Demodex Blepharitis: The Investigation of Practitioner Awareness and Perspectives, Microbiological Impact on Ocular Surface Inflammation, and Examination of Novel Tear Film Assessment Technologies
Authors:   , Sharma Nikhil 
Published: May 2024

Demodexmites have been implicated in causing chronic blepharitis. Demodexblepharitis does not have globally accepted diagnostic and management protocols, and the signs and symptoms of Demodex infestation overlap with other ocular surface diseases such as dry eye disease (DED) and meibomian gland dysfunction( MGD). Furthermore, Demodex blepharitis often remains an under diagnosed condition in clinical practice. Therefore, it was imperative to investigate why Demodex blepharitis is an underdiagnosed condition in clinical practice. An online survey was conducted among optometrists and ophthalmologists in India to evaluate knowledge, attitudes, and practices towards Demodex blepharitis. The study concluded that there was a lack of awareness and consensus among the surveyed practitioners with regards to diagnosis and appropriate treatment methods to control Demodex infestation (Chapter 2). A second survey was then conducted in Australia and New Zealand. This region was specifically chosen because Optometrists in Australasia have embedded therapeutic training in their curriculum. The study concluded that even highly skilled practitioners lacked consensus with regards to different methods used to confirm the presence of Demodex mites, the appropriate concentration of tea tree oil to eradicate the mites, and the duration of treatment (Chapter 3). The results from both studies were combined to compare how different eye care practitioners investigated and manage d Demodex blepharitis in disparate regions across the world. A secondary aim of the same study was to explore interprofessional differences in diagnostic and management practices i.e., to explore, what difference it makes with regards to regulating a profession in terms of the investigation, and management of a condition that does not have globally accepted diagnostic and treatment protocols. The result indicated that regulating the profession and upskilling practitioners to a therapeutic level as is standard in Australia and New Zealand, aids in more confident and evidence based clinical investigation (Chapter 4). A Delphi study was then conducted with 11 eye care professionals working in the United Kingdom. This study proposed diagnostic and management guidelines for the clinical detection of Demodex for use by eye care practitioners (Chapter 5). Demodex mites act as a carrier for the bacterium Bacillus oleronius. Antigenic proteins from this bacterium are capable of producing an inflammatory response. A series of in vitro experiments were conducted to investigate the effect of hyperosmolarity and bacillus proteins individually and when combined on conjunctival epithelial cells ( Chapter 6). The results suggested that the presence of bacterial proteins and hyperosmolarity have a dose and time dependent effect on cellular viability and toxicity. These experiments showed that patients affected with DED and Demodex blepharitis could experience more severe signs and symptoms. The Ocular surface analyser (OSA) is a novel piece of equipment for the measurement of tear film parameters The Diagnostic criteria of the OSA is not well characterized as are the techniques used to measure important tear characteristics. These techniques were investigated in Chapter 7 and the results showed the OSA can be successfully utilised in the diagnosis of DED.