Visual disturbances are defined as irregularities in one’s line of sight. Most often than not, visual disturbances are connected with neurological problems. Muscular disorders, vascular diseases, cancer, or even trauma could be potential reasons for the occurrence of visual disturbances.
People suffering from diabetes and hyperthyroidism could also be affected by visual irregularities. Sometimes these abnormalities of sight may also be genetic in nature. When visual disturbances are correlated with neurological disorders, the symptoms experienced are double vision (diplopia), hazy vision due to nystagmus that is the involuntary fast movement of the eyes, decline in visual acuity, reduced visual field, and partial or full vision loss.
Diplopia, commonly referred to as double vision results in the perception of dual images. The two fundamental reasons for double vision include a physical alteration in the lens, conjuctiva, or retinal surface and the incompetence of the brain to cover images viewed by both the eyes. Diplopia caused due to the first reason involves only a single eye whereas the latter results in binocular diplopia involving both the eyes. The 3 cranial nerves involved in double vision are namely; the oculomotor nerve (3rd cranial nerve), the abducens nerve (6th cranial nerve), and the trochlear nerve (4th cranial nerve). Nystagmus is another type of visual disturbance that is characterized by abnormal movement of the eyes, consequently leading to hazy vision.
Under normal circumstances, the eye movements are carried out by means of the neuronal connections between the eyes, brain stem, and the cerebellum. Any alterations in the central nervous system or peripheral labyrinthine apparatus result in unrestrained and recurring eye movements. Nystagmus could be of several types. There are some that involve horizontal eye movement, while some other cases demonstrate vertical nystagmus. Rotary form of the disorder is also prevalent.
The term blindness encompasses the loss of partial or complete vision. The most prominent causes of blindness include glaucoma, cataracts, and diabetic retinopathy. Some of the other causes of blindness are eye diseases, disorders related to the optic nerves, or brain diseases that affect the visual pathways or the occipital lobe of the brain. Within the US, macular degeneration is rated as the chief cause of blindness amongst those who are above 55 years of age. The inflammation of the optic nerve illustrated by the medical condition of papilledema could either be caused due to escalation in intracranial pressure or deterioration of the optic nerve.
While a brain tumor, blood clots in the brain, brain swelling or a disruption in the flow of cerebrospinal fluid contribute towards the former reason; swelling, inappropriate blood supply to the optic nerves, and diseases like multiple sclerosis result in the wear and tear of the optic nerve.
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