EyeWorld India September 2017 Issue

EWAP FEATURE 15 September 2017 which compares favorably to pene- trating keratoplasty. A larger percent- age of patients enjoy uncorrected visual acuities in the 20/20 to 20/25 range. However, I think it would be unwise to view the Athens protocol as a refractive procedure aiming for emmetropia. Topography-guided PRK should aim to normalize the cornea and address potential significant anisometropia at a later time, either with a phakic intraocular lens or with a lens-based procedure, such as clear lens extraction or cataract surgery with a multifocal, toric, or extended depth of focus intraocular lens. Since this technique has been introduced, it has become one third of my clinical practice and has re- duced my cornea transplantation rate by 90%,” he said. Treat irregular corneas before cataract surgery According to Dr. Kanellopoulos, many surgeons have previously used toric lenses in patients with ir- regular corneas and have achieved a relatively good visual result. “I, nev- ertheless, think that in these cases, the optimal approach would be to first normalize the cornea and give that eye the ability to become the best possible lenticular system for a cataract procedure to come at a later time, perhaps 2 or 3 months later. At that time, intraocular lens calcula- tion would be far more accurate and the use of a premium intraocular lens, such as a multifocal, extended depth of focus, or a toric IOL, may address visual rehabilitation better, despite the fact that this would be two procedures. I think that doing the cataract procedure first and then trying to normalize the cornea if the patient was symptomatic would be far more difficult,” he said. Other options According to Dr. Donnenfeld, if patients are not candidates for topography-guided PRK or wave- front aberrometry, the cone can be flattened using phototherapeutic keratectomy with the excimer laser. “This flattens the cone and uses the epithelium to prevent ablation in the flatter areas, while the cones that have thinner epithelia over their surface ablate more rapidly. Very commonly, this can flatten the cone by up to 5 D. We have fol- lowed this procedure with a topo- graphic ablation several months later,” he said. Finally, for patients who are not candidates for excimer laser, cor- neal inlays are helpful in improving cones. “We find this particularly helpful in patients with thin inferi- orly displaced cones, as with pellu- cid marginal degeneration. In sum- mary, there is a whole new world of technologies that allow the corneal surgeon to improve the vision in patients with irregular corneas to dramatically improve their quality of vision as well as their quality of life,” Dr. Donnenfeld said. EWAP References 1. Kanellopoulos AJ. Comparison of sequential vs same-day simultaneous collagen cross-linking and topography- guided PRK for treatment of keratoconus. J Refract Surg. 2009;25:S812–8. Editors’ note: Drs. Donnenfeld and Kanellopoulos have financial interests with Alcon. Dr. Stein has no financial interests related to this article. Contact information Donnenfeld: ericdonnenfeld@gmail.com Kanellopoulos: ajkmd@mac.com Stein: raymondmstein@gmail.com Hill-RBF Method The Hill-RBF Method is a complete new approach for IOL power selection. RBF stands for Radial Basis activati- on Function. The calculation is driven by an advanced, self-validating method using pattern recognition based on artiƂcial intelligence and sophisticated data interpo- lation. EyeSuite IOL The Hill-RBF Method is included exclusively in the latest EyeSuite software. In addition to the new calculator, Eye- Suite provides state of the art IOL calculation formulae such as Olsen, Barrett’s Universal II, True K and Toric Cal- culator. Up to 12 formulae are eligible in a user-friendly interface to match any surgeons demandings. www.haag-streit.com LENSTAR LS 900 Improving outcomes ADV_Hill-RBF_EyeWorldAsia_25-07-2017.indd 1 26.07.2017 13:50:23