Light‐induced modifications of the outer retinal hyperreflective layers on spectral‐domain optical coherence tomography in humans: an experimental study

International audiencePurposeNumerous small hyperreflective dots (HRDs) can be seen within the hyporeflective layer between the ellipsoid zone (EZ) and the interdigitation zone (IZ) on C-scan spectral-domain optical coherence tomography (SD-OCT) with a yet unknown variation under light conditions. The aim of this study was to explore light-induced SD-OCT changes in these HRDs.MethodsThe study subjects were randomly assigned to two groups: Group 1 experienced a dark adaptation protocol followed by intense retinal photobleaching, while Group 2, serving as the control group, was exposed to constant ambient light without any variation. The number of HRDs was automatically counted.ResultsTwenty healthy volunteers were prospectively included. The number of HRDs differed significantly over time (p = 0.0013). They decreased in Group 1 after dark adaptation and retinal photobleaching before returning to baseline levels 30 min later; conversely, they remained relatively constant in Group 2 throughout the study (p < 0.001). Light-skinned subjects had less HRD than dark-skinned subjects.ConclusionWe observed light-induced modifications in the space between the EZ and the IZ. We hypothesize that the HRDs visible in this zone correspond to melanosomes that are mobilized during the light stimulation protocol. Larger studies are recommended to further evaluate and confirm light-induced SD-OCT changes under physiological and pathological conditions

Assessment of Spontaneous Retinal Arterial Pulsations in Acute Central Retinal Vein Occlusions

Central retinal vein occlusion (CRVO) is a common retinal disease. Recent works mentioned spontaneous retinal arterial pulsations (SRAPs) as a feature of some CRVOs. This is a retrospective study on patients presenting with CRVO who were followed up for at least 6 months. The objective was to identify SRAP in the acute phase of the disease and determine their relationship with patients’ characteristics and visual prognosis. A 10-second infrared film centered on the optic disc was recorded within a month of the onset of symptoms, and SRAPs were detected in two-thirds of the cases. Patients with SRAP were significantly younger than those without SRAP. Mean central macular thickness was significantly higher in the absence of SRAP, which was translated into a more severe macular edema; however, this difference faded with time. BCVA tended to be higher in the presence of SRAP at the 6-month follow-up when adjusted to baseline. This study demonstrates that SRAPs are a frequent finding, easily detected by infrared fundus video recording, and associated with a younger age and lesser macular edema