Clinical, microbiological and biochemical characteristics of eyelids, and the effect of microblepharon exfoliation (MBE) on eyelid characteristics in contact lens discomfort were investigated. Upper lid-wiper epitheliopathy, lid parallel conjunctival folds, secretions quality, expressibility, foam at orifices and acini secretion reflectivity of meibomian glands, tear lipid layer thickness and tear evaporation were found to worsen with increased symptoms of discomfort, and an equation was developed to predict symptoms in lens wear. Symptomatic contact lens wearers had a significantly higher number of bacteria and greater proportions of heavy lipase producing bacteria compared to asymptomatic lens wearers. Improvements in clinical signs of the eyelids and a reduction in eyelid microbiota was observed 7-10 days after a single MBE treatment in symptomatic lens wearers. The clinical findings and the equation were validated on a different set of contact lens wearers. Improvements in meibomian gland secretion volume and quality, and tear evaporation with and without contact lenses in situ were sustained up to 25 days after exfoliation. Improvements in comfort scores and comfortable wear time were also sustained up to 25 days after MBE while end of day discomfort and average lens wear time showed improvement only until days 9 and 14. Symptomatic lens wearers harbour more number of Corynebacterium, Propionibacterium, coagulase-negative staphylococcus and Micrococcus species. Reductions in the number of coagulase-negative staphylococci and Micrococcus species were sustained up to 25 days after MBE in symptomatic lens wearers. Lipid analysis showed that meibum and tear lipidome significantly differed between symptomatic and asymptomatic lens wearers, both in terms of concentrations of essential lipids and their structural properties. Significant increases in phosphatidylcholine and sphingomyelin in both meibum and tear lipidome of symptomatic lens wearers sustained up to 25 days after MBE. Increases were also noted in the concentrations of lysophosphatidylcholine and lysophosphatidylethanolamine in tears of symptomatic lens wearers. This work concludes that eyelid physiology and microbiota may play a vital role in the development of ocular symptoms during contact lens wear. Changes caused by MBE use, may potentially alter tear bio-physical properties of the lipid layer in particular, leading to short-term improvements in the ocular comfort of symptomatic lens wearers.
|Date of Award
|12 Sept 2018
- University of New South Wales
|Mark Willcox (Supervisor), Ajay Kumar Vijay (Supervisor) & Jacqueline Tan (Supervisor)