENTS AND METHODS

Forty patients underwent surgery with the intention of macular translocation between 2003 and 2008 at a single centre. The surgical techniques of macular translocation and counter-rotation surgery are similar to that described by Eckardt and Toth and colleagues. [START_REF] Eckardt | Macular rotation with and without counter-rotation of the globe in patients with age-related macular degeneration[END_REF][START_REF] Toth | Macular translocation with 360-degree peripheral retinectomy impact of technique and surgical experience on visual outcomes[END_REF] All translocation surgeries were performed by a single surgeon (LDC). After the 6 and 12 month evaluations, all patients were routinely followed at 4 to 6 monthly intervals unless complications developed. This study was approved by our Research Governance Committee.

From review of the charts, the baseline demographic features and duration of symptoms were recorded. Pre-operative angiographies were retrieved and graded independently according to the Macular Photocoagulation Study criteria by an experienced observer (PJP). [START_REF] Mps Group | Subfoveal neovascular lesions in age-related macular degeneration. Guidelines for evaluation and treatment in the macular photocoagulation study. Macular Photocoagulation Study Group[END_REF] Intra-and early post-operative courses were noted. The outcomes of repair of post-operative retinal detachments and frequency of post-operative macular pucker were recorded. The primary outcome measure was the change in best-corrected visual acuity (BCVA) of the study eye from the preoperative to 1 year and the most recent follow-up visit. For secondary outcome measure, we examined the causes of significant visual acuity loss (greater than 0.2 logMAR decline) in a subset of patients who achieved a BCVA of 6/60 or better at 1 year and were followed for 2 or more years. This subset was chosen because visual acuity testing in AMD patients with BCVA of less than 6/60 has been shown to be unreliable. As an exploratory analysis, we examined the outcomes of those patients who developed recurrent CNV, idiopathic cystoid macular oedema (CMO) and subfoveal extension of RPE atrophy.

BCVA was measured on the retro-illuminated Early Treatment of Diabetic Retinopathy Study (ETDRS) charts, corrected to 1 m and converted to logarithm minimal angle of resolution (logMAR). Post-operative complications were assessed by clinical examinations, fundus autofluorescence imaging, optical coherence tomography (OCT) and fundus angiographies. Retinal imaging was performed at least once post-operatively in all patients at around 12 months and then repeated in selected patients to clarify clinical findings. OCT was performed using the StratusOCT ™ (Carl Zeiss Meditec, Inc., Dublin, CA, USA). More recently, spectral domain-OCT (SD-OCT): 3D OCT-1000 (Topcon Inc., Tokyo, Japan) and the Spectralis HRA+OCT (Heidelberg Engineering GmbH, Dossenheim, Germany), were used. If fluorescein angiography was unavailable, OCT was examined for the presence of cystic change as a marker of CMO. Fundus autofluorescence was assessed by using a scanning laser ophthalmoscope (SLO) -the Heidelberg Retina Angiograph II (HRA II, Heidelberg Engineering GmbH, Dossenheim, Germany). Presence of small round or oval hyper-autofluorescent lesions at the fovea were used as a marker of CMO. Area of reduced autofluorescence signal not due to masking was interpreted as RPE atrophy.

Data were analysed and graphs were constructed using SPSS for Windows, version 14.0 (SPSS Inc., Chicago, IL, USA). Friedman and Wilcoxon signed ranks tests were used to compare BCVA. A p value of < 0.05 was considered statistically significant. Summary statistics including mean, standard deviation (SD), median, 95% confidence interval and proportions were used to describe the change in BCVA and rates of post-operative complications.

RESULTS

Patient cohort

The mean (range) follow-up duration for the 40 consecutive patients was 37.6 (12.4-67.4) months.

Thirty-two patients (80%) were followed for 24 months or longer, 24 patients (60%) for 36 months or longer and 10 patients (25%) for 48 months or longer. The demographic and clinical features are summarised in Table 1. The overall reduction in the number of cases with predominantly CNV lesions coincided with the availability of anti-VEGF agents (see Table 1). Surgical outcomes and post-operative complications are summarised in Table 2. In the earliest cohort, CNV was not removed in some patients and post-operative PDT was given for residual CNV. However, the majority had complete removal of the CNV/blood/fibrosis complex at the time of surgery.

Overall visual acuity outcomes

Median BCVA were 0.80, 0.70 and 0.78 logMAR at baseline, 1 year and the most recent visit (Friedman Test, p = 0.13, see Table 3). At the last observation, 27 patients (68%) achieved a BCVA of 6/60 or better, 17 patients (43%) achieved 6/30 and 6 patients (15%) 6/12 or better (see Table 3). The mean (SD) improvement in BCVA was 0.06 (0.58) logMAR at 1 year. However, at the last observation, the BCVA declined by a mean (SD) of 0.05 (0.63) logMAR. A 3-line gain in BCVA was seen in 12 (30%) and 10 (25%) patients at 1 year and the most recent follow-up (see Table 4).

Late decline in visual acuity and subgroup analysis

To examine the causes of late decline in BCVA, we analysed a subset of the cohort (32 patients) who had 2 or more years of follow-up. In this subgroup, the median BCVA were 0.80, 0.70 and 0.78 logMAR at baseline, 1 year and 2 year visits respectively (Friedman Test, p = 0.036). There was no significant change between the baseline and the 2 year BCVA (Wilcoxon signed rank test, p = 0.530). Among the 32 patients, 24 (75%) achieved a BCVA of 6/60 or better at 1 year. At the last observation (mean of 43 months), 6 of these (25%) had 2-line decline in BCVA after achieving 6/60 at 12 months. The causes of delayed visual loss in these eyes were recurrent CNV (3 patients), CNV complicated by macular hole (1 patient), isolated CMO complicated by macular hole (1 patient) and macular pucker (1 patient). Recurrent CNV developed in 9 patients; 6 during the first and 3 during the second year (see Table 5, Figures 1 and2). No recurrent CNV was seen after 2 years in the 23 patients who were followed for 3 to 5 years. All CNV recurred at the edge of the previous CNV excision site within the macular region except for 1 patient who had de novo CNV (unrelated to the excision site) nasal to the fovea.

Choroidal neovascularisation

From the onset of CNV, these patients were followed for 7 to 43 (mean of 26) months. Treatment of recurrent CNV was performed in all but one eye using either PDT, anti-VEGF agent, intravitreal triamcinolone or a combination of these measures (see Table 5). The mean BCVA at baseline and the last observation for these 9 patients were 0.59 and 0.73 logMAR, respectively. Structural outcome after anti-VEGF therapy varied from total resolution of the oedema and subretinal fluid to persistent intraretinal cystic change, exudate and haemorrhage despite repeated anti-VEGF agent injections.

Cystoid macular oedema

CMO was observed in 38 patients at some stage post-operatively either on angiography or SD-OCT or both. Twenty-one of these were associated other lesions such as macular pucker (7 patients), residual CNV (3 patients), recurrent CNV (9 patients, see Figure 2), pan-uveitis (1 patient) or residual subretinal perfluorocarbon liquid (1 patient). The remaining 17 had isolated CMO with varying degrees of severity and duration. Twelve of these were only detected on angiography or SD-OCT. These subclinical CMO may resolve within a few months or persist for over 4 years. The remaining 5 patients had clinical cystoid changes. The mean BCVA at baseline and the last observations for these patients were 0.72 and 0.60 logMAR, respectively.

Pigment epithelial atrophy

Based on fundus autofluorescence imaging, 17 patients had no RPE atrophy at the foveal centre. In contrast, 13 patients developed subfoveal RPE atrophy post-operatively, associated with recurrent CNV or expansion of parafoveal atrophy. The median BCVA for these 13 patients declined from 0.83 logMAR at 1 year to 1.07 logMAR at the last observation. However, expansion of RPE atrophy without CNV was not a primary cause of delayed loss of BCVA. Development of de novo geographic atrophy was not observed in any patient.

