Reliability of stereoscopic nonmydriatic retinography for assessment of diabetic macular edema when performed by endocrinologists.

BACKGROUND

Diabetic macular edema (DME) is the main cause of moderate vision loss in type 2 diabetes. Diagnosis is achieved by dilated fundus examination or by measuring retinal thickness. However, it can be identified in nonmydriatic retinography (NMR) with hard exudates as a surrogate marker or macular thickness under stereoscopic vision. To date, few studies have focused on interobserver reliability for DME with this technique.

METHODS

Fity-three type 2 diabetes patients with known diabetic retinopathy were studied. We obtained 182 pairs of stereoscopic retinographs with a nonmydriatic camera. Photographic options were 30 degrees or 45 degrees macula-centered retinal field and spontaneous or pharmacological dilation using tropicamide. An endocrinologist with a minimum of training and another with no specific training in this kind of examination diagnosed the images. DME was assumed if retinal thickness was identified within one disc diameter around the fovea.

RESULTS

The kappa index agreement between both endocrinologists for all the data was 0.16 (P = 0.02). Depending on the photographic options, all the kappa indices were below 0.25, except for the 45 degrees retinal field under spontaneous mydriasis (0.58) where the number of samples analyzed was reduced to 22.

CONCLUSIONS

In our study, endocrinologists with a low level of training did not reach a suitable level of agreement regarding the reliability of stereoscopic NMR as a technique for diagnosing DME. We feel that, as NMR can be performed by various different health providers, it would be advisable to establish generally agreed upon criteria for training staff in this technique.