Abstract
Purpose :
Tear exchange beneath rigid contact lenses helps to supply the cornea with the oxygen required for normal corneal metabolism. Studies of short-term wear of scleral lenses (SLs) in healthy volunteers have suggested that minimal tear exchange occurs during SL wear. The purpose of the present study was to document tear exchange in established SL wearers.
Methods :
Established SL wearers (≥ 6 months of wear) were recruited for this study during routine follow-up evaluations. All participants had worn their SLs for at least 2 hours prior to their study visits. Demographic data and landing zone (LZ) design for each lens was recorded. Sodium fluorescein (NaFl) was instilled over the lens in each eye. Presence or absence of NaFl in the post-lens fluid reservoir (FR) was recorded 10 seconds, 1 minute, 2.5 minutes, and 5 minutes after instillation. Differences between NaFl uptake into the FR between different lens designs and diameters were compared using Chi-squared tests.
Results :
30 established SL patients (53 eyes) with a were recruited (mean age of 46 ± 14.6 years (range 24-76)). Mean duration of lens wear prior to study visit was 4.8 ± 2.1 hours (range: 2.1-10 hours). Twenty-seven lenses (50%) had quadrant-specific LZ, 18 (34%) had toric LZ, and 8 had spherical LZ. Overall, NaFl was observed in the FR in 9 eyes (17%) at 10 seconds, 14 eyes (26.4%) at 1 minute, 25 eyes (47.2%) at 2.5 minutes, and 33 eyes (62.3%) at 5 minutes. With quadrant-specific LZ (n=25), NaFl was observed in the FR in 4 eyes (14.8%) at 10 seconds, 5 eyes (18.5%) at 1 minute, 11 eyes (40.7%) at 2.5 minutes, and 14 eyes (51.9%) at 5 minutes. With toric LZ (n=18), NaFl was observed in the FR in 3 eyes (16.7%) at 10 seconds, 7 eyes (38.9%) at 1 minute, 12 eyes (66.7%) at 2.5 minutes, and 15 eyes (83.3%) at 5 minutes. With spherical LZ (n=8), NaFl was observed in the FR in 2 eyes (25%) at 10 seconds, 1 minute, and 2.5 minutes and in 4 eyes (50%) at 5 minutes. No significant differences were noted between any LZ design at any time point (p=0.8, 10 seconds; p=0.3, 1 minute; p=0.08, 2.5 minutes; p= 0.09, 5 minutes).
Conclusions :
Tear exchange occurs beneath SLs in a majority of established wearers. Neither lens diameter nor LZ design were associated with an increased likelihood of tear exchange in this sample.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.