UC Berkeley

Scleral lenses are an increasingly utilized contact lens modality for both visual rehabilitation and therapeutic management of ocular surface disease. Unlike conventional contact lenses, scleral lenses vault over the cornea and rest on the conjunctiva overlying the sclera, creating a post-lens fluid reservoir that protects the ocular surface, masks corneal irregularities, and alleviates dryness symptoms. Although widely prescribed for patients with corneal ectasia and ocular surface disease, scleral lenses are also increasingly used in otherwise healthy eyes to enhance comfort and visual performance. However, the same design characteristics that are responsible for these therapeutic and optical benefits also create a distinct ocular environment that may impact intraocular pressure (IOP), ocular surface health, post-lens tear dynamics, and patient tolerance. This research aimed to investigate the clinical impacts of scleral lens wear on IOP assessment, ocular surface responses, and patient-reported outcomes in both healthy and diseased eyes. Specifically, this dissertation evaluated (1) the relationship and repeatability of corneal and scleral pneumotonometry measurements during scleral lens wear, (2) the influence of prior contact lens wear experience on ocular surface responses and tolerance to scleral lens wear, (3) the clinical significance of post-lens tear film debris characteristics and their associations with patient-reported symptoms, and (4) the effects of post-lens fluid reservoir thickness on corneal thickness, tear dynamics, and IOP in patients with dry eye disease and corneal ectasia. Scleral pneumotonometry provided repeatable and clinically useful IOP measurements during scleral lens wear when corneal tonometry was not feasible. The relationship between corneal and scleral IOP measurements followed a piecewise linear pattern, emphasizing the importance of careful interpretation of scleral measurements at higher pressure levels and across ocular conditions. Short-term scleral lens wear was generally well tolerated in healthy and diseased populations, with minimal corneal swelling and favorable subjective ratings of comfort, visual quality, and dryness. However, for first-time scleral lens wearers, contact lens neophytes exhibited greater conjunctival and peripheral corneal epithelial responses than habitual soft contact lens wearers, suggesting that prior lens experience influences ocular surface adaptation to scleral lens wear. Post-lens tear film debris increased over 5 hours of wear in frequency, morphology, spatial extent, and severity, with diffuse debris severity and peripheral clustered debris extent associated with patient-reported fogging symptoms. In patients with corneal ectasia, thicker post-lens fluid reservoirs were associated with greater corneal swelling, although the magnitude remained minimal during short-term wear. Tear dynamics remained limited across cohorts and appeared to be driven primarily by lens settling and localized fluid redistribution rather than active tear exchange. Importantly, scleral lens wear did not produce clinically meaningful IOP elevations, including in diseased cohorts. In summary, scleral lenses create a distinct ocular environment that alters tear dynamics, ocular surface response, and clinical assessment of IOP while generally maintaining favorable short-term comfort and ocular surface integrity. This dissertation demonstrates that scleral pneumotonometry is a practical and repeatable method for monitoring IOP during scleral lens wear and identifies clinically meaningful debris characteristics associated with patient symptoms and post-lens tear dynamics. Collectively, these findings provide clinically relevant insight into the influence of ocular condition, prior lens experience, and fluid reservoir thickness on physiological responses during scleral lens wear. This work contributes evidence-based guidance for scleral lens fitting, patient monitoring, and long-term clinical management aimed at improving patient outcomes and supporting the safe and effective use of scleral lenses across diverse patient populations.