Morphology of the optic nerve head and factors affecting it in the Northern Finland birth cohort

The study aimed to examine the topographical features of the optic nerve head (ONH) and retinal nerve fibre layer (RNFL) and evaluate the effect of ocular and physiological factors on them in a middle-aged population. A random sample of 1552 individuals from Northern Finland aged 45-49 was analyzed using laser scanning tomography and optical coherence tomography. The RNFL measurements included global thickness and six zones of automated structure-function analysis. The influence of various factors such as central corneal thickness, refractive correction, intraocular pressure, anterior chamber angle, gender, blood pressure, height, weight, and body mass index on the tomographic data was analyzed. The results showed that the optic disc area had a strong correlation with all other parameters of ONH morphology and spherical equivalent. The correlations between ONH and RNFL measurements were weaker. Gender, central corneal thickness, anterior chamber angle, blood pressure, height, and body mass index had statistically significant yet weak correlations with some ONH parameters. Other than spherical equivalent, the studied anatomical and physiological attributes had limited predictive value on the ONH morphology. The optic disc area had a significant effect on other measurements of ONH tomography and should be considered in determining the normal thresholds for ONH morphology.