Abstract
Purpose :
Corneal crosslinking is indicated for progressive pediatric keratoconus to halt its progression. The main parameters used to confirm keratoconus stabilization are visual acuity, maximum keratometry, and pachymetry. The relevance of the posterior surface curvature of the cornea is less understood. The aim of the present study is to describe nine patients with documented progressive keratoconus in whom crosslinking was performed, and subsequent changes on pachymetry, and anterior and posterior corneal surfaces.
Methods :
Clinical and tomographical data from a series of pediatric progressive keratoconus, documented by corneal tomography, were retrospectively collected before, and 3, 6, 12, 18-24 months after crosslinking procedure according to Dresden protocol. Statistics were performed using IBM SPSS Statistics software ( IBM Inc., New York, NY, USA). Normal distribution of the data was confirmed using the Kolmogorov–Smirnov test. Data from mean frontal (RmF) and back (RmB) radii corneal surfaces, thinnest pachymetry, and minimum sagittal radii (RSagMin) changes were analyzed using repeated measures one-way analysis of variance. A p-value < 0.05 was considered statistically significant.
Results :
Nine patients, with a mean age of 14.8 ± 1.9 years old, with a female: male ratio of 6:3 were evaluated. The results of the one-way repeated-measures analyses of variance showed that after crosslinking there was a significant increase on RmF (F=22.2, p=0.002), and decrease on RmB (F=16.5, p=0.004) and thinnest pachymetry (F=36.2, p=0.001). RSagMin values were not statistically different (F=1.895, p=0.25). Pearson correlation coefficient showed an association between pachymetry and RmF (0.860, p=0.003) and between pachymetry and RmB (0.856, p=0.003) before crosslinking.
Conclusions :
In our study, progressive pediatric keratoconus treated with standard crosslinking protocol flattened their frontal corneal surface but kept steeping their back corneal surface associated with an increasing corneal thinning. These data may support the hypothesis that keratoconus keeps progressing on the posterior surface, where crosslinking does not have any effect. More attention should be given to the back corneal surface to indicate that keratoconus is in fact completely halted.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.