A randomized paired eye comparison of two techniques for treating moderately high myopia: LASIK and artisan phakic lens. Randomized prospective comparison of visian toric implantable collamer lens and conventional photorefractive keratectomy for moderate to high myopic astigmatism. Randomized bilateral comparison of excimer laser in situ keratomileusis and photorefractive keratectomy for 2.50 to 8.00 diopters of myopia. Comparison of photorefractive keratectomy with excimer laser in situ keratomileusis in correcting low myopia (from -2.00 to -5.50 diopters). A randomized study. Photorefractive keratectomy with mitomycin C versus LASIK in custom surgeries for myopia: a bilateral prospective randomized clinical trial. A prospective, randomized, double-masked comparison of a zonal-progressive multifocal intraocular lens and a monofocal intraocular lens. Atropine for the treatment of childhood myopia. The effectiveness of progressive addition lenses on the progression of myopia in Chinese children. Prospective intrapatient comparison of 6.0-millimeter optic single-piece and 3-piece hydrophobic acrylic foldable intraocular lenses. A randomized trial of rigid gas permeable contact lenses to reduce progression of children's myopia. Photorefractive keratectomy versus laser in situ keratomileusis for moderate to high myopia. A randomized prospective study.
To compare refractive performance and safety of laser in situ keratomileusis (LASIK) and Artisan phakic intraocular lens (PIOL) for moderately high myopia.
                A prospective, randomized trial with paired eye control.
                Twenty-five patients with myopia ranging from -8.00 to -12.00 diopters (D).
                For each patient, one eye received LASIK and the other one was implanted with an Artisan phakic intraocular lens. The treated eye and the surgical technique were randomized.
                Primary outcome measure was spherical equivalent refraction. Main secondary outcome measures were the change of two or more lines and safety index (ratio postoperative to preoperative best-corrected visual acuity).
                One year after surgery, the mean spherical equivalent refraction was -0.74 +/- 0.67 D for LASIK-treated eyes and -0.95 +/- 0.45 D for Artisan-treated eyes, and the majority of LASIK-treated eyes (64%) and Artisan-treated eyes (60%) were within +/-1.00 D of the intended result. At 1 month, the mean spherical equivalent refraction was -0.28 +/- 0.71 D for LASIK and -1.07 +/- 0.59 D for Artisan (P < 0.01). The changes of two or more lines were in favor of Artisan (P < 0.05). The safety index was significantly better for Artisan (1.12 +/- 0.21) than for LASIK (0.99 +/- 0.17) at 1 year (P < 0.02).
                In cases of moderately high myopia, LASIK and Artisan phakic intraocular lenses seemed to produce a similar predictability. The best-corrected visual acuity and subjective evaluation of quality of vision were better for Artisan. To compare the Visian Toric Implantable Collamer Lens (TICL), a toric phakic intraocular lens (IOL), and photorefractive keratectomy (PRK) in the correction of moderate to high myopic astigmatism.
                This prospective, randomized study consisted of 43 eyes implanted with the TICL (20 bilateral cases) and 45 eyes receiving PRK with mitomycin C (22 bilateral cases) with moderate to high myopia (-6.00 to -20.00 diopters [D] sphere) measured at the spectacle plane and 1.00 to 4.00 D of astigmatism. All patient treatment and follow-up occurred at the Naval Medical Center San Diego. Study follow-up was 1 day, 1 week, 1, 3, 6, and 12 months postoperative.
                Mean best spectacle-corrected visual acuity (BSCVA), change in BSCVA, proportion of cases with improvement of 1 or more lines of BSCVA, proportion of cases with BSCVA and uncorrected visual acuity (UCVA) 20/12.5 or better, proportion of cases with BSCVA and UCVA 20/16 or better (6 months, 88% vs 54%, P=.002), and predictability +/-1.00 D (6 months, 100% vs 67%, P<.001) were all significantly better in the TICL group than the PRK group at all time periods studied postoperatively. Similarly, contrast sensitivity, tested at both the 5% photopic level and the 25% mesopic level, was significantly better at all postoperative time points in the TICL group. Mean spherical equivalent refraction was closer to emmetropia (0.28+/-0.41 vs 0.76+/-0.86, P=.005), and predictability +/-0.50 D and stability of manifest refraction (+/-0.50 D and +/-1.00 D) were significantly better in the TICL group at all postoperative visits through 6 months. Mean astigmatism correction at 6 months was not significantly different between the two groups (0.52+/-0.33 vs 0.46+/-0.35, P=.450).
