The Role of Hand-held Optical Coherence Tomography in Paediatric Glaucoma

Purpose: Table-mounted optical coherence tomography (OCT) instruments have revolutionised diagnosis and management in adult glaucoma, although children particularly those ≤ 5 years of age have been deprived of this technology due to poor cooperation. The hand-held OCT (HH-OCT) device is child-friendly and has potential to improve paediatric management. This thesis demonstrates the feasibility of HH-OCT for imaging the cpRNFL and optic nerve head (ONH) in paediatric glaucoma, and also assesses the reliability and diagnostic ability of 3-dimensional analysis.

Methodology: HH-OCT imaging was performed on 103 children and feasibility was assessed. Initial 2-dimensional analysis of cpRNFL and ONH confirmed good diagnostic ability of glaucoma. Reliability of optimal 3-dimensional analysis of cpRNFL was tested on a small sample, and justified analysis of all paediatric patients. Exploratory factor analysis (EFA) was performed to identify the most sensitive parameters for simplified detection of paediatric glaucoma.

Results: Feasibility assessment of images suitable for 3-dimensional analysis, in children of mean age 6.98±4.42 years (42/103 children were ≤5 years), resulted in 75% to 88% success in individual cpRNFL quadrants, and 67% for full cpRNFL. Excellent reliability of cpRNFL quadrants at a 6° visual angle was achieved, with high ICCs of ≥0.88. 2-dimensional and 3-dimensional analysis found significant thinning of cpRNFL quadrants, drastically larger cups and smaller rims. EFA revealed two main clusters of parameters in 3-dimensional analysis: (i) cpRNFL and rim parameters and (ii) cup and cup:disc ratio parameters. A combination of two representative parameters from each cluster resulted in AUC values of >0.918, similar to AUCs using the two principal factors.

Conclusion: We demonstrate successful HH-OCT imaging and 3-dimensional analysis of paediatric glaucoma in young children, for the first time. Combining OCT parameters derived from the ONH region into a simple model has important diagnostic potential for detection and monitoring of disease progression in childhood glaucoma.