Toric intraocular lens calculation results using different devices and methodology

Session Details

Session Title: Toric IOLs

Session Date/Time: Sunday 14/09/2014 | 16:30-18:30

Paper Time: 18:09

Venue: Capital Hall B

First Author: : O.Reitblat ISRAEL

Co Author(s): :    G. Kleinmann   A. Levy   Y. Ton   A. Abulafia   E. Assia  

Abstract Details

Purpose:

To compare different measuring devices in toric intra-ocular lens (IOL) calculations with and without posterior corneal curvature consideration.

Setting:

Ein-Tal Ophthalmology Center, Tel Aviv, Israel.

Methods:

Consecutive cases with a toric IOL implantation and preoperative measurements using optical biomety (IOLMaster-500 and Lenstar-LS900) and Scheimpflug Camera (Pentacam) were reviewed. Different methods were compared in a theoretic selection of a toric IOL: (1) anterior corneal astigmatism using the IOLMaster, Lenstar and Pentacam; (2) vector subtraction of the posterior corneal astigmatism measured by the Pentacam from anterior corneal measurements; (3) Scheimpflug Camera’s true net corneal power. A toric IOL astigmatic power and axis, estimated to produce the lowest residual astigmatism, were selected according to each method. Based on manifest refraction > 1 month following surgery, simulated residual refraction was calculated for each method.

Results:

50 eyes, of 42 patients, operated by two surgeons, were enrolled in the study. Using anterior corneal measurements with the IOLMaster, Lenstar and Pentacam, 36%, 38% & 36% of eyes had residual simulated astigmatism within ≤0.5D, 64%, 60% & 58% within ≤0.75D, and 84%, 86% & 76% within ≤1.0D, respectively. Combining posterior topography showed better results with 48%, 40% & 30% within ≤0.5D, 74%, 72% & 68% within ≤0.75D, and 92%, 94% & 78% within ≤1.0D, respectively. Residual astigmatism with Pentacam’s total corneal power was 32%, 66% & 86% within ≤0.5D, ≤0.75D and ≤1.0D, respectively. IOL selection was in agreement according to the IOLMaster and the Lenstar in 64%. The IOL alignment based on the two devices was within 5° deviation in 68%. Integration of the posterior surface curvature changed IOL toricity in 54% and 62% respectively, and changed the axis in more than 5° in 14% with both devices.

Conclusions:

The IOLMaster and the Lenstar showed similar residual astigmatism results, which were lower than Pentacam’s anterior residual astigmatism. Accounting for the posterior corneal astigmatism reduces further residual astigmatism compared with anterior cornea alone.

Financial Interest:

NONE