IOL system a novel surgical treatment for dry AMD
A new intraocular mini-telescope is easy to implant through a small incision and has optimized optics so that it reliably provides good quality vision.
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By Cheryl Guttman Krader; Reviewed by Pablo Artal, PhD; Fritz Hengerer, MD, PhD; and Bobby Qureshi, MD
London-A new intraocular mini-telescope (iolAMD, London Eye Hospital Pharma) offers significant surgical and optical advantages compared with previous technology, and its features make it an exciting advance for cataract surgery patients with vision loss related to macular disease.
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"The new IOL allows for happy patients, because it is associated with faster visual rehabilitation compared with previous intraocular telescopes and better quality vision," said Bobby Qureshi, MD, consultant ophthalmic surgeon, and chief medical officer and founder, London Eye Hospital Pharma, London.
"In addition, it makes for happier surgeons," Dr. Qureshi added. "The implantation procedure is simple and fast, has a short learning curve because it involves existing skills, and it has safety advantages because the lenses are injected through a small incision and situated in the posterior chamber, away from sensitive corneal structures."
Age-related macular degeneration (AMD) is the most common cause of blindness in people over age 55 in the developed world, with more than 20 million sufferers in the United States and between 200 million to 300 million worldwide. It is estimated that by 2020, there will be nearly 30 million cases of AMD in the United States alone, noted Rob Hill, chief executive officer, London Eye Hospital Pharma, London.
"[The innovation] is the first patient- and surgeon-friendly procedure to address the symptoms of dry AMD," Hill said.
The platform is CE marked and commercially available in some European countries, but not FDA approved. It is the product of a collaboration between Dr. Qureshi and Pablo Artal, PhD. The goals were to create a system that it would be easy to implant through a small incision and reliably provide good quality vision.
Using ray-tracing techniques, Dr. Qureshi conceived the idea and refined his concept of an intraocular mini-telescope combining two foldable lenses, one in the ciliary sulcus and the other in the capsular bag. Then he enlisted the help of Dr. Artal for his optics expertise. Applying wavefront analysis, Dr. Artal optimized the lens optics to improve retinal image quality and allow increased tolerance to variations in relative lens positioning.
The new commercially available platform consists of two hydrophobic acrylic plate haptic IOLs-a high-plus powered lens (+60 D) with a 5-mm optic and asymmetrical haptics placed in the sulcus and a high-minus powered lens (–50 to –60 D) with a 4-mm optic placed in the capsular bag. The asymmetrical haptics of the sulcus IOL result in an offset of 0.85 mm between the two lenses. Together, they create a Galilean telescopic effect with about 1.3× and 3º of foveal displacement.
The amount of magnification provided increases visual acuity without compromising visual field, and therefore enables binocular implantation. The lenses are made of a high refractive index, foldable, glistenings-free material and can be easily implanted through a 3-mm incision.
Though modest about his contributions for optimizing the optics, Dr. Artal is genuinely impressed by comments of patients with the intraocular mini-telescope implanted.
"These individuals are very happy and extremely thankful for their improved vision," said Dr. Artal, professor of physics, University of Murcia, Spain. He added that since the design of the new lens makes intraocular telescope implantation feasible for more surgeons, its benefits will be available to a greater number of patients.
Pathway to a new platform
Soon after he began to implant intraocular mini-telescopes in 2007 using the IOLVIP, Dr. Qureshi became interested in developing an alternative that would be based on injectable optics and provide good image quality despite the aberrations and distortions associated with high-powered lenses, magnification, and the prismatic effect.
Decentering the lenses by 0.85 mm provided the desired 3º of foveal displacement of the image, but also induced astigmatism and coma. Dr. Artal implemented shape factors and asphericity to correct for those aberrations in order to improve image quality, and further refined the asphericity to improve tolerance to variations in lens positioning.
"Image quality is quickly reduced with standard lenses if they are not properly positioned," Dr. Artal said. "Adding a significant amount of asphericity increases the tolerance in lens position by at least six-fold.
"Yet, in physics you do not get something for nothing. The tradeoff for the benefit we achieved is a slight decrease in image quality at best focus," he said. "However, because the patients implanted with the lens have lower visual requirements to begin with, the images that are produced are of sufficient quality for the purpose of enhanced extrafoveal viewing."
The amount of asphericity present in the lenses makes them suitable for a range of eye sizes. The current device is suitable for patients with a spherical error between –4 D and +4 D and up to 3 D of astigmatism. A larger range encompassing longer and shorter eyes will be available in 2015 as will a version for pseudophakic eyes.
Simple surgery
Dr. Qureshi said the new device fulfills his goal to create a system that can be implanted by any competent cataract surgeon. The procedure itself just takes a few extra minutes compared with standard IOL implantation.
Preoperatively, a simulation test is performed to assess whether the patient will benefit from the implantation and to allow the surgeon to determine proper orientation of the sulcus lens.
