Visual acuity measurement and ocular co-morbidity in diabetic retinopathy screening

• Published in: British journal of ophthalmology Vol. 92; no. 6; pp. 775 - 778
• Main Authors: Scanlon, P H, Foy, C, Chen, F K
• Format: Journal Article
• Language: English
• Published: BMA House, Tavistock Square, London, WC1H 9JR BMJ Publishing Group Ltd 01.06.2008; BMJ; BMJ Publishing Group LTD
• Subjects: Adolescent; Adult; Age; Aged; Aged, 80 and over; Amblyopia - complications; Amblyopia - physiopathology; Biological and medical sciences; Blindness - etiology; Cataract - complications; Cataract - physiopathology; Diabetes; Diabetes Mellitus - physiopathology; Diabetes. Impaired glucose tolerance; Diabetic retinopathy; Diabetic Retinopathy - complications; Diabetic Retinopathy - diagnosis; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; Humans; Insulin; Macular degeneration; Macular Degeneration - complications; Macular Degeneration - physiopathology; Male; Mass Screening - methods; Medical sciences; Middle Aged; Miscellaneous; Morbidity; Ophthalmology; Patients; Retinopathies; Sensitivity and Specificity; Vision, Low - etiology; Visual Acuity; Visual impairment; United Kingdom > UK; Endocrinopathy; Measurement; Eye; Eye disease; Retinopathy; Ocular; Diabetes mellitus; Visual acuity; Ophthalmology; Medical screening; Epidemiology; Morbidity
• ISSN: 0007-1161; 1468-2079
• DOI: 10.1136/bjo.2007.128561

Aims:To evaluate the relationship between best corrected visual acuity (BCVA), age, type of diabetes, sight-threatening diabetic retinopathy (STDR) and ocular co-morbidity.Methods:1549 randomly selected people with diabetes mellitus (DM) from a countywide digital photographic screening programme had standardised logarithm of minimum angle of resolution (logMAR) BCVA measurement, followed by slit-lamp biomicroscopy examination by an experienced ophthalmologist.Results:Subnormal vision (logMAR ⩾0.3, Snellen ⩽6/12) and blindness (logMAR >1.3, Snellen <3/60) in the better-seeing eye were found in 9.0% and 0.45%. The sensitivity, specificity and positive and negative predictive values of using subnormal vision to screen for STDR in an individual eye were 33.4%, 85.9%, 18.6% and 93.0%, respectively. Important contributory causes of moderate visual loss (logMAR 0.50 to 0.98, Snellen 6/18 or worse but better than 6/60) and of Acuity Blindness (logMAR ⩾1.0, Snellen 6/60 or worse) in an individual eye were lenticular opacity (including capsular opacification) 49%, macular degeneration (including myopic degeneration) 29%, diabetic maculopathy 15%, other media causes (including corneal opacity) 13% and amblyopia 10%.Conclusion:The majority of visual loss in a population with diabetes is due to causes other than diabetic retinopathy. BCVA alone is not a reliable criterion in predicting STDR.