                The TICL performed better than PRK in all measures of safety (BSCVA), efficacy (UCVA), predictability, and stability in this comparison, supporting the TICL as a viable alternative to existing refractive surgical treatments. To compare effectiveness, safety, and stability of excimer laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) for low-to-moderate myopia.
                Prospective, randomized, bilateral study.
                Thirty-three patients with a manifest refraction of -2.50 to -8.00 diopters (D) participated.
                For each patient, one eye received LASIK and the other received PRK. The first eye treated, and surgical method in the first eye, were randomized. Both eyes were treated by the same surgeon during the same operative session with a Summit Omnimed I laser (6-mm-diameter ablation) and a Chiron Automated Corneal Shaper. Follow-up was 90% at 1 and 2 years.
                At baseline, mean (+/-standard deviation) spherical equivalent manifest refraction was -4.80 +/- 1.60 D in LASIK-treated eyes and -4.70 +/- 1.50 D in PRK-treated eyes. At 1 day after surgery, 81% of patients (21 eyes) reported no pain in the LASIK-treated eye, whereas no patient (0%) reported being pain-free in the PRK-treated eye. At 3 to 4 days after surgery, 18 (80%) LASIK-treated eyes either improved or remained within 1 line of baseline spectacle-corrected visual acuity; only 10 (45%) PRK-treated eyes achieved this result. At 2 years after surgery, 18 (61%) LASIK- and 10 (36%) PRK-treated eyes achieved an uncorrected visual acuity of 20/20 or better, with no statistically significant difference in refractive outcome between the two techniques. Quantitative videokeratography showed more regularity after LASIK. Complications were similar in the two groups. Patients preferred LASIK by a margin of 2 to 1 at 1 year but showed no preference at 2 years.
                Using a 6-mm-diameter single-pass, large area ablation and an automated microkeratome to treat myopia of -2.50 to -8.00 D with 1.00 D or less astigmatism in 1994, the authors used LASIK to produce a higher percentage of eyes with an uncorrected visual acuity of 20/20 or better, more regular postoperative corneal topography, less postoperative pain, and more rapid recovery of baseline spectacle-corrected visual acuity than PRK. Both LASIK and PRK achieved successful correction of low-to-moderate myopia at 1 and 2 years after surgery. To compare laser in situ keratomileusis (LASIK) with photorefractive keratectomy (PRK) in the correction of myopia from -2.00 to -5.50 diopters.
                Prospective, randomized, paired clinical trial.
                Fifty-two eyes of 26 myopic patients were enrolled in the study.
                Each patient received PRK on one eye (PRK eye) and LASIK on the other (LASIK eye); the procedure assigned to each eye, and the sequence of surgeries for each patient was randomized.
                Slit-lamp microscopy, manifest refraction, uncorrected and spectacle-corrected visual acuity, and videokeratography were done before operation, and 2 weeks, 6 weeks, 3 months, 6 months, and 12 months after operation. Patient satisfaction and preference were assessed by a subjective questionnaire.
                All LASIK eyes had fast, painless recovery. At 1 year, 24 patients (92.3%) were examined, the mean spherical equivalent refraction was -0.08 +/- 0.38 diopter in the PRK eyes and -0.14 +/- 0.31 diopter in the LASIK eyes, and the uncorrected visual acuity was 20/20 or better in 15 PRK eyes (62.5%) and 19 LASIK eyes (79.2%); no eye lost 2 or more Snellen lines of spectacle-corrected visual acuity. Both procedures were stable throughout the first year. One PRK eye developed dense subepithelial corneal haze. The strongest correlate to spectacle-corrected visual acuity after the two procedures was the coefficient of variation of corneal power over the pupil. Nineteen patients (79.2%) preferred the LASIK procedure because of the fast, painless recovery.
                In the current study, PRK and LASIK were found to be similarly effective, predictable, stable, and reasonably safe for the correction of myopia between -2.00 and -5.50 diopters. Laser in situ keratomileusis has the advantage of fast, painless recovery. Patients prefer LASIK. To compare photorefractive keratectomy (PRK) with prophylactic use of mitomycin C (MMC) and LASIK in custom surgeries for myopic astigmatism.
