Posters

Evaluation of the refractive outcome of cataract surgeries in post-myopic LASIK/PRK eyes following IOL power calculation using two open access online tools

Poster Details

First Author: P.Srivatsa INDIA

Co Author(s):    M. Kurian   S. Das   N. K P   R. Shetty   K. Shetty        

Abstract Details

Purpose:

To evaluate the visual outcome and residual spherical and cylindrical refractive error following cataract surgery in patients post myopic Laser in-situ keratomileusis (LASIK) or myopic photorefractive keratectomy (PRK), without pre-refractive surgical data using the American Society of Cataract and Refractive Surgery (ASCRS) intraocular lens (IOL) power calculator and the Asia-Pacific Association of Cataract and Refractive Surgeons (APACRS) Biometry Calculation post refractive surgery.

Setting:

Department of Cataract and Refractive Services at Narayana Nethralaya Super speciality eye hospital and postgraduate institute of ophthalmology, Bengalore,India

Methods:

Retrospective analysis. Consecutive patients reporting to the hospital for cataract surgery with a previous history of myopic LASIK or PRK without pre- refractive surgical data were included in the study. The patients underwent uneventful phacoemulsification surgery. The IOL power was calculated by: Wang-Koch-Maloney, Shammas No-History, Haigis-L, ASCRS-Average, ASCRS – Min, ASCRS – Max. The expected residual spherical power with the chosen IOL power, the actual stable post-cataract surgery refractive error in terms of the spherical and cylindrical power was evaluated. The APACRS Biometry Calculation post refractive surgery based on Barrett’s true-K formula was back calculated and evaluated.

Results:

24 eyes of 19 patients, 7 males and 12 females with a mean age of 44.47 ± 10.32 years. The average power of the IOL implanted post-cataract extraction was 16.58±4.22 Diopters (D), while the average calculated IOL power was 16.53±4.60 D with a residual spherical error of -0.14±0.37 D. The actual post surgery refractive error was -0.17±0.74 D Sphere and -0.60±0.57 D Cylinder. The average IOL power back calculated using APACRS Calculator in 21 of 24 eyes was 16.5±4.88 D with a residual sphere of -0.002±0.089 D. There was no statistically significant difference between the expected and actual residual spherical error using both the ASCRS calculator (p = 0.70) and the APACRS Calculator. (p = 0.65).

Conclusions:

The ASCRS and APACRS IOL power Calculators are open access online tools and hence are largely used world-wide for calculating the IOL power in the extremely challenging but ever-enlarging population of post- myopic excimer refractive surgery (LASIK/PRK) patients . Despite the significant improvement in their predictive abilities, refractive surprises continue to occur, though reduced in magnitude. Our study helps us to better understand the refractive outcomes following the use of these calculators which in turn will contribute to the improvement of the accurate IOL power selection.

Financial Disclosure:

NONE