Short-Term Impact of Scleral Lens Wear on Intraocular Pressure and Retinal Nerve Fiber Thickness

Purpose: To investigate the short-term impact of scleral lens wear on intraocular pressure (IOP) and retinal nerve fiber layer thickness (RNFL). Methods: This prospective study included 31 healthy participants aged 26 ± 3 years who were randomly fitted with a 16.5 mm scleral lens over one eye and a soft contact lens on the other eye. IOP and RNFL thickness were examined at baseline in the morning and following 8 hours of scleral and soft contact lens wear in the evening. Two tonometers (a transpalpebral Diaton and a non-contact tonometer) were used to measure IOP. Measurements of IOP and RNFL were taken under four different conditions: pre- and post-lens application, and pre- and post-lens removal. Results: Eyes fitted with a scleral lens exhibited a significant increase in IOP (pre-application: 11± 3 mmHg vs. post-application: 16 ± 4 mmHg, P < 0.001) immediately after scleral lens application, and the increase in pressure was sustained throughout the 8 hours of lens wear (pre-removal IOP: 16 ± 4 mmHg). IOP returned to baseline after scleral lens removal (11 ± 3 mmHg). Eyes fitted with soft contact lenses did not show significant IOP changes under any condition (P >0.05). Eyes with a scleral lens also showed a small but significant thinning of peripapillary RNFL (pre-application: 110 ± 11 µm vs. post-application: 107 ± 11 µm, P < 0.001) after 8 hours of lens wear, which was not significant with soft contact lens wear (P > 0.05). IOP data obtained from Diaton showed poor within-participant variation and poor agreement compared to IOP data from the non-contact tonometer. Conclusion: This study suggests that short-term scleral lens wear may significantly raise IOP and cause transient peripapillary RNFL thinning, which returns to baseline immediately following lens removal. Monitoring IOP and RNFL is recommended for scleral lens wearers, with future research needed to assess the long-term effects.