Bruch Membrane Opening Minimum Rim Width Changes During Scleral Lens Wear

The purpose of this study was to evaluate the change in Bruch membrane opening minimum rim width (BMO-MRW) during scleral lens (SL) wear.

Twenty young white subjects were enrolled (10 women and 10 men); preliminary evaluation consisted of serial measurements of intraocular pressure (IOP) using a dynamic noncontact tonometer (Corvis, Oculus), which also yielded a corneal biomechanical index and central corneal thickness, and BMO-MRW using optical coherence tomography imaging (OCT) imaging (Spectralis, Heidelberg) through 6 hrs to establish normative diurnal curves. The next day, participants were fitted with a 16-mm SL on one eye, and OCT measurements were repeated over the same time span. Statistical analysis was carried out with a two-way analysis of variance. Multiple linear regressions were used to identify significant associations.

The average diurnal variation for BMO-MRW without lenses was -4.65 μm (95% confidence interval [CI], 0.52-8.77) after 6 hours, whereas it decreased by 8 μm (95% CI, 3.87-12.12; P<0.001) after 6 hours of SL wear. The difference between variations after 6 hours was then -3.35 μm (P=0.029). Variation of the BMO-MRW did not significantly correlate with corneal rigidity (CR), central corneal thickness (CCT), and refractive error (r=-0.224, -0.054 and -0.085, respectively).

Scleral lens wear induces a statistically significant decrease in BMO-MRW that could potentially be attributed to a change in IOP. The change in BMO-MRW was not affected by CR, CCT, or refractive error. Further studies are needed to better understand the significance of the observed changes at the optic nerve head during scleral lens wear.