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In NPCB survey (2001–2002) Corneal opacity was the 6th major cause of blindness in India, which accounts for 0.9% of total blind population. In the RAAB (Rapid Assessment of Avoidable Blindness) survey (2006–2007) Corneal opacity including Trachoma was mentioned as the second major cause of blindness, which accounts for 6.5% of total blindness.
A scotoma may include and enlarge the normal blind spot. Even a small scotoma that happens to affect central or macular vision will produce a severe visual disability, whereas a large scotoma in the more peripheral part of a visual field may go unnoticed by the bearer because of the normal reduced optical resolution in the peripheral visual field.
Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception.In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficulties with normal daily tasks, including reading and walking. [6]
Leber's congenital amaurosis (LCA) is the most severe and earliest of the inherited retinal dystrophies that cause congenital blindness. It has an incidence of 2-3 per 100,000 births and accounts for 10-18% of cases of congenital blindness among children in blind institutes and 5% of all retinal dystrophies, a figure that is likely to be greater in countries with a greater percentage of ...
Cortical blindness is the total or partial loss of vision in a normal-appearing eye caused by damage to the brain's occipital cortex. [1] Cortical blindness can be acquired or congenital, and may also be transient in certain instances. [ 2 ]
Treatment is based on the cause of the retinopathy and may include laser therapy to the retina. Laser photocoagulation therapy has been the standard treatment for many types of retinopathy. Evidence shows that laser therapy is generally safe and improves visual symptoms in sickle cell and diabetic retinopathy.
Adie's pupil, which fails to constrict in response to light; aniridia, which is absence of the iris; and albinism, where the iris is defectively pigmented, may also cause this. Central cataracts , due to the lens clouding, disperses the light before it can reach the retina and is a common cause of hemeralopia and photoaversion in the elderly.
Retinopathy of prematurity (ROP) is a cause of childhood blindness that can occur around the time of birth. Generally, measures taken to avoid preterm birth are also effective at preventing ROP. Babies delivered preterm, defined at or before 37 weeks of gestation, have incomplete development of the blood vessels supplying the retina . [ 21 ]