Inner retinal thickness refers to the combined thickness of retinal layers from the nerve fibre layer through to the inner nuclear or inner plexiform layers, depending on the definition used. It is an important metric in diseases affecting ganglion cells and their connections.
Measurement
OCT devices segment macular or peripapillary scans to calculate thickness of these inner layers, often reported as ganglion cell complex or inner retinal maps. Values are compared with normative databases and tracked over time.
- Non-invasive and repeatable when scans are well centred and of good quality
- Sectoral and average measures can be generated
- Thinning indicates loss of inner retinal neurons or axons
- Coexisting macular disease may influence local measurements
Clinical Significance
Inner retinal thickness is particularly relevant in glaucoma, optic neuropathies, and some neurological diseases. Reductions correlate with visual field loss and can precede overt clinical signs.
- Supports early detection and monitoring of neurodegenerative change
- Used alongside retinal nerve fibre layer and ganglion cell analyses
- Serial measurements inform decisions about treatment effectiveness
- Interpretation requires attention to segmentation accuracy and coexisting pathologies
