Discovering optimal telemedicine strategies for evaluating diabetic retinopathy

Screening for diabetic retinopathy: 1 and 3 nonmydriatic 45-degree digital fundus photographs vs 7 standard early treatment diabetic retinopathy study fields

PURPOSE

To evaluate if simple- or multiple-field digital color nonmydriatic (NM) retinal images can replace 7 standard stereoscopic fundus photographs in the screening of diabetic retinopathy (DR).

DESIGN

Prospective, masked, comparative case series.

METHODS

One hundred and eight eyes of 55 diabetics were studied to determine single lesions and to grade clinical levels of DR and diabetic macular edema (DME) using both 1 and 3 NM digital color retinal images compared with the Early Treatment Diabetic Retinopathy Study (ETDRS) 7 standard 35-mm stereoscopic color fundus photographs (7F-ETDRS). All eyes underwent NM 45-degree field images of 1 central field (1F-NM), NM 45-degree field images of 3 fields (3F-NM), and, after pupil dilatation, 30-degree 7F-ETDRS photography. Images were analyzed by 2 independent, masked retinal specialists (S.V. and E.B.), lesion-by-lesion according to the ETDRS protocol and for clinical severity level of DR and DME according to the international classification of DR.

RESULTS

Using 7F-ETDRS as the gold standard, agreement was substantial for grading clinical levels of DR and DME (kappa = 0.69 and kappa = 0.75) vs 3F-NM; moderate for DR level (kappa = 0.56) and substantial for DME (kappa = 0.66) vs 1F-NM; almost perfect for detecting presence or absence of DR (kappa = 0.88) vs both 1F-NM and 3F-NM; and almost perfect for presence or absence of DME (kappa = 0.97) vs 3F-NM and substantial (kappa = 0.75) vs 1F-NM. Sensitivity and specificity for detecting referable levels of DR were 82% and 92%, respectively, for 3F-NM and 71% and 96%, respectively, for 1F-NM.

CONCLUSIONS

Three color 45-degree NM fundus fields may be an effective tool in a screening setting to determine critical levels of DR and DME for prompt specialist referral. One central 45-degree image is sufficient to determine absence or presence of DR and DME, but not for grading it.

Mobile digital fundus screening of type 2 diabetes patients in the Finnish county of South-Ostrobothnia

In 1999 we introduced a digital, mobile eye fundus camera for screening type 2 diabetes mellitus patients (adult onset diabetes) in the Finnish county of South-Ostrobothnia. Prior to this, eye fundus examinations were only available in the regional central hospital, and no systematic screening of type 2 (adult onset) diabetes patients was possible. The total number of screenings carried out with the mobile equipment from 1999 to 2006 was 17,471 cases. There were significant benefits, most important from improved coverage of type 2 diabetes patients. Because the mobile system made eye fundus examinations available to patients in their nearest health centre, approximately 85% of all patients with diabetes in the region are now screened. On average this means that each patient is screened once every 2.5 years, which is in line with national recommendations. As a result, more of the earlier stage retinopathy cases have been diagnosed. There have also been changes in the frequency and type of procedures at the eye department of the regional central hospital. The number of cases referred to the eye department for follow-up studies has decreased from 49 in 2000 to 19 in 2005. The screening system adopted in South-Ostrobothnia has had beneficial effects for both patients and health-care providers.