Ong, Gek L, Ripley, Lionel G, Newsom, Richard S, Cooper, Matthew and Casswell, Anthony G (2004) Screening for Sight-threatening Retinopathy: Comparison of Fundus Photography with Automated Color Contrast Threshold Test. American Journal of Ophthalmology, 137 (3). pp. 445-452. ISSN 0002-9394

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Abstract

Purpose: To compare tritan contrast threshold (TCT) with fundus photography in screening for sight-threatening diabetic retinopathy (STDR), before significant visual loss. Design: Prospective, comparative study. Methods: A total of 510 consenting diabetic patients attending a hospital-based photographic screening clinic were recruited over a 2-year period. Exclusion criteria included visual acuity of worse than 6/9, previous photocoagulation, and a history of previous eye disease known to affect color vision. The automated TCT test was performed using a computerized cathode ray tube-based technique. Retinal photography was performed using a Polaroid mydriatic fundus camera with a 45 degrees field. Grading of diabetic retinopathy was carried out by an ophthalmologist using slit-lamp biomicroscopy and a 78-diopters lens. Assessments of sensitivity, specificity, and predictive values for both fundus photography and the TCT test were made. Results: Both the fundus photography and TCT test correlated significantly with the presence of STDR (P < .0001, 2 test). The TCT test yielded a sensitivity of 94% (95% confidence interval [CI], 73%¿ 100%) and a specificity of 95% (95% CI, 92%¿ 96%) for detection of STDR compared with a sensitivity of 88% (95% CI, 66%-97%) and a specificity of 95% (95% CI, 93%¿97%) with fundus photography. Combined modality improved overall screening performance. Conclusion: The TCT assessment is an effective and clinically viable technique, in comparison with fundus photography, to screen for STDR among a diabetic population. Additionally, our results also showed that combining the TCT test with fundus photography greatly increases the performance of screening for STDR.

Item Type:	Article
Additional Information:	Colour-vision deficit is identified as a better basis for screening for sight-threatening diabetic retinopathy than the currently preferred fundus photography which is improving with the advent of modern digital cameras but these and the SGM/SCS are relatively expensive, static apparatus and this has led to the development of the Trafford Anomaloscope (red/green) and the Sussex Anomaloscope (tritan) which are cheap, portable, desk-top instruments for colour-vision assessment. Clinical trials are proving successful and have led to industrial sponsorship from Peca Electronics (WorldWideWeb.anomaloscope.co.uk) and to the adoption of these new machines for a retinopathy screening programme in the Australian outback. (Patent GB2411010).
Schools and Departments:	School of Engineering and Informatics > Engineering and Design
Depositing User:	Lionel Ripley
Date Deposited:	06 Feb 2012 19:24
Last Modified:	30 Mar 2012 08:47
URI:	http://sro.sussex.ac.uk/id/eprint/20456

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