Intraocular lens power calculation in keratoconic eyes

Session Details

Session Title: Cataract Surgery Special Cases

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

Paper Time: 08:00

Venue: Auditorium C6

First Author: : J.Reddy INDIA

Co Author(s): :    P. Kumar   A. Mohamed   P. Vaddavalli              

Abstract Details

Purpose:

To evaluate the role of keratometry in intraocular lens (IOL) power calculation using SRK-T formula for cataract surgery in patients with mild, moderate and severe Keratoconus.

Setting:

Tej Kohli Cornea Institute, L V Prasad Eye Institute, Hyderabad, India.

Methods:

In this prospective study, patients with a clinical and topographic diagnosis of Keratoconus were included for evaluation. Past history of contact lens wear or intraocular or corneal surgery was excluded. All patients underwent a comprehensive eye check-up followed by keratometry (K) assessment using manual method, corneal topography with single Scheimpflug Imaging (SimK, True Net Power) and Lenstar. IOL power was calculated using SRK-T formula for all K-values and also using Standard-K (43.25 D). Similar assessments were performed in a control group consisting of patients undergoing cataract surgery without any ocular co-morbidity.

Results:

Keratoconus subjects were divided into mild (31 eyes of 28 patients), moderate (30 eyes of 28 patients) and severe (30 eyes of 27 patients). Thirty-three eyes of 33 patients served as controls.The IOL power calculated in mild, moderate and severe keratoconus ranged from 17.06±3.82D to 18.87±3.41D, 9.87±5.67D to 14.93±3.78D and -3.50±4.02D to 3.05±6.50D respectively and was significantly (p≤0.03) different from the ideal IOL power (20.86±1.96D) calculated in controls. The calculated IOL power in keratoconus was significantly dependent on the severity of disease (p<0.0001). Calculation of IOL power using Standard-K in Keratoconus gave results comparable to ideal IOL power (p>0.05).

Conclusions:

In Keratoconus, IOL power calculated using Standard-K value appears to be approximating the ideal IOL power. The various keratometry techniques underestimate the IOL power calculation in Keratoconus which worsens with the increasing severity of disease.

Financial Disclosure:

NONE