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Abstract #23787 Published in IGR 11-2
Quantitative assessment of optic nerve head morphology and retinal nerve fibre layer in non-arteritic anterior ischaemic optic neuropathy with optical coherence tomography and confocal scanning laser ophthalmoloscopy
Chan CK; Cheng AC; Leung CK; Cheung CY; Yung AY; Gong B; Lam DSBritish Journal of Ophthalmology 2009; 93: 731-735
BACKGROUND/AIMS: To compare the optic disc parameters between patients with non-arteritic anterior ischaemic optic neuropathy (NAION) and normal controls, using optical coherence tomography (OCT) and Heidelberg Retinal Tomograph III (HRT), and to evaluate the structure-function relationship in NAION eyes. METHODS: Both eyes of 22 patients with typical unilateral NAION of ≥6 months' duration and 52 eyes from 52 randomly selected normal subjects underwent Humphrey visual field (HVF) examination and measurement of optic disc and retinal nerve fibre layer thickness (RNFLT). RESULTS: For the NAION-affected eyes, NAION fellow eyes and normal controls, the ocular magnification-corrected OCT disc areas were respectively 1.849 (SD 0.343) 2, 1.809 (0.285) 2 and 1.964 (0.386) 2; the cup areas were 0.246 (0.187) 2, 0.172 (0.180) 2 and 0.469 (0.332) 2. On HRT, the disc areas were 2.11 (0.38) 2, 2.06 (0.40) 2 and 2.16 (0.42) 2; and the cup areas were 0.28 (0.34) 2, 0.25 (0.18) 2 and 0.48 (0.32) 2. On both OCT and HRT, the cup areas and cup-disc area ratios (CDAR) of both eyes of NAION patients were significantly smaller than controls (p≤0.01), but the disc areas were not (p≥0.21). There was a significant correlation between HVF mean deviation and OCT RNFLT (r = 0.44, p = 0.04) but not with HRT RNFLT (p = 0.30) in NAION-affected eyes. CONCLUSION: NAION patients have smaller optic cups and CDARs in both eyes compared with controls. A larger sample size is necessary to demonstrate if disc size affects the risk of developing NAION. The NAION-affected eyes' OCT RNFLT correlated with HVF mean deviation but the HRT RNFLT did not.
Department of Ophthalmology & Visual Sciences, Chinese University of Hong Kong, Hong Kong. kmcc2001@hotmail.com
Classification:
10 Differential diagnosis e.g. anterior and posterior ischemic optic neuropathy
6.9.1.1 Confocal Scanning Laser Ophthalmoscopy (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.1 Laser scanning)
6.9.2.2 Posterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
