Hyporeflective Areas Research Articles

Suivi d’un cas de maculopathie solaire par OCT

Solar maculopathy is caused by sun-gazing without protection and in most cases appears to be reversible. Retinal damage may be caused by photochemical changes combined with a rise in temperature at the time of sun observation. We report a case of bilateral solar retinopathy following direct sun gazing after observation of the partial eclipse on 3 October 2005. A 25-year-old Caucasian man presented 24 h after watching the eclipse with symptoms of blurred vision and a bright positive central scotoma. Total direct viewing time was approximately 5 min. While observing the eclipse, the patient kept both eyes open. On presentation, his visual acuity was 20/25 in his right eye and 20/32 in his left eye. Ophthalmoscopic examination revealed a bilateral yellowish-white spot in the center of the foveal region. Static visual field examination did not disclose any absolute scotoma but a decrease in the foveal threshold was noted in both eyes. Optical coherence tomography (OCT) examination revealed a bilateral increased reflectivity of the inner foveal retina that was greater in the left eye. This finding was associated with a hyporeflective area of the underlying retinal pigment epithelium: choriocapillaris complex and an increase in retinal thickness. Eight days later, visual acuity was 20/20 in each eye. Funduscopy showed the yellow lesion had vanished. Four months after exposure, funduscopy was normal and OCT scan showed normal reflectivity of all retinal layers in the fovea. However, static visual field examination disclosed a decreased foveal threshold on the left eye. We compare the OCT findings in this patient with the data reported in the literature. Indeed, various OCT findings have been reported depending on the intensity and frequency of sun exposure. This observation demonstrates that OCT appears to be potentially useful in the evolutive follow-up of solar maculopathy, and emphasizes the importance of eye safety during solar eclipse observation.

Enhanced visualization of acute macular neuroretinopathy by Heidelberg Retina Tomography

We report Heidelberg Retina Tomography (HRT) findings in a case of bilateral acute macular neuroretinopathy in a 22-year-old man. In addition to fundus photography, fluorescein and indocyanine green angiography, and visual field testing, HRT scans of the macula were performed early in the disease and at a follow up of 2 months. We found typical paracentral scotomata in visual field testing corresponding to sharply delineated, hyporeflective areas of the macula as visualized in HRT II scans. Those lesions were almost invisible on regular fundus photographs. Angiography results were unremarkable. The lesion size decreased over time. The visibility of the lesions was markedly enhanced by HRT scans, thus the diagnosis and follow up of acute macular neuroretinopathy could be facilitated by this non-invasive imaging technique.

Imaging the Microstructural Abnormalities of Meesmann Corneal Dystrophy by In Vivo Confocal Microscopy

To delineate the microstructural features of Meesmann corneal dystrophy using in vivo confocal microscopy. Three subjects with clinically diagnosed Meesmann corneal dystrophy were examined by slit-lamp biomicroscopy and slit-scanning in vivo confocal microscopy. On slit-lamp biomicroscopy, all subjects demonstrated large bilateral multiple epithelial cystic lesions extending to the midperiphery. On in vivo confocal microscopy, these lesions appeared as hyporeflective areas in the basal epithelial layer. The majority were circular, oval or teardrop shaped and ranged between 48 mum and 145 mum in diameter. Large elongated intraepithelial clefts were also seen. Reflective spots were visible within most of the lesions and these may represent the fibrillogranular material (termed peculiar substance) and tonofilament bundles observed in electron microscopy studies. An additional finding was the fragmented appearance of the subbasal nerve plexus. We present the first case series of Meesmann corneal dystrophy imaged by in vivo confocal microscopy and describe the associated microstructural features. Delineation of these features facilitates the use of the confocal microscope to aid diagnosis and management of corneal dystrophies.

Experimental Imaging of Intracorneal Ring Segments With Optical Coherence Tomography

To investigate the imaging of corneal structures with optical coherence tomography (OCT) after implantation of intracorneal ring segments (ICRS). In an experimental study with six porcine eyes, qualitative and quantitative imaging with corneal OCT using a wavelength of 1310 nm after implantation of ICRS was performed. The optical results were compared with light microscopy of the histological sections. In corneal OCT, the ICRS revealed marked hyporeflective intrastromal areas, which correlated well with macroscopic and microscopic findings. Corneal OCT enabled precise images of the incision depth for the implantation of ICRS, and the exact intrastromal segment position. Noncontact slit lamp-adapted corneal optical coherence tomography could be employed to clinically monitor corneal changes after implantation of ICRS, evaluate the depth of the segments to correlate refractive changes, and quantify the stromal wound healing response.

In vivo micropathology of Best macular dystrophy with optical coherence tomography

Best macular dystrophy (BMD) is an autosomal dominant retinopathy caused by mutations in the VMD2 gene that encodes a chloride channel in the basolateral membrane of the retinal pigment epithelium (RPE). BMD patients were studied using optical coherence tomography (OCT) to understand the disease process in the macula leading to vision loss. BMD patients (ages 5–61), representing four families with known VMD2 mutations, were included. OCT scans were recorded in the central retina and longitudinal reflectivity profiles were analysed. The central retina in BMD showed different OCT abnormalities at or near the level of the highly reflective deep retinal band termed the outer retina-choroid complex (ORCC). Two types of ORCC change were noted to occur either separately or together: (1) splitting with or without intervening hyporeflective areas; and (2) elevation. Longitudinal study of a BMD patient indicated that such abnormalities were dynamic and changed in type and degree with time. The pathogenetic sequence in BMD may begin with defective fluid transport across the RPE secondary to the channelopathy in the basolateral membrane. In the macula, this leads to an abnormal interface with adjacent structures at both apical and basal surfaces of the RPE. The disease process results in detachments of the neurosensory retina, such as in central serous chorioretinopathy, and sub-RPE pathology resembling some stages of age-related macular degeneration, with eventual loss of photoreceptors, inner retina and central vision.