Optimisation of the methodology to identify, assess and grade lid wiper epitheliopathy

This thesis covers four clinical investigations into lid wiper epitheliopathy (LWE), a clinical sign associated with dry eye disease and contact lens discomfort. Due to previous inconsistencies in clinical approach to identifying LWE, the initial work used a semi-automated protocol to identify an optimal method for LWE assessment, in terms of volume of dye and post-dye viewing time. Double instillation of dye and clinical observation between 1-5 minutes for lissamine green and 3-5 minutes for sodium fluorescein is proposed. The next study evaluated the potential for false negatives if a non-optimal approach to identify LWE is used. The area of staining revealed using an optimal methodology was found to be significantly greater than that using a non-optimal methodology, which resulted in a 70% false negative rate for lissamine green and a 95% false negative rate for sodium fluorescein. The third investigation aimed to establish the time course of LWE in symptomatic habitual contact lens wearers after a day of daily disposable contact lens wear, the following day post-lens removal and 1-week after lens discontinuation. The sole intervention of temporarily discontinuing CL wear did not lead to LWE resolution, nor was there significant change after a day’s wear, suggesting a multifactorial aetiology of LWE. The final study’s goal was to develop, validate and explore acceptability of a new photographic scale, the Photographic Lid Wiper Epitheliopathy (PLWE) scale. To assess grading validity and grading reliability, observers graded the selected images using the PLWE and another commonly used grading protocol (Korb) on two separate sessions. The mean grade of all images was not statistically significant different between the PLWE scale and the Korb grading scale. Ninety five percent of the graders found PLWE easier to use than the Korb scale and the same percentage would consider using the PLWE scale in clinical practice.