Abstract
Purpose: :
To evaluate the recovery of subbasal nerve density and architecture between 5 and 11 years following PRK in human subjects.
Methods: :
Eleven patients, who underwent myopic excimer laser photorefractive keratectomy (PRK, VISX 20/20B) in the early 90’s, were examined using in vivo confocal microscopy 5 (TSCM) and 11 (Confoscan 3) years postoperatively. Eleven (TSCM) healthy unoperated, age–matched individuals served as controls. The length of all nerves/ mm2 was measured together using Adobe Photoshop 7.0 software, to give an estimate of total nerve length/ mm2.
Results: :
The mean length of subbasal nerves /mm2 in controls was 14.17 mm (SD +5,83), 10.17 mm (SD +5,31) at 5 years, and 13.24 mm (SD +5,29) at 11 years postoperatively.
Conclusions: :
The length of corneal subbasal nerves seems to increase even between 5 and 11 years after PRK. Due to the limited number of subjects the result was statistically insignificant. However, knowing the slow recovery of corneal sensitivity after refractive surgery, and the demonstrated continuation of the nerve recovery past the first postoperative year, this finding raises a question about the real recovery potential of peripheral neural tissue.
Keywords: refractive surgery: PRK • microscopy: confocal/tunneling • nerve fiber layer