                Eighty-eight eyes of 44 patients with a minimum estimated ablation depth of 50 microm were randomized to receive PRK with MMC 0.002% for 1 minute in one eye and LASIK in the fellow eye. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), cycloplegic refraction, slit-lamp microscopy, contrast sensitivity, specular microscopy, aberrometry, and a subjective questionnaire were evaluated. Forty-two patients completed 6-month follow-up.
                Mean spherical equivalent refraction error before surgery and mean ablation depth were -3.99+/-1.20 diopters (D) and 73.09+/-14.55 microm in LASIK eyes, and -3.85+/-1.12 D and 70.7+/-14.07 microm in PRK with MMC eyes, respectively. Uncorrected visual acuity was significantly better in PRK with MMC eyes 3 months (P=.04) and 6 months (P=.01) after surgery. Best spectacle-corrected visual acuity and spherical equivalent refraction did not differ significantly in the groups during follow-up (P>.05). Significant haze was not observed in any PRK with MMC eye. Mean higher order aberration was lower in PRK with MMC eyes postoperatively compared with LASIK eyes (P=.01). Better contrast sensitivity was observed in PRK with MMC eyes than LASIK eyes (P<.05). The endothelial cell count did not differ significantly between groups (P=.65). In terms of visual satisfaction, PRK with MMC eyes were better rated.
                Photorefractive keratectomy with MMC appears to be more effective than LASIK in custom surgery for moderate myopia. During 6-month follow-up, no toxic effects of MMC were evident. Long-term follow-up is necessary to attest its safety. Multifocal intraocular lenses (IOLs) have been designed to provide improved near visual acuity without spectacles compared with monofocal IOLs. Early studies have reported variables amounts of decreased visual acuity and contrast sensitivity with multifocal IOLs, and some patients have experienced halos and glare.
                The authors performed a prospective, double-masked, multicenter evaluation of 62 patients randomized between a new zonal-progressive optic multifocal IOL and a monofocal IOL.
                Mean postoperative spherical equivalent, astigmatism, and uncorrected and best-corrected distance visual acuity were similar between the two groups. Patients with a multifocal IOL achieved significantly better uncorrected near visual acuity than patients with monofocal IOLs (J3+ versus J7; P less than 0.0001). With distance correction only, mean near visual acuity was J2 versus J5- (P = 0.0001). Best-corrected near visual acuity was J1 for both groups, with 1.36 diopters (D) for the multifocal group versus 2.37 D for the monofocal group (P less than 0.0001). Regan contrast sensitivity was lower for the multifocal patients at all contrast levels, and achieved statistical significance at very low contrast (11% contrast; P = 0.0024). Fifty-two percent of patients with a multifocal IOL reported that they did not need spectacles at all or used them only for their fellow eye, compared with 25% of the patients with monofocal IOLs.
                Both monofocal and multifocal implant patients were very satisfied with the results of their cataract extraction and IOL implant surgery. A small loss of contrast sensitivity with the multifocal IOL was demonstrated, consistent with theoretical predictions. The functional significance of the loss of contrast sensitivity appears to be small and counterbalanced by the advantage of improved uncorrected near visual acuity. To evaluate the efficacy and safety of topical atropine, a nonselective muscarinic antagonist, in slowing the progression of myopia and ocular axial elongation in Asian children.
                Parallel-group, placebo-controlled, randomized, double-masked study.
                Four hundred children aged 6 to 12 years with refractive error of spherical equivalent -1.00 to -6.00 diopters (D) and astigmatism of -1.50 D or less.
                Participants were assigned with equal probability to receive either 1% atropine or vehicle eye drops once nightly for 2 years. Only 1 eye of each subject was chosen through randomization for treatment.
                The main efficacy outcome measures were change in spherical equivalent refraction as measured by cycloplegic autorefraction and change in ocular axial length as measured by ultrasonography. The primary safety outcome measure was the occurrence of adverse events.
