EyeWorld India March 2017 Issue

52 EWAP DEVICES March 2017 Views from Asia-Pacific Dandapani RAMAMURTHY, MD Chairman, The Eye Foundation 582-A, D.B. Road, Coimbatore 641002, India Tel. no. +91-422-4242000 Fax no. +91-422-4242099 drramamurthy@theeyefoundation.in O ur confidence in multifocal IOLs increased with the introduction of diffractive presbyopia correcting IOLs. The diffractive IOLs no longer created alternate zones of distance and near, but each step of the diffractive multifocal IOL now contributed to both distance and near. Hence you could also call these lenses “pupil independent”, though in a limited sense of the term. Of special mention among these diffractive lenses is a lens with the technology of apodization. The diffractive steps of this lens tapered down from the center to the periphery of the diffractive steps, allowing for increased efficiency of light management between the two focal points, according to the lighting environment to which the patient is exposed to. Apodization made the lens more distant dominant, thereby improving the distance image quality even in low light. However, one clear area of research still remains. How do we provide great intermediate vision to our patients without dropping the image quality of the near and the distance? The first generation trifocal lenses on a hydrophilic platform were launched a couple of years ago. These lenses provided good intermediate vision at a distance of 80 cm from the eye. The patient now gets not only good near and distance, but can easily work on the computer without the help of glasses for the intermediate. Recently, we have witnessed the launch of a new trifocal IOL from Alcon in some markets in Asia. This lens is the first trifocal IOL on the hydrophobic platform. The manufacturer claims that the lens provides comfortable intermediate vision at a distance of around 60 cm from the eye. Personally, I have noticed that patients are more comfortable working on their laptops at arms-length, which would be near about 65 cm for the average patient. One of the biggest challenges of the present generation of trifocal IOLs is to provide intermediate without dropping the image quality of the near and distance. To this end, a trifocal IOL which utilizes more light would be at a clear advantage because it is the light that is lost that causes dysphotopsia. The new trifocal introduced by this company is claiming to use a higher percentage of light at an average pupil diameter of around 3 mm. The extended depth of vision IOL (Symfony, AMO) works on a completely different principle having not two precise foci and also reducing the amount of chromatic aberration. So now we have the freedom of choice: Diffractive multifocals, low add, EDOV, trifocals. The fact that all of them have a market share is testimony that none of them is perfect. That being said, we should always put the horse before the cart. The role of ophthalmologists in selecting the right patient with adequate preoperative evaluation and counseling cannot be overemphasized. Modern day biometry machines using laser interference biometry, improved formulae such as the Barrett Universal formula or the Hill RBF, new age aberrometry, OCT of the macula and dry eye tests are all helpful in the armamentarium for selecting the right patient for optimal outcomes. Editors’ note: Dr. Ramamurthy is a consultant for Alcon and AMO. John CHANG, MD Hong Kong Sanatorium and Hospital 4/f, Li Shu Fan Block, 2 Village Road, Happy Valley, Hong Kong Tel. no. +85-2-28358885 Fax no. +85-2-28358887 johnchang@hksh.com I n Hong Kong, we have the AT LISA trifocal, PanOptix, FineVision and Symfony EDOF. Trifocal lenses are definitely the lens of choice because it gives intermediate vision also. However, for near vision, they are not as strong as the bifocal, especially the Tecnis (+4 D). It is extremely important to determine the needs of the patient. In Hong Kong and most Asian cities, patients have shorter stature and therefore read at a much closer distance than Caucasians. They don’t drive, so halo and glare is much less of an issue. Bifocal (+4 D) is ideal for them. However, they should still be warned about the possibility of halo (74%), glare (81%), and waxy vision. 1 Trifocals have less halo, glare, and waxy vision. Among the trifocals, PanOptix IOLs have the least visual symptoms. Symfony lenses have even less, but its near is weakest. Therefore, we usually recommend them to patients who have more intermediate demands, e.g., office workers, housewives for cooking, and patients who do occasional computer work or don’t read much. Trifocals have the least tolerance for astigmatism (up to 0.75 D), so accurate biometry, IOL calculation, and surgical technique are very important. Bifocal IOLs tolerate up to 1.0 D and EDOFs up to 1.5 D of astigmatism. For people who drive and are concerned about visual symptoms, we recommend the EDOF and use monovision, although there have been some reports of significant visual symptoms also. If they have problems with the Symfony, they will have much worse symptoms with the trifocal and bifocal. There is no doubt that neuroadaptation does occur. We have patients implanted with bifocal lenses who complain of significant halo and glare initially, but since they were warned about this before surgery, and most of their friends have had this implanted and had reported improvement in symptoms, very few ask for lens exchange nowadays, and after 1-2 years they are no longer bothered by these dysphotopsias. Dry eyes must be addressed. If there is corneal stippling, they should be treated before the lens is implanted. I look very carefully at the macula, and if in any doubt, an OCT should be advised to avoid embarrassment if an epiretinal membrane is found after surgery. I usually stay away from these lenses if patients have drusen or are diabetic. If their diabetes is very well controlled, I have a lengthy discussion with them so they know what they are in for. Trifocals are very promising and I am using them more and more especially if patients don’t need strong near or their astigmatism is not too strong. Reference 1. Chang JS, Ng JC, Chan VK, and Law AK. Visual outcomes and patient satisfaction after refractive lens exchange with a single-piece diffractive multifocal intraocular lens. J Ophthalmol . 2014;2014:458296. Editors’ note: Dr. Chang declared no relevant financial interests. Trifocals - from page 51