Abstract
Abstract: :
Purpose: Optic disc haemorrhage is a well–known risk factor for glaucoma. We aimed to determine the frequency and associations of new episodes of optic disc haemorrhage detected in an older population–based cohort at 5– and 10–year follow–up examinations. Methods: Stereoscopic photographs of both optic discs were taken from 3654 baseline participants aged 49+ years in the Blue Mountains Eye Study. At the 5– and 10–year examinations, 2334 and 1953 participants (75.1% and 75.0%, respectively, of survivors at each interval). Among these, 2236 and 1624 persons, respectively, had gradable photographs at the 5–year and 10–year exams. Optic disc haemorrhages were identified from stereoscopic optic disc photographs (35 mm film) by trained graders and confirmed by an ophthalmologist (PM). Incident episodes were defined when an optic disc haemorrhage was detected at the 5– or 10–year exams in eyes without disc haemorrhage at baseline. Results: Among the 51 persons who had a disc haemorrhage at baseline, 5 of 22 (22.7%) who were re–examined at 5 years had further disc haemorrhages at different locations in the same eye; none of 14 who were re–examined at 10 years had further haemorrhages. After excluding the 5 persons who were found to have bilateral optic disc haemorrhages at baseline, 2233 persons at 5–year and 1622 persons at 10–year exams were considered at risk. The overall incidence of optic disc haemorrhage in either or both eyes was 1.16% (26 persons, 28 eyes) at the 5–year and 1.91% (32 persons, 35 eyes) at the 10–year exams. Incident episodes of optic disc haemorrhage were associated with increasing age (OR, 1.5 per decade; CI, 1.1–2.0) and vertical cup–disc (CD) ratio greater than 0.5 at baseline (OR, 2.6; CI, 1.5–4.5), after adjusting for age and vertical optic disc diameter. Interestingly disc haemorrhages were more frequent in left than right eyes (OR, 2.1; CI, 1.3–3.4). Potential risk factors including baseline hypertension, diabetes, BP or IOP were also assessed and no significant associations were found. Gender, regular use of aspirin and history of self–reported migraine history were also not related to incident disc haemorrhage. Relation to glaucoma will be discussed. Conclusions: Our data indicate a higher 5–year incidence of new disc haemorrhage episodes (1.2%) than reported from the Beaver Dam eye study (0.4%). Due to the transient nature of optic disc haemorrhages, our reported incident episodes from this population–based cohort study are likely to considerably underestimate the true incidence.