Tear film changes and predictive factors of symptomatic dry eyes and visual light sensitivity after laser refractive surgery

Abstract

This thesis aimed to evaluate the changes in the tear film and MG morphology among subjects with pre-clinical dry eye and compare them with normals defined by their OSDI scores. Furthermore, the tear film changes after laser refractive surgery among symptomatic dry eyes were evaluated along with the predictive factors for the occurrence of transient and persistent symptomatic dry eyes. Also, changes in the visual light sensitivity after laser refractive surgery were assessed using an automated Ocular Photosensitivity Analyser (OPA). newlineIn this thesis, a prospective study was conducted at the University of Hyderabad on normal subjects presenting for a regular eye examination. Tear film such as non-invasive break-up time (NIBUT), tear meniscus height (TMH), Schirmer s test and corneal staining and MG morphology (MG length, MG width, MG loss and tortuosity) were assessed and the subjects were categorised into two groups based on an OSDI threshold score of and#61619;13. Among subjects presenting for laser refractive surgery, OSDI scores and other tear film tests such as NIBUT, TMH and Schirmer s test were performed preoperatively on the day of surgery and postoperatively at 1 week. Subjects were categorised into three dry eye groups based on the OSDI threshold score of and#61619;13 at the pre and postoperative visit as, no dry eye, transient symptomatic dry eye and persistent symptomatic dry eye. For assessing visual light sensitivity, visual photosensitivity thresholds (VPT) were assessed preoperatively on the day of surgery and postoperatively at 1 week and 1 month. newlineIt was found that NIBUT was lower and the MG length of the lower lid was lesser among subjects with pre-clinical dry eye when compared to normals. Other tear film tests and MG morphology did not vary significantly between the groups. Among laser refractive newlineABSTRACT newline Tear Film changes and Predictive factors of Symptomatic Dry Eyes and newlineVisual Light Sensitivity after Laser Refractive Surgery newlinexiii newlinesurgery subjects, it was found that 24% of them had symptomatic dry eyes before