To evaluate hyperreflective retinal spots (HRS), in normal subjects and diabetic patients without and with macular edema (diabetic macular edema, DME), on linear B-scans and corresponding en face image of spectral-domain optical coherence tomography.
Retrospective evaluation of images of 54 eyes/subjects (16 normal subjects, 19 diabetic patients without DME, and 19 with DME). On horizontal B-scan spectral-domain optical coherence tomography, passing through the center of the fovea, the following characteristics of HRS were evaluated: location (inner retina or outer retina), size (≤30 or >30 μm), reflectivity (similar to nerve fiber layer or to retinal pigment epithelium–Bruch complex), and presence or absence of back shadowing. On en face spectral-domain optical coherence tomography, the following patterns were evaluated: 1) isolated HRS (not corresponding to any visible lesion); 2) HRS corresponding to a segment of retinal capillary or microaneurysm wall; and 3) HRS corresponding to hard exudate. All gradings were performed twice by two graders in a masked fashion.
Size ≤30 μm, reflectivity similar to nerve fiber layer, and absence of back shadowing were associated with absence of vessels or any other lesion on en face image (P = 0.0001 for all). Size >30 μm, reflectivity similar to retinal pigment epithelium–Bruch complex, presence of back shadowing, and location in the outer retina were all associated with presence of hard exudate on en face imaging (P < 0.0001 for all). Multiple logistic regression analysis showed that HRS present in the inner retina (P < 0.0001), size >30 μm (P = 0.0029), and presence of back shadowing (P < 0.0001) are directly associated with presence of microaneurysms on en face image. Intragrader and intergrader repeatability were excellent for all evaluations.
Hyperreflective retinal spots ≤30 μm, reflectivity similar to nerve fiber layer, and absence of back shadowing may represent activated microglial cells; HRS >30 μm, reflectivity similar to retinal pigment epithelium–Bruch complex, presence of back shadowing, and location in the outer retina may represent hard exudate; HRS >30 μm, presence of back shadowing, and location in the inner retina may represent microaneurysms. These hypotheses may be tested in further studies.
Hyperreflective retinal spots visible on spectral-domain optical coherence tomography with specific characteristics, such as size, location, absence of back shadowing, and intensity of hyperreflectivity, may become a new biomarker of retinal inflammation in diabetic patients with and without macular edema.
*Department of Ophthalmology, University of Padova, Padova, Italy;
†University Campus Biomedico, Roma, Italy; and
‡Fondazione G. B. Bietti, IRCCS, Roma, Italy.
Reprint requests: Edoardo Midena, MD, PhD, Department of Ophthalmology, University of Padova, Via Giustiniani 2, Padova 35128, Italy; e-mail: email@example.com
Supported by, as GB Bietti Foundation is concerned, the Ministry of Health and Fondazione Roma. This study was mainly supported by the grant from the 7th Frame-work Programme (EUROCONDOR. FP7-278040).
None of the authors have any conflicting interests to disclose.