Ungradable Images Research Articles

The value of digital imaging in diabetic retinopathy

To assess the performance of digital imaging, compared with other modalities, in screening for and monitoring the development of diabetic retinopathy. All imaging was acquired at a hospital assessment clinic. Subsequently, study optometrists examined the patients in their own premises. A subset of patients also had fluorescein angiography performed every 6 months. Research clinic at the hospital eye clinic and optometrists' own premises. Study comprised 103 patients who had type 1 diabetes mellitus, 481 had type 2 diabetes mellitus and two had secondary diabetes mellitus; 157 (26.8%) had some form of retinopathy ('any') and 58 (9.9%) had referable retinopathy. A repeat assessment was carried out of all patients 1 year after their initial assessment. Patients who had more severe forms of retinopathy were monitored more frequently for evidence of progression. Detection of retinopathy, progression of retinopathy and determination of when treatment is required. Manual grading of 35-mm colour slides produced the highest sensitivity and specificity figures, with optometrist examination recording most false negatives. Manual and automated analysis of digital images had intermediate sensitivity. Both manual grading of 35-mm colour slides and digital images gave sensitivities of over 90% with few false positives. Digital imaging produced 50% fewer ungradable images than colour slides. This part of the study was limited as patients with the more severe levels of retinopathy opted for treatment. There was an increase in the number of microaneurysms in those patients who developed from mild to moderate. There was no difference between the turnover rate of either new or regressed microaneurysms for patients with mild or with sight-threatening retinopathy. It was not possible in this study to ascertain whether digital imaging systems determine when treatment is warranted. In the context of a national screening programme for referable retinopathy, digital imaging is an effective method. In addition, technical failure rates are lower with digital imaging than conventional photography. Digital imaging is also a more sensitive technique than slit-lamp examination by optometrists. Automated grading can improve efficiency by correctly identifying just under half the population as having no retinopathy. Recommendations for future research include: investigating whether the nasal field is required for grading; a large screening programme is required to ascertain if automated grading can safely perform as a first-level grader; if colour improves the performance of grading digital images; investigating methods to ensure effective uptake in a diabetic retinopathy screening programme.

Use of Joslin Vision Network digital-video nonmydriatic retinal imaging to assess diabetic retinopathy in a clinical program.

To incorporate a nonmydriatic, digital-video retinal imaging system into a Diabetes Outpatient Intensive Treatment Program and to evaluate the system's ability to assess diabetic retinopathy (DR), determine follow-up, and appropriately refer to retinal specialist ophthalmologists. Fundus images were obtained according to Joslin Vision Network (JVN) protocol and evaluated by certified JVN readers. Patients with significant retinal disease underwent evaluation by retinal specialists. A total of 268 (51.0%) of 525 imaged patients had comprehensive eye examination by a retinal specialist owing to referable JVN-assessed clinical level of DR, nondiabetic ocular disease, ungradeable images, last eye examination >/=12 months prior, or patient request for examination. JVN diagnosis of a clinical level of DR agreed exactly with clinical findings in 388 eyes (72.5%) or within one level in 478 eyes (89.3%). JVN referral based on most severe diagnosis in either eye matched retinal specialist-recommended follow-up in 248/268 of patients (92.5%). A total of 136/525 (25.9%) of JVN patients had nondiabetic ocular abnormalities requiring referral. Recommended follow-up from JVN imaging compared favorably to clinical examination by a retinal specialist. Nondiabetic ocular pathology was identified. JVN assessment of DR level compares favorably to clinical practice, potentially improving access to eye care and enhancing diabetes management.

Clinical evaluation of patients with diabetic retinopathy: Accuracy of the inoveon diabetic retinopathy-3DT system

PurposeThis study analyzed the accuracy of the Inoveon Diabetic Retinopathy (DR-3DT) system (Inoveon Corp., Oklahoma City, OK), a scalable evaluation method for the management of diabetic retinopathy using high-quality digital retinal imaging. DesignAn independent, masked, cross-sectional, clinical validation study. ParticipantsTwo hundred ninety adult patients with diabetes from the Chickasaw Nation’s Carl Albert Indian Health Facility in Ada, Oklahoma. MethodsAll participants underwent DRS7 imaging using a Zeiss FF450 fundus camera with images recorded on 35-mm film and a Kodak DCS520 digital camera back. Masked double grading with independent third reader adjudication yielded an Early Treatment Diabetic Retinopathy Study (ETDRS) Final Retinopathy Severity Scale Level (ETDRS Level) and macular edema stage for each eye. The presence of ≥ ETDRS Level 53, questionable or definite clinically significant macular edema in either eye, or ungradeable images was defined as a threshold event requiring referral. Main outcome measuresAccuracy (sensitivity, specificity, predictive values) of the digital system relative to the film “gold standard” on the threshold referral criteria per patient. ResultsAll patients with gradeable 35-mm slides from at least one eye were included in this per patient analysis (n = 290). The prevalence of threshold events was 19.3%. The sensitivity of the digital system in detecting threshold events was 98.2% (95% confidence interval [CI], 90.5%–100.0%) and specificity 89.7% (95% CI, 85.1%–93.3%). The positive predictive value was 69.5% and negative predictive value 99.5% for this sample. ConclusionsWhen compared with the “gold standard,” Inoveon’s DR-3DT system provides highly accurate diabetic retinopathy referral decisions. Given their inherent advantages, high-quality digital imaging systems could replace the film “gold standard” as the basis for scalable, accessible, diabetic retinopathy evaluation.