Introduction

To evaluate the cases of posterior corneal ectasia following laser in situ keratomileusis.

Material and methods

Thirteen eyes of 7 patients, that were diagnosed to have posterior corneal ectasia (ł0.060mm) on Orbscan topographic system following LASIK, were identified. The parameters evaluated were uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refraction, contrast sensitivity, glare, corneal topography, keratometry and pachymetry. The preoperative and postoperative data at day 1, 1 week, 1 month, 3 months, 6 months and 1year were retrospectively analyzed.

Results

The mean UCVA of the patients before LASIK surgery was 0.032 ± 0.04. It was 0.320 ± 0.159 in follow- up of LASIK surgery after 1 year. The mean Pre-LASIK BCVA was 0.59 ± 0.11. There was no change in mean BCVA at 1 year. The mean preoperative spherical equivalent was -14.25 ± 2.91 D except in 2 hyperopic eyes in which the mean spherical equivalent preoperatively was +5.75 ± 0.35 D. The mean postoperative spherical equivalent after 1 year of LASIK surgery in last follow-up (± enhancement) was - 3.45 ± 2.08 in the myopic eyes and +1.0 ± 0.70 in the two hyperopic eyes. The mean preoperative posterior corneal elevation was 0.022 ± 0.011mm, which at the end of 1 week following LASIK was 0.067 ± 0.009 and at 1 year/ last follow-up following LASIK, it was 0.068 ± 0.006mm.

Conclusions

Higher amplitudes of refractive correction may lead to the occurrence of posterior corneal ectasia.