Abstract:
To assess optic nerve head topographic parameters using the Heidelberg retinal tomograph (II) in a normal elderly population.
Optic nerve head analysis of 918 eyes of 459 normal elderly patients was performed using the Heidelberg retinal tomograph (HRTII). All patients were consecutive in a cohort screened for eye disease. Normals were defined with a normal visual field on automated suprathreshold screening, intraocular pressure less than 22mmHg, and minimum corrected visual acuity of 6/12. All optic discs were contoured by two investigators and the mean parameters analysed. The effects of age, sex, and disc size were assessed. Statistical analyses were performed using Mann–Whitney U test and Spearman’s rank correlation.
Subjects’ mean age (262 female and 197 male) was 72.6 years (SD 5.1, range 65.5–89.3). Mean (SD) global disc area, cup–to–disc area ratio, and neuroretinal rim area were 1.98 (0.36), 0.22 (0.14), and 1.52 (0.31) respectively. Disc area did not differ significantly based on eye side or sex. Females were found to have significantly smaller cup areas/volumes and cup–to–disc area ratios than males, and a larger rim volume, mean retinal nerve fibre layer (RNFL) thickness and cross sectional area. Most HRT parameters were found to be significantly influenced by disc size.
This is the first large study of HRT II parameters in the elderly normal population. This age range is more relevant to glaucoma and our normal range data more pertinent to discriminant analyses separating normals from glaucoma in screening for the disease. Given the systematic differences between males and females parameter normal ranges should be quoted for each sex.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • optic disc • imaging/image analysis: clinical