The Effect of Limbal Fenestrations on Scleral Lens-Induced Central Corneal Oedema

Persistent corneal oedema can lead to reduced visual performance and longer-term ocular complications in eyes with reduced endothelial cell function. The aim of this study was to quantify the effect of incorporating limbal scleral lens fenestrations on central corneal oedema.

Twenty young healthy adults (mean age ± standard deviation 32 ± 11 years) with normal corneas wore non-fenestrated and fenestrated (3 × 1 mm limbal fenestrations separated by 120°) OneFitMed+ scleral lenses in both eyes (on separate days) for 3 h. All other scleral lens parameters were held constant except for the addition of the fenestrations. Central fluid reservoir thickness and corneal oedema were quantified using optical coherence tomography, and corrections were made for small thickness variations between lens conditions.

The corrected central corneal oedema was significantly reduced following fenestrated lens wear (0.80 ± 0.93%) compared to non-fenestrated lens wear (1.32 ± 0.81%; a 39% relative reduction, p = 0.02). The reduction in central corneal oedema with the fenestrated lens was slightly greater for participants without an air bubble in the fluid reservoir (n = 10, 0.73 ± 0.80% less oedema, 45% relative reduction) compared to those with an air bubble (n = 10, 0.30 ± 1.05% less oedema, 30% relative reduction) but was not statistically significant (p = 0.31).

The incorporation of three 1 mm diameter limbal fenestrations separated by 120° reduced the magnitude of central corneal oedema by 39% on average in healthy eyes compared to a non-fenestrated scleral lens. A reduction in central corneal oedema was still observed without the presence of an air bubble within the fluid reservoir. Future studies investigating the long-term efficacy of different fenestration configurations in clinical populations are warranted.

This study was registered on the Australian New Zealand Clinical Trials Registry (Registration number 12622001164785p), date of registration 24 August, 2022.