The estimated number of people visually impaired in the world is 285 million, 39 million blind and 246 million having low vision; 65 % of people visually impaired and 82% of all blind are 50 years and older. Global causes of blindness as percentage of global blindness in 2010 are Cataract (51%), Glaucoma (8%), Refractive Error (3%), AMD - Age related Macular Degeneration (5%), Corneal Opacity (4%), Trachoma (3%), undetermined (21%), DR - Diabetic Retinopathy (1%) and Childhood blindness (4%).
Main causes of blindness in India in the age group of 50 year and older are Cataract (62.6%), Refractive Error (19.70%), Glaucoma (5.80%), Posterior Segment Disorder (4.70%), Surgical Complication (1.20%, Posterior Capsular Opacification (0.90%), Corneal Blindness (0.90%), Others (4.19%). Estimated National Prevalence of Childhood Blindness /Low Vision is 0.80 per thousand http://npcb.nic.in/index.asp
The condition responsible for 62.60 % blindness in India.
Cataract is clouding of the lens of the eye which impedes the passage of light. Although most cases of cataract are related to the aging process, occasionally children can be born with the condition, or a cataract may develop after eye injuries, inflammation, and some other eye diseases.
The condition responsible for 19.70% of blindness in India.
Refractive errors (myopia, hypermetropia, astigmatism, presbyopia) result in an unfocussed image falling on the retina. Uncorrected refractive errors, which affect persons of all ages and ethnic groups, are the main cause of vision impairment. They may result in lost education and employment opportunities, lower productivity and impaired quality of life.
The condition responsible for 5.80 % blindness in India.
Glaucoma is the second leading cause of blindness and the leading cause of irreversible blindness worldwide.
The term ‘glaucoma’ relates to a group of conditions that can be classified in a variety of ways, but all of which are characterised by optic nerve damage (often referred to as cupping) and visual field loss (often with an arcuate pattern of mid-peripheral loss), secondary to retinal ganglion cell damage and death. The most common types of glaucoma are Primary Open Angle Glaucoma (POAG) and Primary Angle Closure Glaucoma (PACG).
Posterior Segment Disorder
The condition responsible for 4.70 % blindness in India.
Everything behind the lens of the eye is called the posterior segment and is comprised of the retina and vitreous body. The vitreous body is a jellylike substance that fills the interior of the eyeball behind the lens. The retina (along with the optic nerve) is essentially brain tissue—a nerve cell that transmits vision to the brain. When light lands on the retina, the message of vision is sent to the brain by the optic nerve.
Patients at risk for retina diseases require frequent eye exams and a variety of imaging studies to assess for any signs of early damage. These diseases, if caught, can often be treated with medication, laser treatment or surgery. Treatment may prevent further damage to the retina, and is now so advanced that some damage can even be reversed.
Optimal treatment of retina and vitreous disease is best done by a fellowship-trained retina specialist with access to specialized imaging and diagnostic equipment.
Other eye conditions are responsible for 7.20 % blindness in India.
These eye conditions include Surgical Complication, Posterior Capsular Opacification, Corneal Blindness etc.