Abstract
Purpose :
Intra-ocular pressure (IOP) has been shown to increase after 2 to 8 hours of wearing a scleral contact lens (SL). However, cumulative impact on IOP remains unclear. We hypothesize sustained IOP increase will occur during longer-term SL wear, due to continued biomechanical changes induced by the SL on anterior segment structures. This may have ocular health implications, as elevated IOP over extended duration may potentially lead to glaucomatous damage in susceptible individuals. This study investigated the cumulative impact of one week of conventional daily wearing of SLs on IOP.
Methods :
25 healthy adults (25.8 ±3.7 yrs.) having normal corneas participated in this prospective within-subjects study. One eye of each subject was randomly selected for a 16.5 mm diameter best-fit SL. The fellow eye was fitted with a 14.0 mm diameter soft contact lens (SCL) which served as a control. Participants wore both lenses for 8 hours daily for 1 week. IOP measures using iCare tonometry were assessed at morning (AM) and after 8 hours (PM) in three-day visits: the baseline measurement day, initial contact lens wear day, and 1week lens wear day. On the baseline day, no lenses were worn. IOP measures were taken pre-lens wear and immediately post-lens removal in the first and last days of 1 week of lens wear. Paired two-tailed t-tests were used for statistical analysis using Bonferroni correction.
Results :
IOPs from both AM and PM visits for the three days were averaged (Table 1). AM and PM baseline data showed that diurnal variation had no significant impact on IOP in either eye. For the SL eyes, AM and PM IOPs on initial contact lens wear day showed IOP increase (4.02 mmHg; p < 0.001); approximately 30% IOP increase from PM baseline visit. After 1 week of wear, IOP increase with the SL eye was found between the AM and PM visits (3.71mmHg; p < 0.001); 28% IOP increase from PM baseline visit. PM visit IOP increases for the SL eyes on initial contact lens wear day and post-1week lens wear day were not significantly different (p > 0.05). There were no significant IOP changes from baseline in the SCL eyes at any visit (p > 0.05).
Conclusions :
This study demonstrated sustained IOP increase occurred during longer-term SL wear. This IOP increase was of similar magnitude regardless if it was after 1 day or 1 week of SL wear. Potential biomechanical causes are currently being investigated.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.