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Abstract #15708 Published in IGR 2-3
Use of sequential Heidelberg retina tomograph images to identify changes at the optic disc in ocular hypertensive patients at risk of developing glaucoma
Kamal DS; Garway-Heath DF; Hitchings RA; Fitzke FWBritish Journal of Ophthalmology 2000; 84: 993-998
AIM: To determine if global and segmental changes in optic disc parameters of sequential Heidelberg retinal tomograph (HRT) images develop in individual ocular hypertensive (OHT) patients without white-on-white visual field defects. METHODS: Patients and normal controls were recruited from a prospective OHT treatment trial. The subject groups consisted of 21 OHT patients who had converted to early glaucoma on the basis of visual field criteria (24-2 program on the Humphrey perimeter), 164 OHT subjects with normal visual fields, and 21 normal controls. Sequential HRT images 16-21 months apart were obtained for each subject, and segmental optic disc parameters were measured to determine if any change had occurred. From the analysis of sequential HRT images of the 21 normal eyes, the authors established normal limits of interimage variation. Individual discs in each group showing changes above the 95% limit of normal variability were then sought. RESULTS: Several segmental and global optic disc parameters were found to show significant change in the converter group before confirmed visual field change, confirming the authors' previously published results. Individual optic disc analysis using the 95% limit of normal variability data demonstrated glaucomatous change in 13 of 21 converter eyes. Forty-seven of the 164 OHT eyes with normal visual fields showed changes in global and segmental parameters in a 'glaucomatous' direction above the level expected for normal variability. The parameters that changed most frequently in the OHT eyes were: global cup volume (6.7% of discs), inferonasal cup volume (11%), inferotemporal cup volume (8.5%), and superotemporal cup area (7.3%). CONCLUSIONS: The authors identified change in a subset of ocular hypertensive patients which could predate the development of glaucomatous visual field loss. The HRT could be of value in the sequential follow-up of those suspected of having glaucoma, by identifying eyes at risk of developing glaucoma. However, further refinement of the technique is required to eliminate some of the inherent variability of the analysis method described, and to increase the ability to detect at risk individuals.
Dr. R.A. Hitchings, Glaucoma Unit, Moorfields Eye Hospital, London EC1V 2PD, UK
Classification:
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
6.9.1 Laser scanning (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis)
