The list of disorders resulting in diminished vision is huge. Disturbance of vision can result from an uncorrected refractive error, disease or injury of the cornea, iris, lens, vitreous, retina, choroid or sclera of the eye. It may also result from disease or injury to the structures comprising the visual pathway from the retina to the occipital cortex and from lesions of the structures around the eye for example, swollen lids, drooping eyelids.
The prevalent anomalies affecting vision are refractive errors, including astigmatism (an irregular front eye curvature), myopia (nearsightedness), and hypermetropia (farsightedness). These conditions can usually be rectified with eyeglasses or contact lenses. Additional vision impairments encompass amblyopia (commonly known as lazy eye), diplopia (double vision), as well as various disorders affecting the eye, optic nerve, neural pathways between optic nerves and the brain, and even brain-related issues.
The clarity of the eye can diminish due to corneal opacities, cataracts, or vitreous haemorrhage (bleeding within the gel-like substance behind the lens). Flaws situated close to the retina’s center result in the loss of corresponding segments of the visual field. While generally inconsequential, floaters might suggest a retinal tear or bleeding, and could even be an early sign of retinal detachment. Optic neuritis (inflammation of the optic nerve) can create a blind spot at the center of the visual field.
Injuries to the brain, like those resulting from a stroke, can lead to visual deficits such as hemianopia (loss of half the visual field), agnosia (inability to recognize objects), visual perseveration (where a scene persists even after shifting gaze), and visual hallucinations.