- Ocular Surface Immune Regulation in Health and Disease
- Improved Measurement of Clinical Disease Activity and Damage
- The Role Of Femtosecond Lasers In Improving Outcomes in Anterior Segment Surgery
Ocular Surface Immune Regulation in Health and Disease
Geraint has explored the use of rapid, non-invasive ocular surface impression cytology (OSIC) combined with multi-colour flow cytometry to characterise conjunctival leukocytes. This has provided an insight in to immune regulation in health, ageing and ocular surface diseases (OSD). In healthy individuals, CD8αβ+ effector memory, cytotoxic, mucosal-homing T cells, capable of recognising herpetic viruses are the dominant population in the normal conjunctiva. This population is unaltered with age but other populations such as CD4+ T cells, capable of producing IFN-g do increase, indicating a potential role in healthy ageing.
During his PhD, Geraint studied a blinding condition called Ocular Mucous Membrane Pemphigoid (OcMMP), an autoimmune immunobullous disease resulting in conjunctival inflammation and corneal scarring. A major challenge in OcMMP is the observation that scarring may take place without typical signs of inflammation, namely conjunctivitis. By using OSIC in a cohort of patients with OcMMP, an elevation in inflammatory neutrophils were observed and this was associated with progression of scarring, even in the clinically non-inflamed eye. It is hoped that this can be translated in to more effective therapeutic intervention by exploring neutrophils as a biomarker of sub-clinical inflammation and their role in the scarring process.
Following his PhD, Geraint has worked on determining a better understanding of immune regulation of the ocular surface infections including T cell recognition and regulation of Herpes Simplex Keratitis (HSK). HSK is an important disease as the Herpes Simplex Viruses (HSV) are responsible for ocular disease including recurrent HSK or inflammation of the cornea. This results in blinding complications including diminished corneal sensation, corneal scarring, the formation of abnormal corneal blood vessels and secondary bacterial infection. He is optimising ex vivo quantification of peripheral T cell HSV epitope recognition and memory status and determining whether they differ in those with and without HSK, in the hope of targeting therapy more effectively.
Improved Measurement of Clinical Disease Activity and Damage
Alongside his laboratory work in to the immune regulation of the ocular surface, Geraint has an active interest in improving the clinical phenotyping of human ocular disease. He has previously developed and validated a tool to measure the scarring process in cicatrising conjunctivitis such as OcMMP. This tool has been employed to undertake an anthropological study in to the normal anatomy of the conjunctival fornices in Caucasians.
Geraint has helped establish a steering committee of ocular surface experts from around the UK in order to define activity and damage indices in disease. This has employed a Delphi process among anterior segment and corneal specialists to determine clinical parameters of OSD clinical scoring systems by establishing clear distinctions between activity and damage indices, and validating rankings of disease scales in order to standardise clinical scoring systems for use in clinical trials.
Geraint is working to improve detection and classification of ocular surface infections such as HSK through imaging platforms, including the role of in vivo confocal microscopy to determine corneal changes including nerve plexus density in HSK as an adjunct to improving monitoring of disease activity and damage.
The Role Of Femtosecond Lasers In Improving Outcomes In Corneal and Cataract Surgery
Geraint has secured travelling fellowships from the Royal College of Ophthalmologists and the Eleanor Peel foundation to study the application of femtosecond laser platforms in corneal and cataract surgery at SERI and SNEC. He is currently working with low energy, high repetition femtosecond laser systems to determine the effects of liquid optic interfaces on intra-ocular pressure, wound construction, capsulotomy and fragmentation and corneal opacification in cataract surgery. Furthermore he is determining the efficacy and safety profile of small incision lenticule extraction (SMILE) and LASIK combined with collagen cross-linking in animal models.