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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]
There is a blind spot at the optic disc because there are no rods or cones beneath it to detect light. The central retinal artery and vein can be seen in the middle of the disc as it exits the scleral canal with the optic nerve to supply the retina. The vessels send branches out in all directions to supply the retina.
The protrusion extends beyond the plane of the eyelid margins and it can be unilateral or bilateral. Lattice corneal dystrophy: Lattice corneal dystrophy is an autosomal-dominant characterized by amyloid deposition in the corneal stroma. Due to deposits, lattice-like corneal opacities may occur in stroma.
This pattern can be revealed via visual field testing. Upon examination, the pupils usually demonstrate a normal response to light and near stimulation. In those who are practically blind, the pupils will be dilated with a weak or absent response to light. The optic disc may appear normal, swollen, or hyperemic in early stages.
Choroidal nevus with drusen can be considered as a sign of chronicity since drusen take years to develop and appear. [14] Drusen are composed of lipids and can actually be an indicator that a tumour is a benign nevus as opposed to a cancerous melanoma. [15] In nevi imaged by OCT, about 41% are found to have drusen. [16]
Obscured vision due to papilledema may last only seconds, while a severely atherosclerotic carotid artery may be associated with a duration of one to ten minutes. [6] Certainly, additional symptoms may be present with the amaurosis fugax, and those findings will depend on the cause of the transient monocular vision loss.
Geographic atrophy (GA), also known as atrophic age-related macular degeneration (AMD) or advanced dry AMD, is an advanced form of age-related macular degeneration that can result in the progressive and irreversible loss of retinal tissue (photoreceptors, retinal pigment epithelium, choriocapillaris) which can lead to a loss of central vision over time.
Dystrophy of the light-sensing cells of the eye may also occur in the rods as well, or in both the cones and the rods. A type of rod-cone dystrophy—where rod function decline is typically earlier or more pronounced than cone dystrophy—has been identified as a relatively common characteristic of Bardet–Biedl Syndrome .