Change in corneal sensitivity and corneal nerve after cataract surgery

Purpose: To compare corneal sensitivity and recovery of corneal innervation between temporal and superior clear corneal incisions in cataract surgery. Methods: We compared the change in corneal sensitivity in patients with cataract who had received phacoemulsification using either temporal clear corneal incisions (group 1) or superior clear corneal incisions (group 2). The changes were measured at 1 week, 1 month, and 3 months after surgery using the Cochet-Bonnet esthesiometer. For a different study population, changes of corneal sensitivity in 25 eyes of 20 patients and corneal nerve density with confocal microscopy in 20 eyes of 20 patients who had undergone cataract surgery were also assessed. All parameters were measured preoperatively and at 1 week, 1 month, and 3 months after surgery. Results: There was a significant decrease in sensitivity at the incision site in both groups. At 3 months after surgery, corneal sensitivity mostly recovered to preoperative values. Although postoperative change in corneal sensitivity showed similar patterns in both groups, group 1 showed a larger decrease. At temporal clear corneal incision sites, there was significantly decreased sensitivity at 1 week and 1 month postoperatively. However, corneal sensitivity returned to the preoperative levels by 3 months. Confocal microscopy revealed that at 1 week, 1 month, and 3 months after cataract surgery, subbasal nerve density was significantly reduced to 4113 ± 1421, 3555 ± 1448, and 4198 ± 1239 μm/mm, respectively. Conclusions: Corneal sensitivity after cataract surgery returned to near preoperative levels by 3 months before complete restoration of normal corneal innervation. Regeneration of subbasal nerve fibers determined by confocal microscopy seems to require more time than the return of corneal sensation after cataract surgery.