Early optic disc changes in open-angle glaucoma

INTRODUCTION: Early diagnosis of chronic open-angle glaucoma is difficult: early changes in the optic disc often precede troubles in the field of vision, which occur gradually with no typical initial aspect. We report here the results of optic disc observations in normal subjects who became glaucomatous. OBSERVATIONS AND METHODS: A study was conducted on 64 eyes of 51 subjects followed on average over 12 years. At the start these eyes were normal or at risk for glaucoma for various reasons. Doubtful, difficult cases (severe myopia, dysversion or with associated pathology) were eliminated. Eventually, all the eyes presented open-angle glaucoma. All patients underwent clinical and paraclinical examinations by the same examiner. The optic discs of 78 dilated eyes were examined with a slit lamp and a 78-dioptre lens and the results systematically tabulated. Of the 78 optic discs, 40% had initial morphological characteristics (including cup/disc ratios) that were difficult to identify precisely. Preference was given to certain criteria that were easy to evaluate and likely to change. RESULTS: The classic aspects of glaucomatous papillary excavation appearance were observed. Forty-four discs showed notable changes (19 typical changes, 25 atypical), which were observed before visual field abnormalities. The size of the disc influences how the disease develops. Also noted were the frequency of changes in the slope of the papillary profile curve (third moment) and the frequency of changes in the quality of the papillary tissue, which takes on a translucent character locally. CONCLUSION: Documented and comparative observation of the optic disc remains a good and simple means for supervising subjects at risk for and in early diagnosis of chronic open-angle glaucoma. The evaluation of changes in the optic disc is greatly aided by the collection and the systematic recording of observations.