Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) causes corneal epithelial thinning without altering overall corneal thickness or hysteresis

Abstract

Purpose: To assess the effect of the Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) wear on corneal epithelial thickness, total corneal thickness, and corneal hysteresis.

Methods: This was a prospective study of all patients referred for PROSE treatment at Weill Cornell Ophthalmology. 32 eyes (16 patients) treated with extended PROSE wear, defined as more than 6 hours per day for longer than 30 days, were included in the analysis. Each eye had corneal hysteresis measurements taken with the Ocular Response Analyzer (Reichert, Inc, Buffalo, NY) and Visante anterior segment OCT (Carl Zeiss International, Oberkochen, Germany) at 90 and 180 degrees during the initial visit before PROSE wear and after extended PROSE wear. Epithelial and central corneal thickness were determined using Neurolucida software (MBF Bioscience, Williston, VT) with the quick measure line tool. Corneal hysteresis, central corneal thickness, and epithelial thickness before PROSE wear and after 30 days of more than 6 hours of daily PROSE wear were compared using a paired t-test for means.

Results: Corneal epithelium was significantly thinner after PROSE wear (32.11 +/- 4.24 μm) than before (35.11 +/- 5.5 μm) extended PROSE wear (p=0.13). Central corneal thickness was unaltered by extended PROSE wear (492.36 +/-22.6 μm vs. 488.93 +/- 27.7 μm, p=0.385). Corneal hysteresis, a test of corneal biomechanics, was also not significantly different before and after extended PROSE wear (9.05 +/- 2.6 mmHg vs. 9.74 +/- 2.79 mmHg, p=0.249).

Conclusions: Patients had thinner corneal epithelium after a period of extended PROSE wear. This thinning may represent morphologic changes to the corneal epithelium after extended exposure to the PROSE fluid reservoir and lack of exposure to air. However, the lack of air exposure did not effect other corneal physical properties, including central corneal thickness, and corneal hysteresis.

Keywords: 482 cornea: epithelium • 479 cornea: clinical science • 477 contact lens