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Xanthopsia is a color vision deficiency in which there is a dominantly yellow bias in vision due to a yellowing of the optical media of the eye. The most common causes are digoxin's inhibitory action on the sodium pump, and the development of cataracts which can cause a yellow filtering effect.
Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. It typically affects both eyes, as it is not a problem specific to one eye. [5] [6] The affected area flickers but is not dark. It then gradually expands outward ...
Achromatopsia, also known as rod monochromacy, is a medical syndrome that exhibits symptoms relating to five conditions, most notably monochromacy.Historically, the name referred to monochromacy in general, but now typically refers only to an autosomal recessive congenital color vision condition.
A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mammalian eye has a scotoma in its field of vision, usually termed its blind spot.
The dots are usually black/gray on a white background and gray/white on a black background; however, they can also be transparent, white flashing, or colored. Presence of at least 2 additional visual symptoms of the 4 following categories: i. Palinopsia. At least 1 of the following: afterimages or trailing of moving objects. ii.
The fundus presents with yellow or gray lesions (white dots) at the level of the choroid and retinal pigment epithelium. The size of the white dots are between 50 and 500 micrometres and localized in the macula. The disease is characterized by vitritis and anterior chamber inflammation. Decreased vision due to vitreous inflammation may occur.
These oval or round shaped pigmented spots are formed due to RPE proliferation. [5] As the haemoglobin within the hemorrhage breaks down over time, yellow spots known as iridescent bodies are formed within the layers of the sensory retina. [5] Maculopathy occurs in a significant portion of patients affected by sickle cell retinopathy. It is ...
The pigment-producing cells that contribute to the yellow spots of some sub-species are called xanthophores. [30] It appears that the fully-black phenotypes do not ever develop these xanthophores. [31] Alpine salamanders produce a toxin from their skin, and both fully melanistic, black salamanders and spotted individuals produce the compound. [32]