Extended wear of fluid-filled scleral contact lenses may change corneal nerve function in patients with certain diseases, according to research published in the April 2015 Cornea.1
Researchers measured tear production, central corneal sensation, sub-basal nerve density and tortuosity, and stromal nerve thickness of 20 patients from the Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) treatment program. Patients were divided into two groups—distorted corneas (DC) or ocular surface disease (OSD)—and evaluated before and after 60 days of wear for a minimum of eight hours per day.
Researchers found basal tear production significantly decreased and corneal sensation increased in patients with DC following long-term wear of the PROSE prosthetic device. In contrast, tear production and corneal sensation did not change in patients with OSD. This difference, the researchers say, may be because patients with DC have a healthier ocular surface; thus, the intact lacrimal functional unit (LFU) “responds to the constant saline exposure by reducing the basal tear production and increasing corneal sensation, which are possible signs of improvement in corneal disease.” In contrast, “patients with OSD did not have similar alterations in LFU function possibly because of ongoing inflammatory processes disrupting the LFU.”
No significant change in sub-basal nerve density and tortuosity or stromal nerve thickness was observed in either patient group.
1. Wang Y, Kornberg DL, St. Clair RM, et al. Corneal nerve structure and function after long-term wear of fluid-filled scleral lens. Cornea. 2015 April;34(4):427-32.