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Abstract #5226 Published in IGR 1-2
Cup-to-disc ratio: ophthalmoscopy versus automated measurement in a general population: The Rotterdam Study
Wolfs RC; Ramrattan RS; Hofman A; De Jong PTOphthalmology 1999; 106: 1597-1601
OBJECTIVE: To determine the correlations between ophthalmoscopic estimations and the measurements with a semiautomated image-analysis device of the vertical cup-to-disc ratio (VCDR) in the human optic disc. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: All subjects 55 years of age and older from the population-based sample of 6777 ophthalmologically examined subjects from the Rotterdam Study of whom gradable optic disc transparencies of at least 1 eye and ophthalmoscopic data of the same eye were available. Main outcome measures: Ophthalmoscopic assessment of the VCDR and semiautomated measurement of the VCDR. METHODS: Indirect and direct ophthalmoscopy were performed in mydriasis to assess the VCDR. Optic disc transparencies made with a simultaneous stereoscopic telecentric fundus camera were analyzed with a semiautomated measurement system (Topcon Imagenet). RESULTS: In 5143 subjects, the mean ophthalmoscopic VCDR was 0.30 (standard error (SE), 0.0021; range, 0.00, 1.00) compared with a semiautomatically measured VCDR of 0.49 (SE, 0.0019; range, 0.04, 0.86; difference, 0.19; p<0.0001). The overall correlation between both methods was moderate (correlation coefficient, 0.61; SE, 0.11) and lower in small optic discs. Semiautomated optic disc measurements correctly identified 76% of the glaucoma cases (as defined using visual field data and ophthalmoscopic data about the optic disc). CONCLUSION: Semiautomated measurements of the VCDR are larger than the ophthalmoscopic VCDR estimate with a moderate correlation. The interobserver variability using Imagenet was smaller compared with the ophthalmoscopic assessments, and Imagenet was better standardized, which is important for epidemiologic surveys and follow-up studies.
R.C. Wolfs, Department of Ophthalmology, Erasmus University, Rotterdam; the Netherlands
Classification:
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
6.9.5 Other (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis)
