Abstract
PURPOSE: Trials exploring novel treatments for inherited retinal diseases (IRDs) have utilised microstructural retinal changes for outcome measures, but such changes in children are incompletely described. We aimed to characterise the retinal microstructural in children with IRDs versus controls using optical coherence tomography (OCT). METHODS: Cross-sectional study of retrospective OCT data from 51 children (91 eyes) with IRDs attending the Melbourne Children's Eye Clinic and 64 controls (126 eyes) recruited prospectively at Australian College of Optometry clinics. OCT was performed using a Nidek RS-3000 with volume scans in each participant eye. Image quality was manually reviewed. Semi-automated layer segmentation was performed and thickness based on eccentricity relative to the central fovea position was calculated to standardise measurements between participants. RESULTS: Inner retinal layer thickness was significantly increased in IRD groups versus controls (rod-cone p < 0.0001; cone-rod p < 0.0001; macula p < 0.0001; cone p < 0.0001). This was not observed for photoreceptor complex thickness where instead thinning versus controls was seen in cone-rod disorders (rod-cone p = 0.89; cone-rod p < 0.0001; macula p = 0.21; cone p = 0.17). Total thickness was significantly reduced in cone and cone-rod group versus controls, but not in other IRD types (rod-cone p = 0.25; cone-rod p < 0.0001; macula p = 0.74; cones p = 0.004). CONCLUSION: Our findings suggest retinal remodelling takes place in childhood-onset IRDs. Clinical trials in IRDs should consider remodelling when evaluating treatment effects. Future studies on the longitudinal natural history of retinal microstructural changes in childhood IRDs are required to address the impact of factors including IRD type, sex, age and disease duration.