Abstract
Purpose :
We have developed a dexamethasone (Dex)-eluting contact lens (Dex-CL) that provides sustained dexamethasone release for 7 days. The purpose of this study was to assess repeated use of Dex-CLs in normal eyes for known Dex and CL side effects (corneal edema and epithelial defects), along with potential effects from systemic drug exposure (weight loss).
Methods :
New Zealand White rabbits (n=4, 2 male and 2 female per group) wore Dex-CLs or commercial contact lenses (CCLs) composed of the same methafilcon hydrogel with the same lens dimensions (base curve and diameter). The lenses were replaced every week for four consecutive weeks. During the study, slit lamp imaging and anterior segment ocular coherence tomography were performed weekly to assess corneal health. Fluorescein-staining from slit lamp photos were graded by two masked cornea experts using the NEI cornea scale. Intraocular pressure (IOP) and body weight were also monitored weekly to assess for known ocular and systemic Dex side effects. Blood was collected after 4, 8, and 24 hours, 3 days and 7 days of Dex-CL wear to determine the serum Dex concentrations; levels were compared to serum obtained after application of hourly 0.1% Dex drops given for 8 hours. Statistical comparisons were done with Student t-test.
Results :
Central corneal thickness increased with CCL more than with Dex-CL at 1 week (79±28 vs +10 ±24 µm, p=0.007) and 4 weeks (108±10 vs 16±41 µm, p=0.014). There were no significant differences in IOP or body weight between the two groups throughout the study. No signs of animal distress were observed. The average corneal staining score was minimal for both groups and tended to decrease compared to baseline staining prior to lens wear, but this difference was not significant. Hourly Dex drops results in higher serum drug concentrations (Cmax=24.0±10.4 ng/mL) than Dex-CLs at most time points: 4 hours (5.8±3.1, p=0.01), 8 hours (14±2, p=0.09), 1 day (12±2, p=0.06), 3 days (2.2±1.8, p=0.004), 7 days (undetected).
Conclusions :
No ocular or systemic adverse effects were observed with Dex-CL after 28 days of wear. The eluted Dex may have a protective effect against corneal edema that can be caused by contact lens wear.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.