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Occult macular dystrophy (OMD) is a rare inherited degradation of the retina, characterized by progressive loss of function in the most sensitive part of the central retina , the location of the highest concentration of light-sensitive cells (photoreceptors) but presenting no visible abnormality.
Ocular OCT retinal thickness map, right eye Time-domain OCT of the macular area of a retina at 800 nm, axial resolution 3 μm Spectral-domain OCT macula cross-section scan. Optical coherence tomography (OCT) is a technique for obtaining sub-surface images of translucent or opaque materials at a resolution equivalent to a low-power microscope.
Scanning laser ophthalmoscopy developed as a method to view a distinct layer of the living eye at the microscopic level. The use of confocal methods to diminish extra light by focusing detected light through a small pinhole made possible the imaging of individual layers of the retina with greater distinction than ever before. [4]
The Heidelberg Retinal Tomography is a diagnostic procedure used in ophthalmology. The Heidelberg Retina Tomograph (HRT) is an ophthalmological confocal point scanning laser ophthalmoscope [ 1 ] for examining the cornea and certain areas of the retina using different diagnostic modules (HRT retina, HRT cornea, HRT glaucoma).
Characteristically, the abnormal vessels are localized and the retinal blood vessels peripheral to the abnormal ones seemingly have failed to develop and are thus not seen. In some eyes, retinal vessels form small nodules on the surface of the retina, known as angiomas. [1] These can bleed and be attached to the vitreous humour.
A short scan time prevents too much patient movement during signal acquisition. With the development of Fourier-domain OCT, spectral-domain OCT, and swept source signal acquisition time was greatly improved making OCTA possible. [40] OCTA scan time is now around three seconds, however, saccadic eye movement still causes a low signal-to-noise ratio.
[8] [16] On B-scan ultrasonography, a detached retina typically appears as a membrane floating in the vitreous cavity, moving in a wave-like motion. [19] OCT can detect fluid behind the retina, involvement of the macula (the central part of the retina), and other abnormalities within the retinal layers. [8] [20]
Fundus photographs are also used to document abnormalities of disease process affecting the eye, and/or to follow up on the progress of the eye condition/disease such as diabetes, age-macular degeneration (AMD), glaucoma, multiple sclerosis, and neoplasm of the choroid, cranial nerves, retinal or eyeball.