Hyperreflective sign in resolved cotton wool spots using high-resolution optical coherence tomography and optical coherence tomography ophthalmoscopy.

PURPOSE

To characterize retinal changes in areas of cotton wool spots (CWSs) using optical coherence tomography (OCT) and to determine the optical density changes of the retina after CWSs have disappeared clinically.

DESIGN

Prospective, noninterventional, observational study.

PARTICIPANTS

Thirty-one patients with CWSs who underwent imaging studies.

METHODS

The study groups included patients with CWSs resulting from diabetic retinopathy (n = 12), human immunodeficiency virus (HIV) retinopathy (n = 10), hypertensive retinopathy (n = 3), branch retinal vein occlusion (n = 3), uveitis (n = 2), and radiation retinopathy (n = 1). The single line scan mode of the StratusOCT Model 3000 (Carl Zeiss Meditec, Dublin, CA) was used for imaging of acute CWSs, CWSs 3 months after their resolution, and adjacent normal retina. A fundus photograph served as a template for localization of OCT scanning of CWSs. Retinal tissue reflectivity images were compared across lesion types and time. Additional imaging in 14 patients was performed to localize lesions better and to provide coronal OCT sections using the combined OCT and scanning laser ophthalmoscope.

MAIN OUTCOME MEASURES

Changes in retinal reflectivity in areas of normal retina and retina with acute and resolved CWSs.

RESULTS

The average reflectivity of normal retina was 58.4+/-2.1 dB, the average reflectivity in the area of active CWSs was 62.6+/-2.5 dB, and the average reflectivity in the same area after CWSs resolved was 61.0+/-2.4 dB. A significant difference (P<0.05) exists between reflectivity of normal retina and acute CWSs as well as normal retina and resolved CWSs.

CONCLUSIONS

Acute CWSs show a hyperreflective pattern on OCT. As they become ophthalmoscopically invisible, the OCT still shows signs of hyperreflectivity in the areas of previous CWSs (hyperreflective sign). The authors observed the same phenomenon using 2 imaging machines.