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A green filter ~540–570 nm is used to block out red wavelengths of light. This allows a better contrast for viewing retinal blood vessels and associated hemorrhages, pale lesions such as drusen and exudates, and subtle characteristics such as nerve fibre layer defects and epiretinal membranes. [12]
Drusen, from the German word for node or geode (singular, "Druse"), are tiny yellow or white accumulations of extracellular material that build up between Bruch's membrane and the retinal pigment epithelium of the eye. The presence of a few small ("hard") drusen is normal with advancing age, and most people over 40 have some hard drusen. [1]
The optic nerve is a cable connection that transmits images from the retina to the brain. It consists of over one million retinal ganglion cell axons. The optic nerve head, or optic disc is the anterior end of the nerve that is in the eye and hence is visible with an ophthalmoscope. It is located nasally and slightly inferior to the macula of ...
The macula (/ˈmakjʊlə/) [1] or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around 5.5 mm (0.22 in) and is subdivided into the umbo, foveola, foveal avascular zone, fovea, parafovea, and perifovea areas.
Advanced retinopathy lesions, such as microaneurysms, blot hemorrhages and/or flame hemorrhages, ischemic changes (e.g. "cotton wool spots"), hard exudates and in severe cases swelling of the optic disc (optic disc edema), a ring of exudates around the retina called a "macular star" and visual acuity loss, typically due to macular involvement.
Age-Related Macular Degeneration is a degenerative maculopathy associated with progressive sight loss. It is characterised by changes in pigmentation in the Retinal Pigment Epithelium, the appearance of drusen on the retina of the eye and choroidal neovascularization. AMD has two forms; 'dry' or atrophic/non-exudative AMD, and 'wet' or ...
Stargardt disease is the most common inherited single-gene retinal disease. [1] In terms of the first description of the disease, [2] it follows an autosomal recessive inheritance pattern, which has been later linked to bi-allelic ABCA4 gene variants (STGD1).
Cone dystrophy; Fundus of a 45 year-old patient with cone rod dystrophy segregating with a loss-of-function mutation (E1087X) in ABCA4. Note the presence of various-shaped pigment deposits in the posterior pole with atrophy of the retina, while the retina appears less damaged in periphery (upper part of the photograph).