Myopia Research Today is a free monthly online journal that collates and summarizes the latest research about Myopia, including details on treatment, prevention, causes, correction.

Corneal sensation after myopic and hyperopic LASIK: clinical and confocal microscopic study.

Bragheeth MA, Dua HS

Division of Ophthalmology and Visual Sciences, University of Nottingham, UK.

AIM: To assess the long term (1 year) effect of myopic and hyperopic LASIK on corneal sensation and innervation. METHODS: 83 eyes of 43 patients having LASIK were evaluated. According to the preoperative spherical equivalent, the eyes were divided into three groups: group 1, myopia from -0.75 to -6.00 D; group 2, myopia from -6.25 to -11.50 D; and group 3, hyperopia from 1.25 to 5.00 D. Corneal sensation was measured and in vivo confocal microscopy (IVCM) was done at the central cornea before, and at 1 month, 3 months, 6 months, and 1 year after LASIK. RESULTS: The mean corneal sensation in group 1 was greater than in groups 2 and 3 at all postoperative measurements. The difference between group 1 on one hand and groups 2 and 3 on the other hand was statistically significant at 1 month and 3 months after LASIK and was not statistically significant afterwards. IVCM study of 27 eyes revealed that the number and length of nerve fibre bundles in the sub-basal region decreased after LASIK and was significantly lower at all times after surgery despite the return of corneal sensation to preoperative level. CONCLUSION: After LASIK, central corneal sensitivity is decreased for as long as 6 months or more. The results suggest that lamellar cutting of the cornea during LASIK impairs corneal sensitivity and is related to the ablation depth. The diameter of ablation too may contribute to this drop in sensitivity. The return of corneal sensations does not directly correlate with the regeneration of nerve fibres as determined by confocal imaging. Sensations return to normal values before complete restoration of normal innervation if this indeed ever occurs.

Published 18 April 2005 in Br J Ophthalmol, 89(5): 580-5.
Full-text of this article is available online (may require subscription).

© 2004-2008 Myopia Research Today. All Rights Reserved.