Exam room, chair side evaluation of retinal edema: Improving accuracy and precision for identification of subclinical diabetic macular edema

BackgroundEarly detection of diabetic macular edema (DME) is important for improving patient outcomes. Currently, the gold standards are slit lamp stereo biomicroscopy examination and fluorescein angiography (FA). Detecting DME with a slit lamp is subjective and can be difficult in the early stages of the disease. FA is invasive and involves discomfort and risk to the patient. A new diagnostic test, the Heidelberg Retina Tomograph (HRT) Retina Module (Heidelberg Engineering, Heidelberg, Germany), is noninvasive, objective, and sensitive to early changes in the retina. It is purported to locate and quantify retinal edema such as DME, independent of retina thickening. Presented are a series of case reports comparing retinal photography, FA, HRT, and ocular coherence tomography (Stratus OCT; Carl Zeiss Meditec, Jena, Germany) results on patients with DME. The purpose is to determine the clinical utility of the HRT for discerning DME compared with clinical stereo biomicroscopy impression and FA.Case reportsIn this representative case series, the author’s first stereo biomicroscopy impression, macular photographs, retinal fluorescein angiographs, Stratus OCT images, and HRT Retina Module images from 5 type 2 diabetic patients (3 insulin and 2 non–insulin dependent) with retinopathy are presented. All patients are men, with a mean age of 56.4 (range, 51 to 62). Subjects had diabetes mellitus type 2 for an average of 14.4 years (range, 10 to 22) and were experiencing fluctuations or loss in vision. In all cases, DME was clearly identifiable on FA although sometimes questionable by stereo biomicroscopy. Nonstereo retinal photos and OCT examinations were inconclusive or unremarkable in 4 of 5 cases. The HRT Edema surrogate “e” index and map results showed areas of DME that were very similar to those of the FA images.ConclusionsIn this case series, the HRT Retina Module provided useful clinical information on DME patients including the quantification and extent of both subclinical and clinically significant DME. Although more rigorous study is warranted, such immediate feedback from a noninvasive, safe, diagnostic tool is invaluable in clinical practice, particularly with the advent of prophylactic nutritional genistein-based multivitamin supplements such as Bausch & Lomb Ocuvite DF (Rochester, New York).