DISCUSSION

In this series of 40 consecutive patients, we examined the long-term change in visual acuity and its relationship to late post-operative complications. At a mean follow-up of 3 years, 25% of patients still had a 3-line gain in BCVA and the median acuity was maintained at 6/36. However, in 25% of patients achieving 6/60 or better at 1 year, BCVA declined by greater than 2 lines primarily as a result of recurrent CNV.

Our initial 1 year outcomes reported by Uppal et al. were similar to that published previously. [START_REF] Pertile | Macular translocation with 360 degree retinotomy for management of age-related macular degeneration with subfoveal choroidal neovascularization[END_REF][START_REF] Mruthyunjaya | Change in visual function after macular translocation with 360 degrees retinectomy for neovascular age-related macular degeneration[END_REF][START_REF] Gelisken | Full macular translocation versus photodynamic therapy with verteporfin in the treatment of neovascular age-related macular degeneration: 1-year results of a prospective, controlled, randomised pilot trial (FMT-PDT)[END_REF] The current longer follow-up data showed that the mean pre-operative visual acuity can be maintained for at least 3 years. This appears better than the outcomes reported by Aisenbrey and colleagues in a cohort of 90 patients. [START_REF] Aisenbrey | Long-term follow-up of macular translocation with 360 degrees retinotomy for exudative age-related macular degeneration[END_REF] They demonstrated a decline of BCVA (logMAR) from a mean of 1.07 at 1 year to 1.26 at around 3 years with only 17% gaining 3-lines of vision. In contrast, we showed that 25% may still gain 3-lines or more of vision at 3 years. This difference may be explained by the close monitoring in all our patients and the early identification and treatment of recurrent CNV. Despite treatment of late complications, significant lose of vision can still occur after 1 year. Furthermore, a significant proportion of patients developed persistent cystoid macular oedema and progressive subfoveal RPE atrophy during follow-up.

Choroidal neovascularisation

The rate of CNV recurrence following macular translocation ranged from 8 to 36% within 1 to 2 years. [START_REF] Pertile | Macular translocation with 360 degree retinotomy for management of age-related macular degeneration with subfoveal choroidal neovascularization[END_REF][START_REF] Lappas | One year follow up of macular translocation with 360 degree retinotomy in patients with age related macular degeneration[END_REF][START_REF] Mruthyunjaya | Change in visual function after macular translocation with 360 degrees retinectomy for neovascular age-related macular degeneration[END_REF][START_REF] Uppal | New algorithm for assessing patient suitability for macular translocation surgery[END_REF][START_REF] Gelisken | Full macular translocation versus photodynamic therapy with verteporfin in the treatment of neovascular age-related macular degeneration: 1-year results of a prospective, controlled, randomised pilot trial (FMT-PDT)[END_REF][START_REF] Baer | Recurrent choroidal neovascularization after macular translocation surgery with 360-degree peripheral retinectomy[END_REF] In previous case series of translocation, these lesions usually predict poor outcome despite re-excision of the CNV, laser photocoagulation or PDT. We showed that with anti-VEGF therapy, visual acuity in some patients can remain as good as 6/12. Almost all reported cases of recurrent CNV occurred at the foveal edge of the RPE defect created by the CNV excision. Baer et al. postulated that the fovea signals the recurrence of CNV. However, they did not report any case of CNV arising de novo from under the translocated fovea. Our 1 case of de novo occult CNV and a similar case of de novo classic subfoveal CNV described by Pertile et al. are unusual. The rarity of de novo CNV developing at the paramacular RPE under the relocated fovea may be related to the thicker and less porous elastic layer of Bruch's membrane or anti-angiogenic factors produced by the RPE-choroid outside the macular region. [START_REF] Bhutto | Pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF) in aged human choroid and eyes with agerelated macular degeneration[END_REF][START_REF] Semkova | Overexpression of FasL in retinal pigment epithelial cells reduces choroidal neovascularization[END_REF][START_REF] Chong | Decreased thickness and integrity of the macular elastic layer of Bruch's membrane correspond to the distribution of lesions associated with age-related macular degeneration[END_REF] In order to reduce recurrence of CNV, the fovea needs to be rotated as far away from the defect as possible or the submacular defect needs to be reconstructed by using healthier RPE such as those derived from stem cells. [START_REF] Vugler | Elucidating the phenomenon of HESC-derived RPE: anatomy of cell genesis, expansion and retinal transplantation[END_REF] Based on our findings, we recommend close monitoring of the edge of excision site clinically and with SD-OCT

Cystoid macular oedema

We identified 2 groups of patients with post-operative CMO. One group had CMO associated with other lesions such as epiretinal membrane or CNV. The other had isolated idiopathic CMO which tended to be subclinical and may resolve spontaneously or persist for years. This higher rate of posttranslocation isolated CMO compared to the previous study may be related to the use of fluorescein angiography and SD-OCT to detect small cysts which may be missed by time-domain OCT. [START_REF] Terasaki | Morphologic and angiographic assessment of the macula after macular translocation surgery with 360 degrees retinotomy[END_REF] Terasaki and colleagues found a 70% incidence rate of CMO and proposed that VEGF, carried within the translocated fovea and/or produced by the surrounding RPE, may also contribute to persistence perifoveal leakage. However, other mechanisms may also be responsible since we observed persistence of cystoid change in the foveal region despite resolution of leakage from extrafoveal recurrent CNV following anti-VEGF therapy (see Figure 2). Another possible mechanism for the development of chronic CMO is non-specific vascular or RPE decompensation secondary to severe surgical trauma since macular translocation is one of the most invasive vitreoretinal procedures.

Pigment epithelial atrophy

We found that 13 patients had subfoveal RPE atrophy and their BCVA declined between 1 year after translocation and the final visit. Many of these patients had expansion of atrophy at the site of recurrent CNV. Sawa et al. reported a lower frequency (10%) of subfoveal RPE atrophy detected on fundus autofluorescence imaging following translocation for myopic CNV. [START_REF] Sawa | Fundus autofluorescence after full macular translocation surgery for myopic choroidal neovascularization[END_REF] The higher rates of RPE atrophy in our series (using fundus autofluorescence) and that of Aisenbrey et al. (61% on fluorescein angiography) may be related to the older age group (mean of 75 years compared to 60 years) of patients and hence more widespread dysfunction and lesser reserve of the paramacular RPE or a higher rate of recurrent CNV. [START_REF] Aisenbrey | Long-term follow-up of macular translocation with 360 degrees retinotomy for exudative age-related macular degeneration[END_REF][START_REF] Sawa | Fundus autofluorescence after full macular translocation surgery for myopic choroidal neovascularization[END_REF] However, in contrast to the series examined by Aisenbrey and colleagues, we did not find that subfoveal RPE atrophy was a cause of delayed loss of acuity. This may be related their study design and use of angiography rather than fundus autofluorescence imaging.

This study is limited by its retrospective nature, variable follow-up investigations and small sample size. However, the study is unique in that data from all 40 consecutive patients including the learning curves and those with unsuccessful translocations performed at 1 centre by 1 surgeon were analysed. The majority of our patients were closely followed until the most recent visit so that the timing of onset for delayed complications could be identified and treated early. In contrast, Aisenbrey et al. reported the outcomes from several surgeons and their patients were discharged and then called back for the purpose of the study.

In conclusion, macular translocation can maintain visual acuity for 3 years and has the potential to restore acuity by 3-lines in 25% and to the level of 6/12 or better in 15% of the patients. The finding of delayed loss of BCVA after 1 year underlies the importance of examining long-term data on novel surgical techniques. Based on these findings, macular translocation remains a treatment option for patients with second eyes affected by neovascular AMD subtypes which are not suitable for anti-VEGF therapy. We would also recommend close monitoring within the first 2 years after translocation for early detection and treatment of post-operative complications.

17/ 12

 12 /2009 to detect early signs of CNV. Prompt initiation of a course of anti-VEGF therapy can maintain visual acuity gained following translocation.

