LASIK decreases corneal innervation, confocal microscopy shows

ROCHESTER, Minn. — The number of nerve fiber layer bundles in the cornea decreases immediately after LASIK, and in some layers decreases by as much as 90%, researchers here found.

Confocal microscopy revealed that nerve fiber bundles in the subbasal and stromal layers of the cornea decreased by 90% postoperatively, and at 1 year postop their number still remained at less than half that before LASIK.

Researchers here at the Mayo Clinic used confocal microscopy to study 17 eyes of 11 patients who had undergone LASIK to correct myopia of from –2 D to –11 D. In the subbasal region, the number of nerve fiber bundles decreased by more than 90% 1 week after LASIK and were significantly lower than preoperatively at all visits after surgery out to 1 year (P < .001). The number of bundles had increased at 6 and 12 months after LASIK, but they remained at less than half of their preoperative levels. In the stromal flap, the number of nerves at all visits postop were also significantly less than preop levels and did not increase by 1 year postop. The nerve bundles in the stromal bed were not significantly changed.

The study is published in the December issue of Investigative Ophthalmology & Visual Science.