Objectives: Fluid reservoir (FR) depth is an important parameter in the evaluation of scleral lens fitting, yet the range of depths compatible with successful wear, clinicians' ability to estimate depth, and implications of FR depth on midday fogging have yet to be fully elucidated. This study quantified FR depth of habitual scleral lens wearers, compared clinician estimates and image-based measurements of depth, and evaluated optical density of the FR to assess the effect of FR depth on midday fogging. Methods: Habitual scleral lens wearers consented to participate at three sites. FR depth was estimated using slitlamp evaluation by experienced examiners. Measurements of the depth and optical density of the FR were collected using Scheimpflug images. Results: The mean estimated (265±97; range: 0–500 µm) and image-derived (264±111; range: 40–555 µm) FR depths were not statistically different ( P =0.9). No correlation was found between optical density and depth of the FR. Conclusion: Successful scleral lens wear can occur with a wide range of FR depths. Experienced practitioners can accurately estimate FR depth using slitlamp examination. Midday fogging due to debris behind a scleral lens was not related to FR depth in this group of habitual wearers.
Fogt et al. (2026) studied this question.