Figure 1 .

 1 Figure 1. Patient 28 had juxtafoveal and extrafoveal recurrent choroidal neovascularisations (CNV) at 10 months post-translocation. He received 3 intravitreal injections of bevacizumab followed by 12 injections of ranibizumab to maintain a visual acuity of 6/12. (A) Fundus autofluorescence image and (B, C) fluorescein angiography showed recurrence of CNV at 10 months. (D) Fundus autofluorescence image and (E) optical coherence tomography (OCT) scan at 28 months showed expansion of RPE atrophy at the site of recurrence and persistent subfoveal fluid. (F) Fundus autofluorescence image and (G) OCT scan at 36 months showed continued expansion of RPE atrophy at new sites of CNV recurrence and resolution of subfoveal fluid.

Figure 2 .

 2 Figure 2. Patient 18 had extrafoveal recurrent choroidal neovascularisation (CNV) at 12 months posttranslocation associated with cystoid macular oedema. (A) Fundus autofluorescence, (B, C) fluorescein angiography and (D) colour fundus photograph showed new haemorrhage and leak at the supra-nasal border of the excision site and cystoid macular oedema. Six months later (E) fundus autofluorescence, (F, G) fluorescein angiography and (H) colour fundus photograph showed a disciform scar and persistence of CMO despite 3 injections of bevacizumab. Small intraretinal cystic change remained and RPE atrophy progressed despite inactive CNV at (I, M) 24, (J, N) 30, (K, O) 36 and (L, P) 42 months. His visual acuity was maintained at 6/18 for over 3 years.

Table 1 . Demographic data for all patients who underwent translocation surgery Demographics and

 1 PDT, photodynamic therapy; R, right; RPE, retinal pigment epithelium; Rx, treatment. † Predominant lesion (lesions with angiographic evidence of tear of the RPE are categorized under RPE rip regardless of CNV or blood components).

	17/12/2009
	TABLES
		2003-2004	2005	2006	2007-2008	Entire cohort
	Patient
	Characteristics
	Number of patients	10 (3, 7)	12	10	8 (5, 3)	40
	Median age	72.0	77.5	81.5	78.0	76.5
	M:F	2:8	6:6	4:6	4:4	16:24
	R:L	4:6	7:5	5:5	5:3	21:19
	Median (range)	8.5	9.0	7.2	3.3	7.0
	duration of	(4 -32)	(5 -16)	(2 -10)	(2 -6)	(2 -32)
	symptom
	Lesion features †
	RPE rip	1	2	2	2	7
	Blood	3	6	6	6	21
	CNV	6	4	2	0	12
	Median lesion size	7	10	9	20	10
	(range in DA)	(4 -40)	(2 -37)	(3 -41)	(9 -49)	(2 -49)
	Previous Rx for	1 had prior	None	None	None	None
	CNV	PDT x 1
	Median VA	0.89	0.70	0.80	1.14	0.80
	(logMAR)
	% with VA of 6/60	60%	92%	90%	50%	75%
	or better
	CNV, choroidal neovascularisation; DA, disc area; F, female; L, left; logMAR, logarithms of minimum angle of
	resolution; M, male;

Table 3 . Frequency distribution of visual acuity at baseline, 1 year and the final visit

 3

	Visual Acuity	At Baseline	At 1 Year	At Final Visit
			Visual Acuity (logMAR)
	Mean (95% CI)	0.96 (0.80 to 1.12)	0.90 (0.70 to 1.09)	1.01 (0.79 to 1.23)
	Median (min, max)	0.80 (0.18 to 2.28)	0.70 (0.10 to 2.28)	0.78 (0.12 to 2.28)
			No. of Patient (%)
	6/12 or better	1 (2%)	5 (12%)	6 (15%)
	6/30 or better, worse than 6/12	13 (33%)	16 (40%)	11 (28%)
	6/60 or better, worse than 6/30	16 (40%)	8 (20%)	10 (25%)
	Worse than 6/60	10 (25%)	11 (28%)	13 (32%)
	CI, confidence interval; max, maximum; min, minimum.

Table 4 . Frequency distribution of change in visual acuity at 1 year and the final visit.

 4

	Visual Acuity	Baseline to 1 year	1 year to Final	Baseline to Final
		Visual Acuity Change (logMAR)
	Mean (95% CI)	0.06 (-0.12 to 0.25)	-0.11 (-0.20 to -0.02)	-0.05 (-0.25 to 0.15)
	Median (min, max)	0.14 (-1.68 to 1.66)	-0.02 (-1.18 to 0.58)	-0.01 (-1.68 to 1.60)
			No. of Patient (%)
	> 6-line improvement	5 (12.5%)	0 (0%)	5 (12.5%)
	> 3-line to < 6-line improvement	7 (17.5%)	1 (2.5%)	5 (12.5%)
	> 1-line to < 3-line improvement	11 (27.5%)	5 (12.5%)	7 (17.5%)
	< 1-line change	6 (15%)	19 (47.5%)	6 (15%)
	> 1-line to < 3-line deterioration	4 (10%)	5 (12.5%)	4 (10%)
	> 3-line to < 6-line deterioration	3 (7.5%)	8 20%)	8 (20%)
	> 6-line deterioration	4 (10%)	2 (5%)	5 (12.5%)
	CI, confidence interval; max, maximum; min, minimum.

ACKNOWLEDGEMENTS

This work was also supported by funding from The London Project to Cure Blindness and the NIHR Biomedical Research Centre for Ophthalmology. 17 /12/2009

This study is funded by the London Project to Cure Blindness.


MD Concetta Irace
email: irace@unicz.it

Fabio Scarinci

Vincenzo Scorcia

Donatella Bruzzichessi

Raffaella Fiorentino

Giorgio Randazzo

Giovanni Scorcia

Agostino Gnasso

Association between low Whole Blood Viscosity, Hematocrit, Hemoglobin and Diabetic Retinopathy in subjects with type 2 diabetes

Keywords: Whole blood viscosity, hematocrit, hemoglobin, type 2 diabetes, diabetic retinopathy, endothelial function

Introduction

Blood flow velocity and pattern influence vessel tone, structure and function through interaction of blood with the endothelial surface. The characteristics of the blood, i.e. viscosity, hemoglobin concentration and hematocrit strongly influence blood velocity and pattern and, as a consequence, the function and structure of the vessels [START_REF] Cunningham | The role of shear stress in the pathogenesis of atherosclerosis[END_REF].

In vitro experimental models and in vivo studies have demonstrated the association between whole blood viscosity (WBV) and atherosclerosis in some arterial districts [START_REF] Koenig | The possibile role of hemorheology in atherothrombogenesis[END_REF][START_REF] Carallo | Whole blood viscosity and haematocrit are associated with internal carotid atherosclerosis in men[END_REF]. Chronic angina and acute myocardial infarction are significantly influenced by hematocrit, and anemia has been associated with an increased mortality for cardiovascular disease [START_REF] Rainer | Changes in blood rheology in patients with stable angina pectoris as a result of coronary artery disease[END_REF][START_REF] Da Silveira | Association of anemia with clinical outcomes in stable coronary artery disease[END_REF]. While high WBV seems to be involved in the development of atherosclerosis and acute cardiovascular events, few data have been reported on the association between WBV and small vessels disease.

It is well known that diabetic subjects can experience macro-and micro-angiopathy, the latter leading to clinical complications like retinopathy, nephropathy and neuropathy. Actually, diabetic retinopathy (DR) is considered the most important risk factor for blindness in adults and the prevalence of DR increases with age and with diabetes duration. It is estimated that after 20 years of disease more than 60% of type 2 diabetic subjects have some degree of DR [START_REF] Kahn | Ocular complications of diabetes mellitus, in Joslin's Diabetes Mellitus[END_REF]. Large prospective intervention studies have demonstrated that optimal glycemic control reduces the incidence of DR as well as the progression of the disease [7,8]. In spite of this evidence, the mechanisms involved in the pathogenesis of DR are still unknown.

