Preliminary validation of an optimized algorithm for intraocular lens power calculation in keratoconus

Session Details

Session Title: Cataract Surgery Special Cases

Session Date/Time: Monday 12/09/2016 | 08:00-10:30

Paper Time: 08:06

Venue: Auditorium C6

First Author: : R.Pérez Cambrodí SPAIN

Co Author(s): :    D. Piñero Llorens   V. Camps   E. Caravaca Arenys   D. de Fez   J. Ruiz Fortes   R. Soto Negro     

Abstract Details

Purpose:

To evaluate the theoretical influence on IOL power (PIOL) calculation of the use of the keratometric approach for corneal power (Pc) calculation in keratoconus and to develop and validate preliminarily an algorithm to minimize this influence

Setting:

Grupo de Óptica y Percepción Visual (GOPV). Department of Optics, Pharmacology and Anatomy. University of Alicante, Spain. Department of Ophthalmology (OFTALMAR), Vithas Medimar International Hospital, Alicante, Spain

Methods:

Pc was calculated theoretically with the classical keratometric approach, the Gaussian equation and the keratometric approach using a variable keratometric index (nkadj) dependent on r1c (Pkadj). Differences in PIOL calculations (APIOL) using keratometric and Gaussian corneal power values were evaluated. Preliminary clinical validation of a PIOL algorithm using Pkadj was performed in 13 keratoconus eyes

Results:

PIOL underestimation was present if Pc was overestimated, and vice versa. Theoretical PIOL overestimation up to -5.6 D and -6.2 D using Le Grand and Gullstrand eye models were found for a keratometric index of 1.3375. If nkadj was used, maximal APIOL was ±1.1 D, with most of values ≤ ±0.6 D. Clinically, PIOL under and overestimations ranged from -1.1 to 0.4 D. No statistically significant differences were found between PIOL obtained with Pkadj and Gaussian equation (p>0.05).

Conclusions:

The use of the keratometric Pc for PIOL calculations in keratoconus can lead to significant errors that can be minimized by using a Pkadj approach

Financial Disclosure:

NONE