                Three hundred forty-six (86.5%) children completed the 2-year study. After 2 years, the mean progression of myopia and of axial elongation in the placebo-treated control eyes was -1.20+/-0.69 D and 0.38+/-0.38 mm, respectively. In the atropine-treated eyes, myopia progression was only -0.28+/-0.92 D, whereas the axial length remained essentially unchanged compared with baseline (-0.02+/-0.35 mm). The differences in myopia progression and axial elongation between the 2 groups were -0.92 D (95% confidence interval, -1.10 to -0.77 D; P<0.001) and 0.40 mm (95% confidence interval, 0.35-0.45 mm; P<0.001), respectively. No serious adverse events related to atropine were reported.
                Topical atropine was well tolerated and effective in slowing the progression of low and moderate myopia and ocular axial elongation in Asian children. To evaluate the effectiveness of progressive addition lenses (PALs), with a near addition of +1.50 D, on the progression of myopia in Chinese children.
                We enrolled 178 Chinese juvenile-onset acquired myopes (aged 7-13 years, -0.50 to -3.00 D spherical refractive error), who did not have moderately or highly myopic parents, for a 2-year prospective study. They were randomly assigned to the PAL group or single vision (SV) group. Primary measurements, which included myopia progression and ocular biometry, were performed every 6 months. Treatment effect was adjusted for important covariates, by using a multiple linear regression model.
                One hundred and forty-nine subjects (75 in SV and 74 in PAL) completed the 2-year study. The myopia progression (mean +/- S.D.) in the SV and PAL groups was -1.50 +/- 0.67 and -1.24 +/- 0.56 D, respectively. This difference of 0.26 D over 2 years was statistically significant (p = 0.01). The lens type (p = 0.02) and baseline spherical equivalent refraction (p = 0.05) were significant contributing factors to myopia progression. Mean increase in the depth of vitreous chamber was 0.70 +/- 0.40 and 0.59 +/- 0.24 mm, respectively. This difference of 0.11 mm was statistically significant (p = 0.04). Age (p < 0.01) was the only contributing factor to the elongation of vitreous chamber. Different near phoria (p < 0.01) and gender (p = 0.02) caused different treatment effects when wearing SV lenses. However, there were no factors found to influence the treatment effect of wearing PALs.
                Compared with SV lenses, myopia progression was found to be retarded by PALs to some extent in Chinese children without moderately or highly myopic parents, especially for subjects with near esophoria or females. To compare postoperative performance and stability of 6.0-mm optic single- and 3-piece acrylic foldable intraocular lenses (IOLs).
                Prospective, randomized, self-controlled trial.
                Eighty eyes of 40 patients with bilateral senile cataracts.
                Phacoemulsification and IOL implantation were performed. One eye of a patient was randomly assigned to the SA60AT single-piece IOL, and the contralateral eye was allocated to the MA60AC 3-piece IOL.
                Best-corrected visual acuity (BCVA), spherical equivalent, aqueous flare intensity, anterior chamber depth, amount of IOL decentration and tilt, area of anterior capsule opening, and degree of posterior capsule opacification (PCO) were measured 2 days, 1 week, and 1, 3, 6, and 12 months after surgery. Specular microscopy was performed at 12 months postoperatively.
                In the SA60AT group, the anterior chamber depth did not show significant changes after surgery (P>0.05; paired t test), and the refraction remained highly stable throughout the 1-year study period. The MA60AC group showed significant shallowing of the anterior chamber (P<0.05) and a myopic shift (P<0.05) up to 1 month after surgery. There were no significant differences between the 2 groups (P>0.05) in BCVA, aqueous flare intensity, the amount of IOL decentration, IOL tilt, area of anterior capsule opening, and degree of PCO throughout the 12-month follow-up period.
                Both the SA60AT single-piece and MA60AC 3-piece lenses showed a minimum amount of decentration, tilt, anterior capsule contraction, and PCO. Although the MA60AC showed significant forward shift and myopic refractive changes after surgery, the SA60AT displayed little axial movement associated with highly stable refraction after surgery. This feature of the SA60AT should facilitate earlier spectacle prescription and quicker visual/social rehabilitation of patients after cataract surgery. To test whether rigid gas permeable (RGP) contact lens wear can reduced the rate of myopia progression in school age children.
                Randomized clinical trial.
                
                Single clinical center.
                Both eyes of 428 Singaporean children.