Apart from classical risk factors for DR, hemorheological parameters have also been considered in the pathogenesis of this complication, with conflicting results. The aim of the present study was to verify if blood viscosity, hematocrit, and hemoglobin associate with DR in subjects with type 2 diabetes.

Subjects and Methods

Participants and Measurements: For our aim we selected subjects with type 2 diabetes among outpatients regularly attending our metabolic unit and with a complete laboratory examination and full visit in the last two months. One hundred and ninety-nine diabetic subjects, consented to participate to the study. Males and post-menopause females were included. Menopause was defined as absence of menses for 12 consecutive months. Pre-menopausal females, as well as individuals with elevated urine albumin excretion, measured in 12-hour nocturnal urine, were excluded because of the possible influence of menstruation and impaired renal function on hemorheological parameters. A control group of 95 age and gender matched, non-diabetic subjects were recruited.

They were clinically healthy and had no identified cardiovascular risk factors. The local Ethical Committee (Azienda Ospedaliera Mater Domini) approved the study protocol and the investigations were carried out in accordance with the principles of the Declaration of Helsinki. The protocol included physical examination, blood withdrawal for serum analysis and complete ophthalmologic examination. Physical examination included height and weight measurement, calculation of the body mass index (BMI) and measurement of blood pressure.

Biochemical Analysis: A venous blood sample was withdrawn after 12 hours fasting. Serum glucose was assessed by a modified hexokinase/gluose-6-phosphate dehydrogenase procedure. Cholesterol and triglycerides were measured by enzymatic methods, HDL-cholesterol was measured after dextran-magnesium precipitation, and LDL was calculated according to Friedewald formula.

Fibrinogen measurement was performed by radial immunodiffusion (NOR-Partigen, Behring, Marburg, Germany). The hematocrit level was calculated from the measurement of red blood cells, hemoglobin (Hb) by high-pressure liquid chromatography (HPLC) and plasma proteins by the biuret method. Glycated hemoglobin (HbA 1c ) was estimated by HPLC. Renal function was evaluated by the estimation of glomerular filtration rate (GFR) using the modified Cockroft and hematocrit and plasma protein [START_REF] De Simone | Relation of blood viscosity to demographic and physiologic variables and to cardiovascular risk factors in apparently normal adults[END_REF]: WBV = [0.12 x hematocrit] + [0.17 x (plasma proteins-2.07)] where hematocrit is in % and plasma protein in g/L. The unit for viscosity is the centipoises (cP) corresponding to the ratio of the shear rate of blood to the shear rate of water. The formula has been validated with direct viscosity measurement through a wide range of hematocrit (32-53 %) and plasma protein (5.4-9.5 g/dl) [11].

Cardiovascular risk factors, i.e. hypertension, hyperlipidemia and obesity were defined as follows: hypertension as SBP and/or DBP ≥130/85 mmHg or use of antihypertensive agents; hyperlipidemia as total cholesterol and/or triglycerides >5.1 mmol/L and/or >2.2 mmol/L, respectively or use of hypolipidemic drugs. Smokers included subjects that smoked cigarettes or cigars daily. Subjects were defined as having cardiovascular disease (MI, Stroke, peripheral arterial disease) only if they had a medical record describing the event.

Ophthalmologic examination: During the same day of physical examination and blood withdrawal, all subjects underwent a complete bilateral retinal examination, including fundus photography after mydriasis. Subjects were grouped according to the presence or absence of DR (With DR; Without DR). Retinopathy was graded on the presence of microaneurysms, hemorrhages, hard exudates, area of revascularization, fibrous proliferation and and/or laser scars in the more severely affected eye.

The ETDRS (Early Treatment Diabetic Retinopathy Study) scale was used to define the severity of DR: 1. absence of retinopathy (level 10); 2. minimal non-proliferative diabetic retinopathy (NPDR) (level 20, 35, 43); 3. moderate to severe NPDR and proliferative DR (level ≥ 47) [START_REF]Photocoagulation for diabetic macular edema; ETDRS report no. 1[END_REF].

Statistical analysis:

Values are shown as mean ± SD. Comparisons were performed using Stat View 5.0 for McIntosh. Differences in clinical and biochemical variables between control and diabetic subjects, and between subjects with and without DR, were evaluated using two-tailed t-test for unpaired data. The groups classified according to the severity of DR were compared using ANOVA-test with Bonferroni/Dunn as post-hoc test. Triglycerides and disease duration were not normally distributed; therefore they were log-transformed before applying the parametric tests. The independent association between DR and WBV, Hb, and Hct after adjustment for age, sex, HbA 1c , fibrinogen, disease duration, GFR, cardiovascular risk factors, different antidiabetic treatment, and previous cardiovascular events was evaluated using a logistic regression analysis model.

Results

Characteristics of studied subjects;

The age range of the 190 diabetic subjects was 40-75 years (mean ± SD 59.9±9.0). Among these 111 were males (58%) and 79 females (42%), and the mean disease duration was 11.5 years. One hundred forty were being treated with oral antidiabetic drugs (sulfonylureas and/or insulin sensitizer), 32 were treated with insulin therapy and 18 were using both. Females had higher BMI (32.1±4.3 vs 30.2±4.4 kg/m 2 , p<0.01), total cholesterol (5.1±0.9 vs 4.7±1.1 mmol/L, p<0.01), HDL-cholesterol (1.4±0.4 vs 1.2±0.3 mmol/L, p<0.01) and longer disease duration (13.4±9.5 vs 10.1±8.0 years) compared to males. As far as cardiovascular risk factors is concerned, the prevalence of hypertension and hyperlipidemia was respectively 55 and 66 % in all diabetic subjects, without any significant difference between males and females. No diabetic subjects were currently smokers. Twenty-eight subjects (15%) had a previous acute ischaemic event, and the prevalence was not significantly different between diabetic males and females.

Hypertensive subjects were on treatment with renin-angiotensin system blockers and among these, 35% were on treatment combined with calcium channel blockers. Subjects with a previous acute ischemic event were on treatment with antiplatelet agents. Eighty-eight % of all diabetic subjects were being treated with statins.

The 95 control subjects had lower fasting glycemia, lipids, blood pressure and BMI (Table 1). Mean age of the control subjects was 57.5±9.1 years, and male sex prevalence was 58% (p=NS compared to diabetic subjects). Table 1 shows Fibrinogen, Hb, Hct, and WBV in control and diabetic subjects, according to gender. In both females and males fibrinogen was significantly higher in diabetic subjects compared to controls. Male diabetic subjects had Hb, Hct and WBV comparable to those of control subjects. In contrast, diabetic females had significantly lower hemorheological values compared to both control female and diabetic male subjects.

Associations Between DR, Gender and Hematological Values:

In all diabetic subjects the prevalence of any degree of DR was 39% and the prevalence was higher in females compared with males (52 vs 30 %, p <0.05). Females and males with DR both had a significantly higher fasting glucose and HbA 1c , compared with females and males without DR.

Disease duration was longer only in females with DR. In both sexes Hb, Hct, and WBV were significantly lower in subjects with DR compared to subjects without DR (Table 2).

Associations Between Severity of DR, Gender, and Hematological Values:

Hematological values were compared between the three DR severity groups for each gender. In both sexes, Hb, Hct, and WBV significantly decreased with increasing severity of DR. Fibrinogen increased only in females while it was comparable in the three male groups (Tab 3). Clinical and biochemical variables were not different among males, while among females fasting glycemia (7.7±2.3, 10.3±2.9, 11.8±2.5 mmol/L; p<0.01), HbA 1c (6.5±1.2, 7.9±1.5, 8.3±1.5 %; p<0.01), and disease duration (7.6±6.0, 17.5±9.1, 18.9±2.9 years; p<0.01) progressively increased with increasing DR severity.

