EyeWorld Asia-Pacific September 2011 Issue

September 2011 11 EW FEATURE continued on page 13 Robert ANG, MD Cornea and Refractive Surgeon, Asian Eye Institute 8th Floor Phinma Plaza, Rockwell Center, Makati City, Philippines Tel. no. +632-8982020 Fax no. +632-8982002 RTAng@asianeyeinstitute.com A re accommodating IOLs the emerging trend in presbyopic correction during cataract surgery? It would seem so with the number of products in the pipeline waiting for US FDA approval. Being the first in the market, the Crystalens gave us a snapshot of what an accommodating lens can do and what problems may arise with this technology. After 2 years of using the Crystalens HD and AO in about 350 eyes, the lens has become a vital addition to my cataract and refractive practice. It has not replaced my usage of multifocal IOLs but it has given my patients a wider range of choices. We can discuss their lifestyle and use the lens that can best fit their needs. Just like any lens, multifocal or monofocal, Crystalens performance is dependent on achieving and maintaining a good refractive outcome. If one achieves the recommended refraction of plano to –0.50D, the most likely uncorrected visual outcome is 20/25 (6/7.5) for distance, 20/20 (6/6) for intermediate and J3 for near vision. A mini-monovision target between eyes can further enhance the range of vision. The most significant advantage of the Crystalens is that it performs better than a monofocal IOL by giving good intermediate and fair near vision but avoids the decreased contrast, glare and haloes that are caused permanently by the multifocal lenses. I have heard the various criticisms against the Crystalens and I can say that just like all lenses, premium or otherwise, it is not perfect. One of the most important hurdles accommodating IOLs will face is how it reacts to capsular fibrosis and capsular forces that may alter its proposed function. I have observed that capsular opacity comes earlier in the Crystalens compared with the multifocal IOLs. More importantly, the capsule is stretched along the long axis of the lens and this is where capsular contraction often occurs. Thickening of the capsule under the plate haptic with the resultant contraction and striae formation causes the haptic plate to vault forward. An asymmetric capsule contraction is what we call a Z syndrome. Resolving it is difficult but not impossible. Preventing its occurrence may be the better way to go. I believe a timely and proper YAG capsulotomy will help prevent asymmetric contraction and maintain a good refractive and visual outcome with the Crystalens. We look forward to the approval of the Tetraflex, Synchrony and other innovative lenses as we journey towards improving accommodative technology further. Editors’ note: Dr. Ang is a consultant for Bausch & Lomb. Views from Asia-Pacific Ronald YEOH, FRCS, FRCOphth, DO, FAMS Senior Consultant, Singapore National Eye Centre 11 Third Hospital Avenue, Singapore 168751 Consultant Eye Surgeon & Medical Director, Eye & Retina Surgeons #13-03 Camden Medical Centre, 1 Orchard Boulevard, Singapore 248649 Tel. no. +6567382000 Fax no. +6567382111 snecyls@snec.com.s g T oday, the desire to overcome presbyopia after cataract surgery has never been stronger. Phaco cataract surgery is quick, safe and outstandingly efficacious in also resolving refractive errors like myopia, hyperopia and astigmatism. However, the ideal lens to treat presbyopia is still the subject of much research and debate. In this article, several accommodative lens implants, present and future, are discussed. Whenever a new and potentially useful implant is put forth, understandably there is great enthusiasm generated by vested parties. Often however, the benefits are highlighted and any limitations or drawbacks are glossed over. For example, the Crystalens HD was launched several years ago amidst reports of great results. It did not take many implantations to realize that the promised accommodative results were not forthcoming and in fact there were issues with quality of vision related to the central “hump” in the lens design, progressive myopia in 30 % of cases and an occasional Z syndrome 1 . Only a few—if any—eye surgeons in Singapore are still implanting this once lauded lens. This serves as a cautionary tale for surgeons wishing to try a new lens based on information and data solely provided by the manufacturer of the lens or a study funded by the same manufacturer. Take these with a pinch of salt! One needs to firstly assess the lens design on its own merits and decide for oneself if the science is sound and the design practical; then and only then should the opinions and reports of honest, evidence-based practitioners be sought. The Synchrony lens is a complex design that has been shown to have movement within the eye, unlike some other accommodative IOLs. It requires a precise 5 mm capsulorhexis and a larger incision for implantation. We await the FDA results with interest. The most popular presybopia correcting implants today are the pseudoaccommodative group of lenses manufactured by Alcon, AMO and Zeiss. While they all do a good job in delivering good near, intermediate and distant vision, they have limitations as far as dim light performance goes and quality of vision issues when compared to monofocal IOLs. The fact that many patients accept these compromises in exchange for a greater than 90% chance of total spectacle freedom should not distract us from seeking out better and, hopefully, cheaper alternatives. Reference 1. Loh R, Chee SP, Yeoh R. Visual performance of an accommodative IOL implant in an Asian population. Presented at the ASCRS meeting in Boston, 9-14 April 2011. Editors’ note: Dr. Yeoh has no financial interests related to his comments. that it is critical that the lens haptics be positioned properly at the time of implantation. He suggested using a lens hook to move the Tetraflex nasally and temporally to make sure the haptics fully unfold in the capsular bag. In terms of quality of vision, in the clinical trial Dr. Dougherty found that 75% of patients were completely reading glasses independent or only minimally dependent in low light or for fine print. His patients are currently achieving about 0.5 to 1.0 D of accommodation with the Crystalens, but it is estimated that patients will achieve approximately 1.5 D of accommodation with the Tetraflex. “The main upside of this accommodating lens is the quality of vision; it’s spectacular,” he said. “There are less glare, halos, and contrast sensitivity issues than with multifocals. The downside is the percentages of patients reading at the 20/20 [6/6] or 20/25 [6/7.5] levels are not as high. The multifocals give crisper near vision, but there are visual side effects.