Abstract
Purpose :
To evaluate the impact of scleral lens size and scleral lens wear duration on the intraocular pressure (IOP) of the central cornea and sclera.
Methods :
Subjects presenting with no active ocular diseases were recruited for this randomized and crossover study. Each subject wore bilaterally scleral lenses of fluorosilicone acrylate material with two lens diameters (15.6mm and 18.0mm) for 5 hours on two separate days. IOP was measured with the pneumotonometer (Model 30TM, Reichert Technologies, Inc., Buffalo, New York) at the central cornea before and after scleral lens wear, and at the superotemporal sclera 4mm from the limbus before, after, and during 5 hours of scleral lens wear. The primary outcome measure was the change from baseline (i.e., pre-lens insertion) scleral IOP at four predetermined time intervals: 1) immediately after lens insertion, 2) 2.5-hr post-lens insertion, 3) 5-hr post-lens insertion, and 4) immediately after lens removal. Diurnal variations of each subject’s corneal and scleral IOP were also determined at a separate day without lens wear.
Results :
Seventeen subjects with mean (SD) age of 26.1 (8.5) years completed the study. There was no significant diurnal variability of both IOPs during the 5-hour visit without lens wear (p>0.05). The mean [95% CI] changes of corneal IOP after 5 hours of wear for 15.6 mm and 18.0mm lenses were -0.3 [-0.7, 0.1] mmHg and 0.0 [-0.6, 0.6] mmHg, respectively. Both lens diameters did not affect the corneal IOP after 5-hr lens wear (p>0.05). The mean [95% CI] changes of scleral IOP were 0.9 [0.2, 1.6] mmHg immediately after lens insertion, 1.6 [0.8, 2.3] mmHg after 2.5-hr lens wear, 1.1 [0.4, 1.9] mmHg after 5-hr lens wear, and 0.2 [-0.4, 0.8] mmHg immediately after lens removal with small-diameter lenses, compared with -0.1 [-1.0, 0.8] mmHg, 1.4 [0.5, 2.3] mmHg, 0.8 [0.0, 1.6] mmHg, and -0.2 [-1.0, 0.6] mmHg with large-diameter lenses. Both lens diameters did not affect the scleral IOP after 5 hours of wear (p>0.05). However, 73.5% of the scleral IOP measurements increased at 2.5 hours after lens insertion with 15.6mm lenses (p=0.021) and with 18.0mm lenses (p=0.074).
Conclusions :
The intraocular pressures of healthy eyes restored to the baseline values after 5 hours of scleral lens wear. The smaller scleral lens size induced a statistically but not clinically signficiant increase in scleral IOP at 2.5 hours after lens insertion.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.