Association between DR and hemorheological variables

To evaluate the independent association between Hb-DR, Hct-DR, and WBV-DR, the multiple logistic regression analysis was performed for each variable. In each model the association was assessed after adjustment for age, sex, fasting glycemia, HbA 1c , fibrinogen, disease duration, GFR, cardiovascular risk factors, different antidiabetic treatment, and previous cardiovascular events. As shown in Table 4 all 3 variables were significantly and independently associated with DR. The mean Odds Ratios and the Confidence Intervals were all negative, indicating that higher WBV, Hct, and Hb values associated with a lower risk of DR. The other variables associated with DR were HbA1c, disease duration, and previous cardiovascular events (data not shown).

Discussion

The main finding of the present study is that WBV, Hct, and Hb are lower in diabetic subjects with retinopathy compared to subjects without retinopathy. Furthermore, levels of these hemorheological variables decrease with increasing degree of retinopathy.

The relationship between WBV and DR is quite controversial and the number of reports on this topic is limited. Some studies have reported a positive correlation, suggesting a possible role of increased WBV in the pathogenesis of DR. However, this finding has not been confirmed in other studies [START_REF] Vekasi | Hemorheological alterations in patients with diabetic retinopathy[END_REF][START_REF] Vekasi | Hemorheological factors in hypertensive and diabetic retinopathy[END_REF][START_REF] Turczynski | Correlations between the severity of retinopathy in diabetic patients and whole blood and plasma viscosity[END_REF][START_REF] Pepple | Alteration in hemorheological determinants and glycated hemoglobin in black diabetic patients with retinopathy[END_REF]. In large artery districts, increasing blood viscosity is generally considered potentially dangerous since it affects peripheral vascular tone, increases blood pressure and causes disturbance of coagulation [START_REF] Danesh | Haematocrit, viscosity, erythrocite sedimentation rate: metaanalyses of prospective studies of coronary heart disease[END_REF]. However, there is also evidence that low hematocrit influences negatively the prognosis of subjects with cardiovascular disease [START_REF] Amin | Hematocrit and left ventricular mass: the Framingham Heart Study[END_REF]. A recent published paper of Salazar-Vasquez might explain these conflicting results. He found an U-shaped relationship between Hct and blood pressure, suggesting that both lower and higher Hct values associate with higher mean arterial pressure [START_REF] Salazar-Vazquez | Blood Pressure and Hematocrit in diabetes and the role of endothelial responses in the variability of blood viscosity[END_REF].

Blood viscosity and hematocrit strongly influence shear stress, that is the frictional force exerted by the flowing blood on the endothelial surface. Shear stress, in physiological range, is known to be crucial for normal vascular functioning, which includes the regulation of vascular tone and the synthesis of antiatherogenic substances. Low shear stress, as well as high shear stress, reduces the protective action mediated by endothelium and influences plaque formation (see references nr. 1).

In small vessel districts, shear stress is as well important regulating the synthesis of nitric oxide and controlling vessel tone and angiogenesis in order to adapt the structure to the function [START_REF] Martini | Beneficial effects due to increasing blood and plasma viscosity[END_REF][START_REF] Huo | Capillary perfusion and wall shear stress are restored in the coronary circulation of hypertrophic right ventricle[END_REF]. It is likely that shear stress also influences the function and the activity of retinal microvessels, acting on endothelial cells and pericytes, which are important regulators of vascular remodeling and tone. The dysfunction and the loss of these cells can promote the development or worsening of DR [START_REF] Ruggiero | Involvement of cell-cell interactions in the pathogenesis of diabetic retinopathy[END_REF]. Our findings are consistent with the hypothesis that low hematocrit and WBV, through a reduction in shear stress, foster the development of DR.

These results are in line with those reported in a large prospective study, the ETDRS, aimed to identify the factors responsible for the progression of DR to high-risk proliferative retinopathy. The authors have found decreased Hct and Hb levels associated with increased risk of retinopathy progression. Interestingly, this study has shown an increased risk of disease progression already for Hct values lower than 45 in males and 40 in females [23].

Little attention has been given to anemia as risk factor for the development or worsening of DR.

Small studies have previously demonstrated that the development of severe anemia causes the progression of retinopathy to florid proliferative stage, and the treatment of anemia with erythropoietin improves visual acuity and non-proliferative retinopathy [24,25]. In a more recent cross sectional study of subjects attending a diabetic clinic, it has been found DR to be twice among patients with mild anemia (Hb <12 g/dl) with a prevalence of severe retinopathy significantly higher compared to subjects with DR and Hb >12 g/dl [26]. These results suggest that low Hb levels, even within normal range, might contribute to the development and progression of DR.

There is no clear evidence that anemia per se causes a direct vascular injury, however there is some evidence supporting that anemia may modulate the activity of pathways that lead to progressive organ damage. For instance, hypoxia influences a wide range of mitogenic and fibrogenic effects and modifies the expression of genes involved in angiogenesis and capillary permeability, vasomotor response, glycolysis, matrix metabolism and cell survival. The activity of these pathways can lead to the specific diabetic complications.

Possible mechanisms contributing to the onset of anemia in type 2 diabetes include reduced red cell survival and inhibitory effect of cytokines on erythrocyte stem cells [27,28]. The role of some inflammatory molecules, like fibrinogen, and C-reactive protein on development of DR has been clearly reported in several papers and our data about fibrinogen are confirmatory of this association [29].

The present study has some limitations. First, WBV has not been directly measured but calculated.

However, others have previously demonstrated a very high correlation between measured and calculated viscosity [11]. Second, the present is an observational study that can not be used to define a cause-effect relationship, but can anyway give important information on the association between DR and clinical and biochemical profile of diabetic subjects. Third, the majority of the diabetic subjects investigated had hypertension and hyperlipidemia, whereas none of the controls did. Therefore differences between diabetic and control group might be due to the presence of these vascular risk factors. However, this difference is unlikely to lead to bias in the comparison of the three levels of retinopathy. Finally, based on the findings of our study, an important clinical question arises: should we therapeutically raise the oxygen carrying capacity of blood by treating diabetic patients with anemia and low hematocrit in order to prevent possible ocular complications? Unfortunately, it is currently not possible to give an answer to this question and probably doubleblind randomized clinical trials are needed to clarify this point.

In conclusion the present study demonstrates a clear inverse association between WBV, Hb, Hct, and DR, both proliferative and non-proliferative, in subjects with type 2 diabetes and without overt nephropathy, supporting the hypothesis that hemorheological variables play an important role in the development of DR. While further studies are needed to clarify through which mechanisms WBV influences DR, the finding that WBV, Hb and Hct are reduced in subjects with DR should drive the accomplishment of intervention studies to verify whether the correction of these alterations can represent a valid therapeutic approach to prevent DR beyond the strict control of glycemia.


MD, PhD Tryfon Rotsos

MB Mandeep S Sagoo
email: mandeep.sagoo@moorfields.nhs.uk

PhD, MRCOphth, FRCS Lyndon Dacruz

PhD, MRCOphth Richard Andrews

PhD, FRCOphth Jonathan Dowler

INTRAVITREAL ANTI-VEGF TREATMENT IN EYES WITH COMBINED CHOROIDAL NEOVASCULARISATION AND VITREOMACULAR TRACTION SYNDROME

Keywords:

Purpose: To report the effect of intravitreal anti VEGF injections (IVI) on visual acuity (VA) in eyes with choroidal neovascularisation (CNVM) and coexistent vitreomacular traction (VMT) or when VMT has developed during the course of treatment.

Methods:

Retrospective interventional case series of 7 eyes in 7 patients. VMT was monitored with serial optical coherence tomography scans.

Results:

The mean age at presentation was 74 years (range 64-95 years). All patients presented with blurring of central vision, rather than distortion. The aetiology of the CNVM was wet age-related macular degeneration in 5 eyes (72%), angioid streaks in 1 eye (14%) and pathological myopia in 1 eye (14%). Ranibizumab was used in 4 eyes (57%) and bevacizumab in 3 (43%) for the active CNVM component. The mean follow-up was 11 months (range 2-28 months). None of the eyes in this series required surgery for the VMT component, nor were there any cases of spontaneous resolution of VMT.