                6 through 12 years of age with myopia between -1 and -4 diopters, astigmatism <or= 2 diopters, no prior contact lens wear, no other ocular pathologies.Intervention: Spectacle or RGP lens correction for myopia. After a 3-month adaptation period, 383 children were followed, and 298 (78%) remained after 24 months. Outcome measures: Cycloplegic subjective refraction, keratometry, and axial length measured at 12 and 24 months.
                Children who adapted to contact lenses wore them for a median of 7 hours per day, but no more than 40% wore them at least 8 hours per day, 7 days per week. Spectacles were worn for a median of 15 hours per day at the time of the 24-month follow-up. There was an increase in the spherical equivalent of -1.33 and -1.28 diopters (P =.64), and axial length increased by 0.84 and 0.79 mm (P =.38) over 2 years among children randomized to contact lenses and spectacles, respectively. Adjustment for baseline differences between the groups and for hours per day of contact lens wear did not alter these findings.
                Rigid gas permeable lenses did not slow the rate of myopia progression, even among children who used them regularly and consistently. It is unlikely that this intervention holds promise as a method by which to slow the rate of progression of myopia in children. This report presents the results of a randomized clinical trial of photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK).
                A randomized, prospective multicenter clinical trial.
                A total of 220 eyes of 220 patients entered the study cohort: 105 randomized to PRK and 115 to LASIK. The mean preoperative manifest refraction spherical equivalent was -9.23 diopters (D) in the PRK group and -9.30 D in the LASIK group.
                All patients received a one-pass, multizone excimer laser ablation as part of either a PRK or LASIK procedure using the Summit Apex excimer laser. Attempted corrections ranged from 6.00 to 15.00 D.
                Data on uncorrected and spectacle-corrected visual acuity, predictability,and stability of refraction, corneal haze, and flap complications were analyzed. Patients were observed for up to 6 months.
                One day after surgery, 0 (0.0%) and 3 (4.5%) eyes in the PRK group saw 20/20 and 20/40 or better uncorrected, respectively, while 7 (10%) and 48 (68.6%) eyes in the LASIK group saw 20/20 and 20/40 or better, respectively. At 6 months after PRK, 13 (19.1%) and 45 (66.2%) eyes saw 20/20 and 20/40 or better, respectively, while after LASIK, 16 (26.2%) and 34 (55.7%) eyes saw 20/20 and 20/40 or better, respectively (odds ratio = 0.56 for likelihood of uncorrected visual acuity < 20/40 for PRK vs. LASIK, 95% confidence interval [CI] = 0.31-1.19). After PRK, 39 eyes (57.4%) were within 1.0 D of attempted correction compared with 24 eyes (40.7%) in the LASIK group (odds ratio = 0.50 for likelihood fo undercorrection 1.0 D for PRK vs. LASIK, 95% CI = 0.24-1.04); however, the standard deviation of the predictability was similar between groups: 1.01 D for PRK and 1.22 D for LASIK. From months 1 to 6, there was an average regression of 0.89 D in the PRK group and 0.55 D in the LASIK group. After PRK, eight eyes (11.8%) had a decrease in spectacle-corrected visual acuity of two Snellen lines or more; after LASIK, two eyes (3.2%) had a decrease of two lines or more (odds ratio = 3.89 for risk of loss of spectacle-corrected visual acuity for PRK vs. LASIK, 95% CI = 0.71-21.30). Only two eyes had postoperative spectacle-corrected visual acuity less than 20/32, however.
                Although improvement in uncorrected visual acuity is more rapid in LASIK than in PRK, efficacy outcomes in the longer term generally are similar between the two procedures. There is a greater tendency toward undercorrection in LASIK eyes using the specific laser and nomogram in this study, but the scatter in achieved versus attempted correction is similar, suggesting little difference in the accuracy of the two procedures. A suggestion of decreased propensity for loss of spectacle-corrected visual acuity in LASIK eyes requires further investigation.
The results of this review suggest that phakic IOLs are safer than excimer laser surgical correction for moderate to high myopia in the range of -6.0 to -20.0 D and phakic IOLs are preferred by patients. While phakic IOLs might be accepted clinical practice for higher levels of myopia (greater than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism), it may be worth considering phakic IOL treatment over excimer laser correction for more moderate levels of myopia (less than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism). Further RCTs adequately powered for subgroup analysis are necessary to further elucidate the ideal range of myopia for phakic IOLs.