The procedure involves creation of a 5-mm capsulorhexis. After performing routine phaco through a 2-mm incision, Dr. Qureshi extends the entry site to 3 mm and introduces the posterior IOL into the capsular bag with an injector.
"The material has very good memory, centers very nicely with minimal manipulation, and orientation is as per any capsular bag lens," he said.
The sulcus lens is injected behind the iris and oriented based on the findings of the preoperative simulation to move the image to the chosen area of healthier retina. Due to the haptics design, there is no need for iridotomy or iridectomy. However, surgeons do need to meticulously remove all viscoelastic from behind the IOL that is in the capsular bag and from between the two lenses, Dr. Qureshi said.
Dr. Qureshi has implanted the intraocular mini-telelescope in more than 100 eyes with a variety of macular pathologies, including early to advanced age-related macular degeneration (AMD), diabetic maculopathy, macular holes, Stargardt's disease, and Best's disease.
In addition, he has performed lens exchange, implanting the mini-telescope after explanting a monofocal IOL. However, he recommended surgeons begin by choosing phakic patients with stable, dry AMD who are undergoing cataract surgery and who have visual acuity ranging from 6/20 to 6/200.
Fritz Hengerer, MD, PhD, reported outcomes achieved after 4 months of follow-up in 18 eyes implanted by Dr. Qureshi along with his own initial clinical experience with the intraocular mini-telescope. For the eyes in Dr. Qureshi's series, mean Snellen preoperative near uncorrected visual acuity (UCVA) (decimal) was worse than 0.14, preoperative distance best-corrected visual acuity (BCVA) was 0.12, and simulated distance BCVA was 0.19. Mean postoperative distance BCVA was 0.2, exceeding the simulation-predicted value, and mean near BCVA improved by 50% to 0.21.
The refractive outcomes were similar to those achieved with monofocal implants. There was a myopic shift in all cases from pre- to postoperative (mean 1.5 D) and a mean of about 0.5 D of induced astigmatism. However, the refractive changes can be neglected, said Dr. Hengerer, assistant professor of ophthalmology, Goethe-University Frankfurt am Main, Frankfurt, Germany.
There were no intraoperative or postoperative complications. Mean IOP was 18 mm Hg preoperatively and 16 mm Hg postoperatively, and mean endothelial cell count showed a decrease of about 18%.
Images from anterior segment OCT demonstrated stable lens positioning, and microperimetry results confirmed the benefit of the telescopic and prismatic effect for improving threshold sensitivity and fixation stability.
Dr. Hengerer said he performed his first implantation of the intraocular mini-telescope in July 2014, in a patient with stage 3 AMD who had a monofocal IOL in the fellow eye. His next two cases were in the fellow eyes of a second patient with stage 3 AMD. All of the procedures were done through a 3.2-mm superior incision with a 5.0-mm capsulorhexis.
In the first implanted eye, baseline distance BCVA was 0.03. The patient was unable to read with that eye, but the simulation predicted near BCVA would improve to 0.1 after implantation of the intraocular mini-telescope. At 30 days postoperatively, near and distance UCVA were both 0.25, distance BCVA was 0.4 and near BCVA was 0.5.
"With these outcomes, the patient had visual acuity that allowed him to keep his driver's license," Dr. Hengerer said.
The results from the second patient who received the intraocular mini-telescope in both eyes suggested outcomes are enhanced with binocular summation. Preoperatively, distance BCVA was 0.05 in the left eye and 0.16 in the right eye. The patient was unable to read with his right eye and had 0.16 BCVA at near in the left eye. In binocular testing at 30 days after the second eye surgery, distance UCVA was 0.5, near UCVA was 0.63, and BCVA for both near and distance was 0.8.
"The patient is very happy and particularly pleased because he is able to read stories to his grandchildren, which he could not do before," Dr. Hengerer said.
Dr. Hengerer also emphasized the importance of completely removing viscoelastic between the two lenses to optimize their relative positioning, and he noted that there is the potential to adjust the orientation of the sulcus lens in a future procedure in order to improve vision for patients when their macular pathology advances.
"The sulcus IOL is not fixed like a toric lens, but can be rotated later according to the patient's needs, potentially extending vision as the disease progresses," Dr. Hengerer said.
Pablo Artal, PhD
E: pablo@um.es
Dr. Artal is a consultant to London Eye Hospital Pharma.
Fritz Hengerer, MD, PhD
E: fritz.hengerer@kgu.de
Dr. Hengerer has no relevant financial interest to disclose.
Bobby Qureshi, MD
E: bqureshi@LEHpharma.com
Dr. Qureshi is the founder of London Eye Hospital Pharma who developed iolAMD.
This article was adapted from an industry-sponsored symposium during the 2014 meeting of the European Society of Cataract and Refractive Surgeons.
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