Scleral lens peripheral modifications and regional variations in corneal oedema

To investigate the effect of peripheral scleral lens landing zone modifications upon short-term regional variations in corneal oedema.

Nine healthy participants wore different scleral lens designs ((1) spherical landing zone, (2) toric landing zone, (3) peripheral notches, and (4) peripheral channels) in a randomised order on four separate days for 100 min. Stromal oedema was quantified using high-resolution optical coherence tomography across the central, mid-peripheral, and peripheral cornea with the lens in situ. Eye Surface Profiler (ESP) images were also captured following the application of 10 μL of 2% sodium fluorescein, over a period of 100 min. Central and peripheral fluorescent intensity data were extracted from the ESP images and analysed using customised software to quantify tear exchange.

The channel lens design displayed less central oedema compared to the toric design (1.57 ± 0.45% less oedema, p = 0.04). In the corneal periphery, the magnitude of oedema was less for both the toric lens (2.66 ± 0.66% less oedema, p = 0.02) and the channel design (3.39 ± 0.97% less oedema, p = 0.04) in comparison to the spherical lens design. A highly significant correlation was observed between the magnitude of peripheral tear exchange after 90 min of lens wear and the magnitude of peripheral oedema (r = -0.61, p < 0.001).

Scleral lenses with either a toric landing zone or peripheral channels exhibited less peripheral corneal oedema than a spherical landing zone design, due to enhanced peripheral tear exchange.