Long-term stability of the posterior cornea after laser in situ keratomileusis

Purpose

To study long-term changes in posterior corneal elevation after laser in situ keratomileusis (LASIK) using Scheimpflug topography (Pentacam, Oculus, Inc.) in eyes 1 year after LASIK.

Setting

Department of Ophthalmology, Albany Medical Center, and a private practice, Albany, New York, USA.

Methods

One hundred two myopic eyes of 52 consecutive patients presenting for their 1-year follow-up were prospectively evaluated using the Pentacam to determine elevation changes to the posterior corneal surface between preoperative and 1-year postoperative measurements. Changes in posterior elevation were performed by comparing the best-fit sphere preoperatively and postoperatively with a fixed reference sphere determined by the central 9.0 mm preoperative cornea. Statistical and graphical analyses were performed.

Results

One hundred two post-LASIK eyes (mean correction −4.33 diopters; mean ablation depth 68.70 μm; mean estimated residual bed thickness 327 μm) had a mean posterior displacement of −0.47 μm ± 3.48 (SD) (range −10.0 to +7 μm). The mean follow-up period was 13.6 months (range 8.8 to 19.3 months).

Conclusions

In this population, no patient had significant forward protrusion of the posterior corneal surface a mean of 14 months after LASIK. The posterior cornea in post-LASIK myopic eyes was very stable. Contrary to results in previous studies, progressive changes to the posterior corneal surface did not routinely occur after LASIK performed within established parameters.