Impact of a three-month period of mini-scleral lens usage on intraocular pressure and the anterior chamber angle in patients with keratoconus

To investigate the long-term effects of mini-scleral lens wear on intraocular pressure (IOP) and anterior chamber angle (ACA) in patients with keratoconus (KCN).

A convenience sampling method was adopted to enroll KCN patients between November 2023 and April 2024. All participants had a definitive KCN diagnosis and were eligible for mini-scleral lens fitting. Baseline optometric examinations included visual acuity measurement, objective and subjective refraction, and slit-lamp biomicroscopy. Mini-scleral lenses were fitted with trial lenses. Participants returned for a 3-month follow-up, where all examinations were repeated.

Seventeen KCN patients (12 males) were enrolled, aged 20–53y with a mean age of 38.09±12.86y. Mean IOP rose by 0.33±1.60 mm Hg after mini-scleral lens wear, without statistical significance (P=0.525). The nasal ACA increased by 0.73°±2.69° (P=0.390), whereas the temporal ACA decreased by −1.46°±3.10° (P=0.152). In severe KCN cases, mean IOP elevated from 7.60±0.96 to 8.60±1.14 mm Hg after lens fitting. By contrast, mild-to-moderate KCN patients showed a slight IOP decline from 11.58±2.50 mm Hg at baseline to 11.33±2.42 mm Hg post-fitting. Females presented a statistically significant reduction in temporal ACA after lens wear (P=0.020). Older baseline age was negatively correlated with temporal ACA width (β=−0.719, P=0.041).

Patients with advanced KCN face higher risks of IOP elevation after mini-scleral lens fitting. ACA changes induced by mini-scleral lenses vary by sector, with temporal angle narrowing being more prominent. Clinicians should closely monitor potential temporal angle narrowing, especially in female and older KCN patients during mini-scleral lens fitting.