Visual acuity was stabilized or improved in 5 of the 7 eyes (71%) with IVI. Visual acuity results across the whole group were gain of 3 or more lines of Snellen visual acuity in 2 eyes (28%), gain of up to 3 lines in 3 eyes (42%), no change in visual acuity in 1 eye (14%) and loss of up to 3 lines in 1 eye (14%). There were no eyes losing more than 3 lines of Snellen visual acuity. In 4 eyes with pre-existing VMT, VA improved in 3 with IVI. In 3 eyes that developed VMT after IVI, VA improved in 2 with IVI. Delay from diagnosis of CNVM to treatment with IVI contributed to a poor response.

Conclusions:

Most eyes improved VA with IVI for combined CNVM and VMT. Despite the often dramatic features of VMT on optical coherence tomography, treatment of co-existing CNVM should be prompt. Vitreoretinal surgery was not required in this series, but is held in reserve if there is still potential for gain in vision following CNVM resolution.

INTRODUCTION

Vitreomacular traction syndrome (VMT) is a distinct clinical entity of abnormal relation between the central retina and the posterior hyaloid face, which can lead to loss of visual acuity and distortion of vision. [START_REF] Reese | Vitreomacular traction syndrome confirmed histologically[END_REF][START_REF] Hikichi | Course of vitreomacular traction syndrome[END_REF][START_REF] Margherio | Surgical management of vitreomacular traction syndromes[END_REF] With the use of optical coherence tomography this condition is much more readily recognized, with antero-posterior traction of the posterior hyaloid on the central retina, distorting macular anatomy. [START_REF] Massin | Optical coherence tomography for evaluating diabetic macular edema before and after vitrectomy[END_REF][START_REF] Schmidt-Erfurth | Three-dimensional ultrahigh-resolution optical coherence tomography of macular diseases[END_REF][START_REF] Maftouhi | Anomalous vitreoretinal adhesions in patients with exudative age-related macular degeneration: an OCT study[END_REF] Choroidal neovascularisation (CNVM), from a variety of aetiological causes, results in an exudative disturbance of the macular anatomy, leading to similar symptoms as VMT. [START_REF] Bird | An international classification and grading system for age-related maculopathy and age-related macular degeneration. The International ARM Epidemiological Study Group[END_REF] Occasionally the situation occurs where the two conditions co-exist, and one may precede the onset of the other. [START_REF] Mojana | The role of abnormal vitreomacular adhesion in agerelated macular degeneration: spectral optical coherence tomography and surgical results[END_REF][START_REF] Krebs | Posterior vitreomacular adhesion: a potential risk factor for exudative age-related macular degeneration?[END_REF] Recently, the mainstay of treatment for CNVM has become the use of intravitreal injections of agents that neutralize vascular endothelial growth factor (VEGF), such as pegaptanib, ranibizumab or bevacizumab (IVI). [START_REF] Gragoudas | Pegaptanib for neovascular age-related macular degeneration[END_REF][START_REF] Rosenfeld | Ranibizumab for neovascular age-related macular degeneration[END_REF][START_REF] Brown | Ranibizumab versus verteporfin for neovascular age-related macular degeneration[END_REF][START_REF] Giansanti | Intravitreal bevacizumab therapy for choroidal neovascularization secondary to age-related macular degeneration: 6-month results of an open-label uncontrolled clinical study[END_REF] However, little attention has been paid in the literature to the management of eyes in which both CNVM and VMT co-exist.

In the present study, we report our experience in a series of 7 patients treated for choroidal neovascularisation, who had either the onset or worsening of VMT after the start of antiVEGF injections.

METHODS

A retrospective descriptive interventional case series of eyes with VMT and co-existing CNVM was carried out. For the purpose of this study, data were collected on the patient demographics, ocular co-morbidity, fluorescein angiographic features of the CNVM, aetiology of the CNVM, timing of onset or worsening of VMT in relation to the CNVM, optical coherence tomography (OCT) features and treatment details of eyes in this series. Supplemental angiography with indocyanine green was performed only if there was insufficient information on the fluorescein angiography to make a definitive angiographic diagnosis.

Optical coherence tomography scans (3D OCT-1000 Optical Coherence Tomographer, Topcon, Paramus, NJ, USA) were carried out at each visit. We collected Snellen visual acuity data at study entry and at final visit and length of follow-up. If there was a delay from presentation to the initiation of antiVEGF treatment, the Snellen visual acuity at the intravitreal injection (IVI) visit was recorded and used as the baseline visual acuity for comparison with the final visual acuity. We separated those eyes that developed VMT after CNVM treatment had commenced from those that had pre-existing VMT but also developed CNVM. The type of antiVEGF injections, ranibizumab or bevacizumab was also recorded. All data were held in an anonymous computerised database. The study had the approval of our Institutional Ethics Review Board.

RESULTS

The results from this series are summarised in Tables 123456. There were 7 eyes of 7 patients with co-existing CNVM and VMT, that required treatment with anti VEGF intravitreal injections (IVI) for the CNVM component. Table 1 lists the patient demographics and ocular features at presentation. All patients in this series were Caucasian, four were female (57%) and 3 were male (43%). The mean age at presentation was 74 years (range 64-95 years). All patients presented with blurring of central vision, rather than distortion. One patient had significant cataract (14%) and 1 other had nonproliferative diabetic retinopathy (14%). Only one of the patients (patient F) had been treated 14 months earlier for CNVM with verteporfin photodynamic therapy (PDT) and bevacizumab and had a reactivation of the CNVM at the time of the present study.

The aetiology of the CNVM is detailed in Table 2. A diagnosis of wet age-related macular degeneration (AMD) was made in 5 eyes (72%), angioid streaks in 1 eye (14%) and pathological myopia in 1 eye (14%). The fluorescein angiographic features of the CNVM were ascertained and described according to Macular Photocoagulation Study and updated criteria (Table 3). [START_REF]Subfoveal neovascular lesions in age-related macular degeneration. Guidelines for evaluation and treatment in the macular photocoagulation study. Macular Photocoagulation Study Group[END_REF][START_REF] Yannuzzi | Idiopathic polypoidal choroidal vasculopathy (IPCV)[END_REF][START_REF] Yannuzzi | Review of retinal angiomatous proliferation or type 3 neovascularization[END_REF] The CNVM was diagnosed as classic with no occult component in 1 eye (14%), predominantly classic in 1 eye (14%) and minimally classic in 1 eye (14%). Occult CNVM was diagnosed in 2 eyes (28%), 1eye (14%) showed features of retinal angiomatous proliferation, and 1(14%) had angiographic characteristics of idiopathic polypoidal choroidal vasculopathy (IPCV).

In our series of 7 eyes of 7 patients with co-existing VMT and active CNVM, 4 eyes (57%) were treated with intravitreal injections of ranibizumab and three (43%) with bevacizumab for the active CNVM component. The mean follow-up was 11 months (range 2-28 months). None of the eyes in this series required surgery for VMT. Visual acuity was stabilized or improved in 5 of the 7 eyes (71%) with IVI. Visual acuity results across the whole group were gain of 3 or more lines of Snellen visual acuity in 2 eyes (28%), gain of up to 3 lines in 3 eyes (42%), no change in visual acuity in 1 eye (14%) and loss of up to 3 lines in 1 eye (14%). There were no eyes losing more than 3 lines of Snellen visual acuity.

