Comfort and eye health in scleral shell wearers.

This study will investigate the effect of scleral shell prosthesis hydrophilicity (prosthesis material wettability) on prosthesis comfort of wear, required cleaning, lubrication use, dry eye symptoms, tear film features, prosthesis deposition, ocular microbiology, and ocular discharge in people who currently wear a scleral shell prosthesis. A minimum of 25 participants will be recruited. The study will require 3 visits: At visit 1, a full ocular and medical history will be taken and baseline assessments of ocular health will be made. Participants will have their scleral shell prosthesis of standard poly(methylmethacrylate) material professionally cleaned and polished and commence wearing their prosthesis for 4-6 weeks. During the 4-6 week wearing period, participants will record their frequency of prosthesis cleaning, lubrication, and wearing times on a form. Visit 1 will take no more than 1 hour. At visit 2, assessments of prosthesis comfort of wear, required cleaning, lubrication use, dry eye symptoms, tear film features, prosthesis deposition, ocular microbiology, and ocular discharge will be made. Their prosthesis will then be re-surfaced with a poly(methylmethacrylate) of increased hydrophilicity (increased wettability) and a further 4-6 weeks of prosthesis wear will be commenced. During the 4-6 week wearing period, participants will record their frequency of prosthesis cleaning, lubrication, and wearing times on a form. Visit 2 will take no more than 1 hour. At visit 3, assessments of prosthesis comfort of wear, required cleaning, lubrication use, dry eye symptoms, tear film features, prosthesis deposition, ocular microbiology, and ocular discharge will be repeated. Visit 3 will take no more than 1 hour. During the study participants wear their scleral shell prosthesis as they normally would, with no requirement to change the activities or behaviours. There will be no washout period. The standard poly(methylmethacrylate) material is the control and the poly(methylmethacrylate) of increased hydrophilicity is the intervention. The hydrophilicity of poly(methylmethacrylate) can be altered by adjusting the ratios of the usual constituents of poly(methylmethacrylate) during processing. No additional constituents or ingredients are used or added when the hydrophilicity is adjusted, and the standard lab processing procedures are carried out unchanged. A paper has been published on this: Pine, K. R., De Silva, K., Zhang, F., Yeoman, J., & Jacobs, R. (2021). Towards improving the biocompatibility of prosthetic eyes. Heliyon, 7(2), e06234. doi:https://doi.org/10.1016/j.heliyon.2021.e06234. All participants will obtain the standard poly(methylmethacrylate) material first, and the hydrophilic poly(methylmethacrylate) material, as unavoidable processing issues will occur if the shell is resurfaced more than once. Participants will not be informed which of the two veneer materials they obtain at their visits, or of possible differences in the materials. The ocular health assessments made during the study are commonly used ophthalmological and optometric practice, and will be carried out by an experienced research team of optometrists, ophthalmologists and ocularists (all clinicians have over 15 years experience in their respective fields). The study will be carried out at private and university eye clinics.