Victorian orthoptists' performance in the photo evaluation of diabetic retinopathy
ABSTRACT Purpose: The aim of this study was to investigate the effectiveness of orthoptists in detecting various grades of diabetic retinopathy (DR) and retinal pathology not directly associated with diabetes and to identify factors associated with best performance.Methods: Forty-five orthoptists completed a survey comprising questions regarding their workplace experiences, plus a photo evaluation task with 36 digital fundus images.Results: We found that orthoptists' overall performance in detecting the presence of abnormality in a series of DR images was high, the mean sensitivity being 86% and specificity 91%. The sensitivity was lower for images with minimal non-proliferative DR, but higher for those with mild–moderate and severe grades of DR. No factors were predictive of performance on the screening task.Conclusions: Orthoptists performed extremely well, meeting the guidelines for DR screening recommended by National Health and Medical Research Council. The results indicate that orthoptists could potentially be used in DR screening models in Australia.
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ABSTRACT: To compare the respective performances of digital retinal imaging, fundus photography and slit-lamp biomicroscopy performed by trained optometrists, in screening for diabetic retinopathy. To assess the potential contribution of automated digital image analysis to a screening programme. A group of 586 patients recruited from a diabetic clinic underwent three or four mydriatic screening methods for retinal examination. The respective performances of digital imaging (n=586; graded manually), colour slides (n=586; graded manually), and slit-lamp examination by specially trained optometrists (n=485), were evaluated against a reference standard of slit-lamp biomicroscopy by ophthalmologists with a special interest in medical retina. The performance of automated grading of the digital images by computer was also assessed. Slit-lamp examination by optometrists for referable diabetic retinopathy achieved a sensitivity of 73% (52-88) and a specificity of 90% (87-93). Using two-field imaging, manual grading of red-free digital images achieved a sensitivity of 93% (82-98) and a specificity of 87% (84-90), and for colour slides, a sensitivity of 96% (87-100) and a specificity of 89% (86-91). Almost identical results were achieved for both methods with single macular field imaging. Digital imaging had a lower technical failure rate (4.4% of patients) than colour slide photography (11.9%). Applying an automated grading protocol to the digital images detected any retinopathy, with a sensitivity of 83% (77-89) and a specificity of 71% (66-75) and diabetic macular oedema with a sensitivity of 76% (53-92) and a specificity of 85% (82-88). Both manual grading methods produced similar results whether using a one- or two-field protocol. Technical failures rates, and hence need for recall, were lower with digital imaging. One-field grading of fundus photographs appeared to be as effective as two-field. The optometrists achieved the lowest sensitivities but reported no technical failures. Automated grading of retinal images can improve efficiency of resource utilization in diabetic retinopathy screening.Diabetic Medicine 08/2003; 20(7):528-34. · 3.24 Impact Factor
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ABSTRACT: Although regular screening for diabetic retinopathy with ophthalmoscopy or retinal photography is widely recommended in the United States and Europe, few reports of its use in developing countries are available. We compared the performance of screening by retinal photography with that of indirect ophthalmoscopy by using data from a population-based survey of diabetes and its complications in Egypt. During that project, 427 persons with diabetes underwent an eye examination and fundus photography with a non-mydriatic camera through a dilated pupil. Data from the examinations of the right eye of each patient are presented. Ninety-two (22%) of the 427 retinal photographs were ungradable; in 58 eyes (63%), this was due to media opacity (42 eyes with cataract, 3 with corneal opacity, and 13 with both). Agreement between retinal photography and indirect ophthalmoscopy was poor (kappa = 0.33; 95% CI = 0.27-0.39) and primarily due to the large number of eyes (n = 79) with ungradable photographs that could be graded by ophthalmoscopy. None of these eyes was judged by ophthalmoscopy to have sight-threatening retinopathy. Fifty-four photographs were diagnosed with greater retinopathy than found on ophthalmoscopy. Retinal photography with the nonmydriatic camera through a dilated pupil is a useful method to screen for diabetic retinopathy in most adults in Egypt. However, such screening strategies have limited use in older persons and in persons with corneal disease or cataract.Diabetic Medicine 10/1998; 15(9):783-7. · 3.24 Impact Factor
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ABSTRACT: To define the test characteristics of four methods of screening for diabetic retinopathy. Four screening methods (an exam by an ophthalmologist through dilated pupils using direct and indirect ophthalmoscopy, an exam by a physician's assistant through dilated pupils using direct ophthalmoscopy, a single 45 degrees retinal photograph without pharmacological dilation, and a set of three dilated 45 degrees retinal photographs) were compared with a reference standard of stereoscopic 30 degrees retinal photographs of seven standard fields read by a central reading center. Sensitivity, specificity, and positive and negative likelihood ratios were calculated after dichotomizing the retinopathy levels into none and mild nonproliferative versus moderate to severe nonproliferative and proliferative. Two sites were used. All patients with diabetes in a VA hospital outpatient clinic between June 1988 and May 1989 were asked to participate. Patients with diabetes identified from a laboratory list of elevated serum glucose values were recruited from a DOD medical center. The subjects (352) had complete exams excluding the exam by the physician's assistant that was added later. The sensitivities, specificities, and positive and negative likelihood ratios are as follows: ophthalmologist 0.33, 0.99, 72, 0.67; photographs without pharmacological dilation 0.61, 0.85, 4.1, 0.46; dilated photographs 0.81, 0.97, 24, 0.19; and physician's assistant 0.14, 0.99, 12, 0.87. Fundus photographs taken by the 45 degrees camera through pharmacologically dilated pupils and read by trained readers perform as well as ophthalmologists for detecting diabetic retinopathy. Physician extenders can effectively perform the photography with minimal training but would require more training to perform adequate eye exams. In this older population, many patients did not obtain adequate nonpharmacological dilation for use of the 45 degrees camera.Diabetes Care 07/1993; 16(6):889-95. · 7.74 Impact Factor