To examine the timing of onset or worsening of VMT in relation to the CNVM, this series was divided into those eyes with VMT and CNVM at presentation and those eyes that had CNVM and subsequently developed VMT after IVI initiation. There were 4 eyes of 4 patients (Table 4, patients A-D) in our series of 7 eyes (57%) that had pre-exisiting OCT features of VMT at the time of diagnosis of active CNVM. All of these eyes had the presence of subretinal fluid on OCT scan as well as the presence of hyaloid face traction on the macular surface, which increased with IVI (Figures 1 and2). All of these eyes were treated with IVI, with three eyes (75%) receiving ranibizumab and one eye (25%) receiving bevacizumab. Patient A, who had AMD and non-proliferative diabetic retinopathy, improved in visual acuity from 6/60 to 6/7.5 with IVI. On final OCT scan no subretinal fluid or fibrosis was noted but a worsening of VMT was noted. This eye received 3 injections of bevacizumab before the VMT increase and one after. Patient B, with AMD, improved in visual acuity from 6/24 to 6/18 with 2 IVI treatments. The final OCT confirmed the presence of intraretinal fluid, increased VMT, pigment epithelium detachment (PED) and elements of subfoveal fibrosis, so further IVI was not recommended. Patient C, with AMD that presented with a visual acuity of 6/24, worsened from a pre-treatment visual acuity of 6/60 to 6/90, with 1 IVI before progression of VMT and 1 IVI after progression of VMT. This eye had developed subfoveal fibrosis, so further intervention was not recommended. Final OCT showed intraretinal fluid and an increase in VMT. Patient D had the features of idiopathic polypoidal choroidal vasculopathy (IPCV) with no previous treatment. This eye received two injections of ranibizumab before the VMT increase and none after. The final OCT confirmed the presence of cystic intraretinal fluid and increased VMT. No subretinal fluid or fibrosis was noted and as visual acuity had improved from 6/18 to 6/12, with minimal residual activity of the CNVM, further IVI was not required.

Three eyes out of 7 (43%) did not have VMT on OCT scan when they started IVI for active CNVM (Table 5). After initiation of IVI, they developed antero-posterior traction from the vitreous to the macula (Figure 3). All of these eyes were treated with IVI, with one eye (33%) receiving ranibizumab and two eyes (67%) receiving bevacizumab. Patient E, with AMD and a retinal angiomatous proliferation lesion, did not improve vision from 6/60. At final visit there was a fibrosed retinal pigment epithelial detachment, with VMT on OCT scan. This eye had received 3 injections of ranibizumab before VMT onset and none after. Patient F developed CNVM from angioid streaks and had previously received 2 injections of bevacizumab and verteporfin photodynamic therapy for recurrent CNV 14 months before current reactivation. Follow-up was 15 months (4 months after the onset of VMT). The visual acuity improved from 6/18 to 6/9 and the final OCT confirmed the presence of intraretinal fluid, VMT and elements of subretinal fibrosis. Four injections of bevacizumab were given before the VMT onset and one after. Patient G with pathological myopia was followed up for 28 months (18 months after the onset of VMT). The visual acuity improved from 6/60 to 6/9 with IVI. The last OCT confirmed the presence of VMT and elements of subretinal fibrosis. A total of three injections of bevacizumab were administered before onset of VMT and four after.

The effect of the delay from diagnosis to treatment of CNVM on visual acuity change in this series was also ascertained (Table 6). In 2 of the 7 eyes (29%) there was no delay from diagnosis to IVI treatment, in 3 eyes (42%) there was a delay of 1 month and in 2 eyes (29%) there was a delay of 2 months. The final visual acuity was 6/9 in both eyes with no treatment delay, despite starting visual acuities of 6/18 and 6/60 after a follow-up period of 8 and 12 months after the last injection respectively. In the 3 eyes that had a delay of 1 month, visual acuity improved in 2 eyes (to 6/7.5 from 6/60 and to 6/12 from 6/18), but in 1 eye the visual acuity deteriorated from 6/60 to 6/90. In the 2 eyes that waited 2 months for initiation of IVI, the visual acuity stayed the same in 1 eye (visual acuity on presentation was 6/24 deteriorating to 6/60 during the 2 month delay) and in the other the improvement was 1 Snellen line from 6/24 to 6/18 (visual acuity on presentation was 6/18 and deteriorating to 6/24 during the 2 month delay).

DISCUSSION

Choroidal neovascularisation (CNVM) is an endpoint that is common to several underlying conditions, that disturbs macular function due to disruption of normal anatomical structures by intraretinal, subretinal or sub-retinal pigment epithelial fluid or haemorrhage. [START_REF] Bird | An international classification and grading system for age-related maculopathy and age-related macular degeneration. The International ARM Epidemiological Study Group[END_REF] Vitreomacular traction (VMT) is a condition in which the vitreous gel has an abnormally strong adhesion to the macular retina. [START_REF] Reese | Vitreomacular traction syndrome confirmed histologically[END_REF][START_REF] Hikichi | Course of vitreomacular traction syndrome[END_REF][START_REF] Margherio | Surgical management of vitreomacular traction syndromes[END_REF] Over time, the vitreous can pull forward distorting the retina and causing diffuse cystoid macular edema, associated with a thickened, taut, and glistening posterior hyaloid face. [START_REF] Hikichi | Course of vitreomacular traction syndrome[END_REF][START_REF] Massin | Optical coherence tomography for evaluating diabetic macular edema before and after vitrectomy[END_REF] The 2 conditions cause similar symptoms, with central visual blurring or distortion and occasionally the situation occurs where both co-exist. [START_REF] Maftouhi | Anomalous vitreoretinal adhesions in patients with exudative age-related macular degeneration: an OCT study[END_REF][START_REF] Mojana | The role of abnormal vitreomacular adhesion in agerelated macular degeneration: spectral optical coherence tomography and surgical results[END_REF][START_REF] Ondes | Role of the vitreous in age-related macular degeneration[END_REF] Though both CNVM and VMT have been well described in the literature, little attention has been paid to the situation where both conditions either co-exist or 7 VMT occurs after initiation of treatment for CNVM with intravitreal antiVEGF agents (IVI). In this study, we report our experience of the management of such eyes.

Visual acuity was either stabilized or improved in the majority of eyes (86%) in this study despite onset or worsening of VMT after initiation of IVI treatment for CNVM. One eye (14%) lost less than 3 Snellen visual acuity lines, but none lost greater than 3 lines in this unusual situation. In 4 eyes, with pre-existing VMT, IVI treatment improved visual acuity in 3 (75%) and in 3 eyes that had the onset of VMT after initiation of IVI, visual acuity improved in 2 (67%).

Although our series is small, retrospective and non-randomised, we would recommend treatment of the CNVM with IVI despite the presence of VMT. Our experience has been dissimilar to that of Mojana and associates, 8 who reported the use of surgery for VMT in 5 eyes that were refractory to CNVM treatment with IVI. A modest improvement in vision was found in that study with surgical removal of the posterior hyaloid face, and VMT may have formed a physical or chemical barrier to the resolution of macular anatomy. In our experience, either the visual acuity improved despite VMT, to a level above which the risks of surgical intervention outweighed the benefits or subfoveal fibrosis developed and surgery was deemed inappropriate. If there were still further potential to improve vision by VMT surgery, then this option would have been explored. Spontaneous resolution of VMT to form a posterior vitreous detachment occurred in 11% of eyes by 5 years in one report. [START_REF] Hikichi | Course of vitreomacular traction syndrome[END_REF] In our cases, none of the eyes had spontaneous resolution. Additionally, none of the eyes in this series had resolution of VMT from IVI, though this has been reported in a case of ranibizumab IVI used in diabetic macular oedema. [START_REF] Rouvas | Spontaneous resolution of vitreomacular traction following ranibizumab (Lucentis) injection[END_REF] It is interesting to note that both patients that started treatment on presentation improved their visual acuity to better than 6/9 at the end of the follow-up period. Delay in initiation of IVI therapy can occur if there is diagnostic confusion, as the appearance of VMT, particularly on OCT scans, can be dramatic. Eyes in this series that waited 1 or more months after the diagnosis of CNVM had modest improvement of vision at best, with only 1 exception that improved to 6/7.5. Although this study comprises a small number of eyes, we advocate use of IVI for CNVM as soon as the diagnosis is made even in eyes where the 2 conditions co-exist or VMT occurs and the CNVM remains active. If the CNVM is then controlled with IVI, and the eye still has potential to improve surgery for VMT may then be appropriate decided on a case-by-case basis. It is possible and probable that there will be cases where there will be benefit from surgery, but the AMD component should be treated with IVI adequately. Apportioning blame between the 2 conditions is difficult. Pointers include sequence of vision loss matching the onset of CNVM or VMT (which may be difficult to determine), change after the AMD component has stabilized, decrease of subretinal fluid with increase in distortion or predominant distortion (more likely to be related to VMT).

