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

Purpose: To investigate the short-term impact of scleral lens wear on intraocular pressure (IOP) and retinal nerve fiber layer (RNFL) thickness. We hypothesized that scleral lens wear would produce a measurable elevation in IOP accompanied by detectable RNFL thinning compared with soft contact lens wear. Methods: This prospective, randomized, contralateral-eye crossover study included 31 healthy participants (mean age: 26 ± 3 years). Each participant wore a 16.5 mm scleral lens over one eye and a soft contact lens over the fellow eye for 8 h, with assignments reversed between visits. IOP was measured using two tonometers: a transpalpebral Diaton tonometer and a non-contact tonometer (NCT), and RNFL thickness was measured by optical coherence tomography at four time points: pre- and post-lens application, and pre- and post-lens removal. Results: Eyes fitted with scleral lenses exhibited a significant IOP increase immediately after lens application (pre-application: 11 ± 3 mmHg vs. post-application: 16 ± 4 mmHg, p < 0.001), sustained throughout 8 h of wear (pre-removal: 16 ± 4 mmHg), and returned to baseline after removal (11 ± 3 mmHg). No significant IOP changes were observed in soft contact lens-wearing eyes (p > 0.05). Scleral lens wear was also associated with small but statistically significant peripapillary RNFL thinning (pre-application: 110 ± 11 µm vs. post-application: 107 ± 11 µm, p < 0.001), which returned to baseline after lens removal. No significant RNFL changes were observed with soft contact lens wear (p > 0.05). Bland–Altman analysis revealed poor agreement between Diaton and NCT measurements, consistent with the published literature on transpalpebral tonometry. Conclusions: Short-term scleral lens wear was associated with transient IOP elevation and peripapillary RNFL thinning, both reversible upon lens removal, in healthy young adults. These findings highlight the need for further longitudinal investigation in at-risk populations such as those with ocular hypertension, keratoconus, or early glaucoma before clinical monitoring recommendations can be established.