Abstract
Purpose: :
Advances in optical imaging and in particular Spectral Domain Optical Coherence Tomography (SD-OCT), allow a precise visualization of the retina in age-related macular degeneration (AMD). New peculiar, well-defined, round or elongated structures can be depicted with SD-OCT scans in AMD patients The aim of this case study is to describe their OCT appearance, and their evolution over time in a series of AMD patients.
Methods: :
All patients presenting with AMD, either dry or exudative at any stage of evolution, and examined along with a period of one month were included in this prospective case study. Every patient underwent a SD-OCT examination (Spectralis, Heidelberg, Germany), including a mapping of the macular region, constituted by 37 high-resolution scans, spaced by 120 µm and centered on the macula. In case of detection of a morphological abnormality of the retina, three averaged scans were performed on the observed abnormality. Patients presenting OCT retinal abnormalities were followed-up during a period of 6 months. The initials SD-OCT scans were analyzed in their clinical features and compared with the six-months follow-up ones.
Results: :
67 eyes were included (50 exudative eyes, 17 atrophic eyes). In 48% of cases, SD-OCT revealed intraretinal hypo-reflective round or elongated cystic structures with a hyper-reflective border. Because of their shape and location, they can be referred as retinal cysts (RC). Hyper-reflective puntuate deposits could be observed inside or along the borders of this cysts. The cystic lesions were localized at the level of the outer nuclear layer and above a fibrotic area or on an atrophic portion of the complex choriocapillaris/retinal pigment epithelium. RC did not change in shape and size over 6 month time period, or after anti-VEGF treatment.
Conclusions: :
RC are a new SD-OCT finding, observed in a large majority of late stage AMD patients. Early AMD eyes seem to be spared from this feature. In more advanced stages of AMD (late wet and dry AMD), RC could correspond to giant cells, which carry out a phagocytosis of oxidized lipoproteins, which could take their origin from scarring neovascularization or degenerative processes of external retina in dry AMD. RC represent though an anatomic degenerative/scarring retinal changes; they are not a sign of exudation and hence do not require any treatment.
Keywords: age-related macular degeneration • imaging/image analysis: clinical • lesion study