An implicating role for persistent VMT in eyes developing exudative macular degeneration has been suggested in several reports, but there is no consensus on a proposed mechanism. [START_REF] Maftouhi | Anomalous vitreoretinal adhesions in patients with exudative age-related macular degeneration: an OCT study[END_REF][START_REF] Krebs | Posterior vitreomacular adhesion: a potential risk factor for exudative age-related macular degeneration?[END_REF][START_REF] Ondes | Role of the vitreous in age-related macular degeneration[END_REF][START_REF] Weber-Krause | Incidence of posterior vitreous detachment in eyes with and without age-related macular degeneration. An ultrasonic study[END_REF][START_REF] Schulze | Vitreomacular traction and exudative age-related macular degeneration[END_REF] In these reports, different hypotheses have been formulated to explain the role of vitreomacular adhesion in AMD, focusing on both mechanical and biochemical factors underlying the observed phenomenon.

In the mechanical hypothesis, it is proposed that a pigment epithelial detachment may be induced by vitreomacular traction, which by exerting tangential forces may cause a rip of the retinal pigment epithelium or stimulate CNVM formation. [START_REF] Schulze | Vitreomacular traction and exudative age-related macular degeneration[END_REF][START_REF] Meyer | Retinal pigment epithelial tear with vitreomacular attachment: a novel pathogenic feature[END_REF] In the biochemical theory, VMT is proposed to induce hypoxic damage, causing an increase in growth factors such as VEGF to stimulate CNVM formation. [START_REF] Spaide | Choroidal neovascularization in age-related macular degeneration--what is the cause?[END_REF] However, the effect of VMT alone is unlikely to induce CNVM, as environmental, genetic and inflammatory factors are likely to play a large role in pathogenesis. [START_REF] Schulze | Vitreomacular traction and exudative age-related macular degeneration[END_REF] A posterior vitreous detachment assessed by ultrasound examination has been found to be protective against ARMD regardless of exudative or non-exudative ARMD in one series, [START_REF] Ondes | Role of the vitreous in age-related macular degeneration[END_REF] which may be important as a quarter of the population aged over 80-years-old may not have a complete posterior vitreous separation. [START_REF] Perichon | Ultrasonographic study of posterior vitreous detachment in emmetropic eyes[END_REF] Conversely, posterior vitreous detachment was not found to be associated with AMD in a large series of eyes examined clinically and with ultrasound. [START_REF] Hayreh | Posterior vitreous detachment: clinical correlations[END_REF] In a more recent study, VMT assessed by OCT was associated with the exudative form of ARMD in 36% of eyes versus 7% in dry ARMD and 10% in controls. [START_REF] Krebs | Posterior vitreomacular adhesion: a potential risk factor for exudative age-related macular degeneration?[END_REF] VMT is best demonstrated by OCT scan, and with OCT guided treatments of CNVM, it is likely that the discovery of VMT in eyes thought only to have CNVM on fluorescein angiography will become more common. [START_REF] Gallemore | Diagnosis of vitreoretinal adhesions in macular disease with optical coherence tomography[END_REF][START_REF] Lalwani | A variable-dosing regimen with intravitreal ranibizumab for neovascular age-related macular degeneration: year 2 of the PrONTO Study[END_REF] The vitreous macula interface has been found to be strongly adherent in eyes having verteporfin photodynamic therapy [START_REF] Schmidt | High incidence of vitreomacular traction in recurrent choroidal neovascularisation after repeated photodynamic therapy[END_REF] or submacular surgery [START_REF] Lambert | Surgical excision of subfoveal neovascular membranes in age-related macular degeneration[END_REF] for CNVM treatment.

In our study, none of the patients had to undergo vitreoretinal surgery and the majority responded well to the antiVEGF treatment despite the onset or the increase of vitreomacular traction.

Although further clinical studies with larger numbers of patients are needed, our study suggests that prompt treatment for the CNVM component should be initiated for the best chance of visual improvement

Figure 1 A

 1 Figure 1

Figure 2 A

 2 Figure 2 A. Colour fundus photograph of a 71-year-old female (Case D) presenting with an occult CNVM on fluorescein angiogram (B.) and the presence of idiopathic polypoidal choroidal vasculopathy on indocyanine green angiogram (C.). Baseline OCT scan (D.) showed vitreomacular traction, which increased after 2 injections of intravitreal antiVEGF therapy (E.). Visual acuity improved from 6/18 to 6/12.

Figure 3 A

 3 Figure 3 A. Colour fundus photograph of a 65-year-old male (Case E) presenting with an occult CNVM and retinal angiomatous proliferation on fluorescein angiogram (B). Baseline OCT scan (C.) did not show vitreomacular traction, which developed after 3 injections of intravitreal antiVEGF therapy (D.). Visual acuity remained 6/60.

Table 1 .

 1 Patient demographics.

	Features	Number (%)
		N=7
	Age (years)
	Mean ( Range)	73 ( 64-95)
	Race
	Caucasian	7 (100)
	Sex
	Male	3(43)
	Female	4(57)
	Ocular co morbidity
	Cataract	1(14)
	Diabetic retinopathy(NPDR)	1(14)
	Ocular symptoms
	Decreased visual acuity	7 (100)
	Previous Treatments
	Bevacizumab+PDT	1(14)
	None	6(86)
	PDT = verteporfin photodynamic therapy
			Table 2. Choroidal neovascular
	Aetiology	Number (%)	membrane aetiology
		N=7
	AMD	5 (72)
	Angioid streaks	1(14)
	Myopia	1(14)
			Table 3. Choroidal neovascular
	Subtype	Number (%)	membrane subtype on fluorescein
		N=7	angiography
	Classic	1(14)
	Predominantly classic	1(14)
	Minimally classic	1(14)
	Occult CNV	2(28)
	IPCV	1(14)
	RAP	1(14)

Table 5 .

 5 Patients with vitreomacular traction onset after VEGF treatment N=3 (E-G)

	Patient Age	sex Diagnosis	Baseline best	Number of antiVEGF	Number of	Final best	Follow-up
		years		(CNVM	corrected	injections before	antiVEGF	corrected	(months)
				subtype)	Snellen visual	VMT onset	injections after	Snellen visual
					acuity		VMT onset	acuity
	E	65	M	RAP(Occult)	6/60	3	0	6/60	10
	F	64	M	Angioid	6/18	4	1	6/9	15
				streaks
				(Occult)
	G	65	F	Myopic CNV	6/60	3	4	6/6	28
				(Minimally
				classic)
			M=male
			F=female

Table 6 .

 6 Time interval between presentation and treatment and effect on visual acuity N=7(A-G)

	Patient	Best corrected Snellen	Best corrected Snellen	Final best corrected	Interval between	Interval between fin
		visual acuity on	visual acuity on first	Snellen visual acuity	presentation and first	injection and final
		presentation	treatment		treatment(months)	follow-up (months)
	A	6/24	6/60	6/7.5	1	3
	B	6/18	6/24	6/18	2	4
	C	6/24	6/60	6/90	1	1
	D	6/18	6/18	6/12	1	4
	E	6/24	6/60	6/60	2	5
	F	6/18	6/18	6/9	0	8
	G	6/60	6/60	6/6	0	12