Abstract
Purpose: :
To evaluate the relations between pre operatory topografic and aberrometric findings and the post operative outcomes in patients with Keratoconus treated with Intrastromal rings (kerarings) implanted with Intralase.
Methods: :
To evaluate the association between the change of visual acuity in logMAR after the procedure and the following independent variables: Kmax, Vertical Coma and spherical aberration (before treatment), generalized estimating equation (GEE) models were performed to account for the dependence between eyes. In a cumulative logit GEE model, success defined as Mean Toric Keratometry (TKM) equal or less then 48 diopters and the same independent variables of the fist model were tested.
Results: :
This study evaluate 18 eyes of 15 patientes with a mean age of 29 ± 10 years. The mean interval between pre and post operative examinations was 72 ± 48 days. The mean pre operative curvature (Kmax) was 51,65 ± 2,80 D and the Mean pre op TKM was 52.51 ± 3.59. The post operative values decreased after Keraring implantation (-7.91 ± 12.36) with a improvement in post operative CDVA pre from 0.74 ± 0.66 to 0.43 ± 0.29 ( difference -0.38 ± 0.56). There was a inverse correlation (Wald Chi-Square P<0,005) between the K Max and the improvement is CDVA while no significant correlation was found in pre op vertical coma -2.57 ± 1.74 or spherical aberration -0.60 ± 0.73. None of the tested variables were significantly associated with the TKM definition of success.
Conclusions: :
The K max had a inverse correlation with the visual outcome after keraring implantation indicating limitations in patients with high pre operative values of keratometry as predictor for poor results.
Keywords: keratoconus • topography