Tele-Screening for Diabetic Retinopathy With the Retinal Thickness Analyzer

Abstract

OBJECTIVE -To compare the effectiveness of tele-screening using a novel enhanced retinal thickness analyzer (RTA) with onsite routine ophthalmologic examination for diabetic retinopathy. RESEARCH DESIGN AND METHODS-A consecutive series of 31 eyes from diabetic patients were included. All underwent ophthalmologic examination, including stereoscopic dilated funduscopy and scanning with the RTA. The RTA reports consisted of a wide-angle, red-free fundus photograph and a macular-region retinal thickness map. Reports were graded by three independent graders in a masked manner. The diagnoses of proliferative retinopathy, macular edema, and treatment decisions made by the RTA graders and the clinical examiner were compared.RESULTS -On clinical examination 5 of 31 eyes were diagnosed with proliferative diabetic retinopathy (PDR). All five were referred for treatment by two graders and four eyes by one grader. All eyes with PDR and 12 of the 26 eyes with nonproliferative diabetic retinopathy showed severe macular edema. Seven of the 12 eyes with macular edema were clinically eligible for focal laser treatment, and all of them were detected by all RTA graders. Macular thickening was detected in eight eyes by RTA where no treatment was necessary, as judged by clinical examination. Thus, sensitivity was 93% (mean) for detecting PDR and 100% for detecting macular edema, with a specificity of 58 -96% depending on the grader. The RTA did not allow valid assessment due to poor image quality in only one case.CONCLUSIONS -Screening for diabetic retinopathy with a combination of wide-angle fundus photography and macular thickness mapping by an objective method, such as optical coherence tomography or the RTA, offers the prerequisites for establishing a successful telescreening program. Diabetes Care 26:2890 -2897, 2003D iabetic retinopathy is a leading cause of visual impairment and blindness in developed countries. Macular edema is the major cause of vision loss in diabetic patients, while proliferative retinopathy is another common cause (1). An annual clinical examination of dilated pupils by an ophthalmologist is the current gold standard of care for reducing diabetes-related ocular complications in patients with no or mild diabetic retinopathy (2). In the Early Treatment Diabetic Retinopathy Study (ETDRS), this led to a reduction of moderate visual loss by 50% (3).In many countries, an effective population-based screening cannot be offered by ophthalmologists and is performed by optometrists or general practitioners (4). One possible way to increase the number of ophthalmologically monitored diabetic patients is teleophthalmologic examination by a specialist (5-9). The gold standard of photographic documentation consists of seven stereoscopic fundus photographs, as defined by the ETDRS, requiring expensive equipment and a skilled photographer (10). Consequently, a number of alternative photographic methods have been evaluated for this purpose and are potentially able to identify patients requiring laser treatment (11).Recentl...

Repeatability and reproducibility of optic nerve head topography using the retinal thickness analyzer

“…They reported no significantly different reproducibility of topographic data (measured by coefficients of variation) between the RTA and the HRT II. Recently, Neubauer and colleagues [16] reported high intraclass correlation coefficients, but by analyzing the coefficients of variance (not performed in their paper), the results are comparable to ours, with CVs ranging from 17% for the best parameter disk area to 63% for the worst parameter cup volume (see Table 4). ICCs are frequently used as a measure of reliability of a variable.…”

“…The retinal thickness analyzer has been tested for reproducibility of macular thickness in several studies [11,17,20]. Only two studies have been published on the reproducibility of optic disk topography using the RTA [10, 16]. Itai and colleagues [10] published a study of optic disk topography measured by the RTA in comparison to measurements obtained with the Heidelberg retina tomograph II.…”

Age Effect on Retina and Optic Disc Normal Values

“…The validity of optic disc measurements by RTA has previously been shown [13] and its repeatability [23] is known to be similar to that of confocal scanning microscopy with the HRT [24,25] . However, all absolute measurements of the RTA differ from those obtained by HRT, which is obvious for the optic disc size.…”

Evolutionary algorithm based classifier parameter tuning for automatic diabetic retinopathy grading: A hybrid feature extraction approach

“…It yielded a mean sensitivity of 93% for PDR and 100% sensitivity for detecting diabetic macular edema (DME) as compared to specificities ranging from 58 to 96% during clinical examination. The topography of the OD was found to be highly reproducible and can be used for glaucoma diagnostics [41].…”