Ablation depth correlates to temporary decrease in corneal sensitivity post-LASIK

GOIAS, Brazil – The depth of the ablation during LASIK may play an important role in the temporary decrease of corneal sensitivity and its recovery, according to surgeons here with Goiânia Eye Institute.

Belquiz A. Nassaralla, MD, PhD, and colleagues compared 102 myopic eyes of 58 patients who underwent LASIK. The eyes were divided into four groups: Group 1 had myopia ranging from –0.75 D to –3.75 D, group 2 had myopia from –4 D to –7.75 D, group 3 had myopia from –8 D to –11.75 D and group 4 had myopia between –12 D and –16 D. Corneal sensitivity was measured several times postoperatively, on days 1, 7, 30, 90, 180, 270 and 365.

Immediately after surgery, the lenticule was completely anesthetic, the study authors wrote in the March issue of Ophthalmology. Full patient recovery varied according to the depth of the ablation, they added.

Corneal sensitivity improved, but was not considered “fully recovered” in groups 1 and 2 after 90 days and in groups 3 and 4 after 180 days.

“Corneal denervation has been implicated in dry eye symptoms after LASIK, and our results have intriguing implications for the potential risk for such symptoms after LASIK for persons with varying degrees of error,” the authors wrote. “If indeed LASIK-related dry eye symptoms are a form of neurotrophic corneal epithelial disease, then our study would suggest that patients with higher error would be at increased risk for dry eye symptoms.”