EVect of aging on optic nerve appearance: a longitudinal study

Aim—To determine whether aging causes detectable changes in the appearance of the optic disc. Methods—A retrospective longitudinal study was performed with quantitative and qualitative evaluations of digitised stereoscopic optic disc photographs of 224 eyes of 224 subjects. There were three groups: 100 normal subjects from the Framingham Eye Study, 68 glaucomatous patients followed longitudinally, and 56 normal subjects and glaucoma patients who had separate sets of disc photos taken on the same day. A disc was considered qualitatively worse if two of three experienced observers agreed that it was worse. Quantitative progression was defined as a >10% decrease in rim/disc area ratio measured with computer assisted planimetry. Results—With quantitative evaluation, normal eyes (mean follow up 13 years) and same day eyes displayed no statistically significant diVerence in change of rim/ disc area ratios (p=0.095), nor in the number of discs that progressed—five of 100 (5%) v two of 56 (4%) respectively. Glaucomatous eyes (mean follow up 9 years) showed a quantitative loss of disc rim in 24 of 68 (35%), and diVered significantly from the normal eyes both in the change of rim/disc area ratio (p<0.0005) and number of discs that progressed (p<0.0005). With qualitative evaluation, the number of progressive discs in the glaucomatous eyes (31%) diVered significantly (p<0.0005) from the normal eyes (3%) and the same day eyes (0%). Conclusions—Over a period of follow up appropriate for long term outcome studies in glaucoma, there was no quantitatively or qualitatively detectable neuroretinal rim loss in normal aging optic nerves with stereoscopic optic disc photographs. (Br J Ophthalmol 1999;83:567–572) Ophthalmologists monitor the appearance of the optic nerve head to obtain crucial information regarding the progression of a patient’s glaucoma and the eVectiveness of therapy. It is often possible to appreciate changes in the optic nerve disc appearance before any visual field loss can be perceived by the patient or detected with visual field testing. 8 Changes in optic disc appearance are caused by the death of retinal ganglion cells and the loss of their axons in the optic nerve; however, the exact mechanisms of damage remain unknown. The eVect of aging on the appearance of the optic disc is not known with certainty. Aging is generally believed to have little eVect on disc rim area; however, most studies that have addressed this question have either been cross sectional or have had small numbers of subjects in longitudinal studies of relatively short duration. It is important to know whether aging alone can cause clinically detectable changes in optic disc appearance that may be mistaken for early glaucomatous progression over a long enough time period suitable for clinical glaucoma trials. The purpose of this study was to determine whether aging causes detectable changes in the appearance of the optic disc.