Mechanism of reduced vision | Clinical features | Examples of causes |
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Ocular causes | ||
Refractive errors (light is not focused onto the retina) |
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Media opacity (light is obstructed from reaching the retina) |
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Retina (failure of photoreceptors or its supporting structures) |
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Optic nerve pathologies (dysfunction of optic nerve to transmit signals) | ||
Optic neuropathy (anterior to the optic chiasm) |
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Optic chiasmal lesion |
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Retrochiasmal lesion |
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AMD = age-related macular degeneration; BRAO/CRAO = branch/central retinal artery occlusion; BRVO/CRVO = branch/central retinal vein occlusion; CSR = central serous chorioretinopathy; CMV = cytomegalovirus; CVST = central venous sinus thrombosis; DMO = diabetic macular oedema; DR = diabetic retinopathy; HSV = herpes simplex virus; ICP = intracranial pressure; IIH = idiopathic intracranial hypertension; MS = multiple sclerosis; VZV = varicella zoster virus.
↵aRarely causes dyschromatopsia and relative afferent pupillary defect.