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The influence of keratometry on visual and refractive outcomes after myopic laser in situ keratomileusis

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Session Details

Session Title: LASIK: Flap Morphology and Ablation Profile

Session Date/Time: Monday 09/10/2017 | 08:30-10:20

Paper Time: 10:10

Venue: Room 3.6

First Author: : S.Frazão PORTUGAL

Co Author(s): :    P. Rodrigues   S. Cruz   A. Carvalho   J. Maia Soco   H. Nogueira        

Abstract Details


To evaluate the effect of preoperative and postoperative keratometry on visual acuity and refraction after Myopic LASER in Situ Keratomileusis (LASIK).


Instituto de Oftalmologia Dr. Gama Pinto, Lisbon, Portugal.


A retrospective study enrolling clinical records of 482 eyes of 275 patients with myopia who underwent LASIK between 2009 and 2016. Subjects were grouped according to the degree of preoperative mean keratometry, into three groups: Group 1 (Flat Cornea): K≤42.00D; Group 2: 42.0046,00; Group 3 (Steep Cornea): K≥46,00D. To evaluate the prognostic impact of keratometry in Myopic LASIK, we considered the results measured at 6 months postoperatively, including visual acuity without correction (VA), postoperative sphere, cylinder, spherical equivalent (SE) and its variation.


The mean preoperative SE was -3,91 ± 1,54D, ranging between -0,88 to -9,38D. The percentage of eyes achieving a postoperative SE ±0,50D was 39,5%, 31,8% and 26% in groups 1,2 and 3 respectively. Moreover, in group 3, 14,3% of the eyes had a residual SE of -2.00D or greater, contrasting with the groups 1 and 2 where only 6-7% of eyes were left with this degree of undercorrection. Concerning visual acuity, eyes achieving 20/25 or more were 81,5%, 81,8% and 71,5%, and 20/50 or less were 6,7%, 6,2% and 11,7% in groups 1,2 and 3 respectively.


There is a significant statistical correlation between the variation in keratometry and spherical equivalent after LASIK (R= 0.51 p<0.01). Myopic Eyes with steeper corneas appeared to have greater tendency to undercorrection, comparing to other degrees of keratometry, presenting worse visual outcomes.

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