The Impact of a Scleral Lens on the Eye

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dc.contributor.advisorRedfern, Rachel
dc.contributor.committeeMemberBergmanson, Jan P.
dc.contributor.committeeMemberBurns, Alan R.
dc.contributor.committeeMemberMichaud, Langis
dc.creatorWalker, Maria K.
dc.creator.orcid0000-0001-8554-7678
dc.date.accessioned2021-09-01T18:47:25Z
dc.date.createdMay 2021
dc.date.issued2021-05
dc.date.submittedMay 2021
dc.date.updated2021-09-01T18:47:27Z
dc.description.abstractPurpose: There are several gaps in understanding ocular effects of a scleral lens (SL), particularly in the composition of the fluid reservoir (FR) that bathes the cornea and the impact of the landing zone radius (LZR) on the eye. The purpose of this dissertation is to (1) identify and compare molecules in the FR to basal tears, (2) determine the composition of the FR in midday fogging (MDF), and (3) determine if conjunctival compression from the LZR changes the intraocular pressure (IOP) and optic nerve head minimum rim width (MRW). Methods: (1) In normal subjects (n=15) wearing SL for 8-hour, basal and FR tear samples were collected, and immunomodulatory molecules were quantitated using Luminex multiplex immunoassay and compared between tear sample types. (2) In normal subjects (n=13) wearing SL, optical coherence tomography (OCT) was used to quantitate MDF, which was then correlated to relative lipid and protein abundances (mass spectrometry), SL parameters, and ocular surface health outcomes. (3) In normal subjects (n=26) wearing a SL on one (test) eye, MRW and IOP were measured using OCT imaging and iCare tonometry, respectively, at baseline, 2- and 6-hours SL wear and compared to the untreated (control) eye. Results: (1) Matrix metalloproteinase (MMP)-9 and MMP-10 were significantly greater in the FR, reaching 62.7 and 25.8 ng/ml, respectively, after 8-hours SL wear. (2) MDF samples were positively correlated to levels of wax esters (r = +0.76, P = 0.01) and hydrophobic lipids, negatively correlated to conjunctival compression (r = -0.59, P = 0.048), and not correlated to negative ocular surface health outcomes. (3) MRW thinning was not different in the test eyes after 6-hours of SL wear (-8 μm) vs control (-6 μm) eyes (P = 0.09). Mean IOP increased 2 mmHg post-SL removal (P = 0.02). Conclusions: In normal SL wearers, the FR is distinct from the basal tears and may retain inflammatory molecules. Hydrophobic lipids are primarily correlated to MDF, supporting the need for development of a lipophilic solution in the SL bowl to reduce the risk of MDF. Despite a modest increase in IOP post-SL removal, MRW is not significantly impacted during SL wear.
dc.description.departmentOptometry, College of
dc.format.digitalOriginborn digital
dc.format.mimetypeapplication/pdf
dc.identifier.citationPortions of this document appear in: Walker, Maria K., Carolina Lema, and Rachel Redfern. "Scleral lens wear: Measuring inflammation in the fluid reservoir." Contact Lens and Anterior Eye 43, no. 6 (2020): 577-584.; Walker, Maria K., Laura P. Pardon, Rachel Redfern, and Nimesh Patel. "IOP and optic nerve head morphology during scleral Lens Wear." Optometry and Vision Science 97, no. 9 (2020): 661-668.
dc.identifier.urihttps://hdl.handle.net/10657/8125
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectScleral lens
dc.subjectEye
dc.titleThe Impact of a Scleral Lens on the Eye
dc.type.dcmiText
dc.type.genreThesis
local.embargo.lift2023-05-01
local.embargo.terms2023-05-01
thesis.degree.collegeCollege of Optometry
thesis.degree.departmentOptometry, College of
thesis.degree.disciplinePhysiological Optics and Vision Science
thesis.degree.grantorUniversity of Houston
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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