Central and peripheral regional variation of corneal nerve fibre parameters

Clinical relevance Regional variation in corneal nerve morphology may affect the interpretation of corneal confocal microscopy findings in clinical practice. Precise anatomical localisation is important when assessing corneal nerve health.Background Corneal confocal microscopy is increasingly used to quantify corneal nerve morphology in health and disease. However, regional differences in corneal nerve parameters across the cornea have not been fully characterised, and variation in imaging location may influence measured parameters.Methods Corneal nerves of 40 healthy volunteers were imaged in six regions using Heidelberg Retinal Tomograph III with the Rostock module (Heidelberg Engineering, Germany). Images were obtained from the central, inferior whorl, inferior, nasal, superior and temporal regions. Corneal nerve fibre length, branch density and fibre density were analysed using automated software developed at the University of Manchester, United Kingdom.Results The mean age of participants was 26.3 ± 3.7 years. Significant regional differences were observed in corneal nerve fibre length (p < 0.001), branch density (p < 0.001) and fibre density (p = 0.002). Fibre length in the inferior whorl was significantly higher than in the inferior (p = 0.002), nasal (p = 0.001) and temporal (p < 0.001) regions. Branch density was highest in the inferior whorl and exceeded all other regions (all p ≤ 0.001). Central fibre density was significantly higher than inferior fibre density (p = 0.02).Conclusion Significant regional variability exists in corneal nerve parameters. The central cornea exhibits the highest fibre density, whereas the inferior whorl demonstrates the greatest fibre length and branch density and serves as a distinct anatomical landmark. Subtle shifts in imaging location may produce markedly different measurements, highlighting the importance of standardised anatomical targeting.