Causes of Blindness

Health education tool

1. Blindness Daisy Dharmaraj MD Dpt of Community Medicine ACS Medical college

2. WHO definition Partial Blindness : Visual acuity of less than 3/60 ( Snellen ) or its equivalent ( inabilty to count fingers in daylight at a distance of 3 meters) Total blindness

3. Indian scenario Source:  Vision 2020 India.org CAUSE FOR BLINDNESS PERCENTAGE OF CONTRIBUTION Cataract 62.6% Refraction Error 19.7% Glaucoma 5.8% Corneal pathologies 0.9% Other Causes 11.00%

4. The commonest causes of visual impairment are uncorrected refractive errors, cataract and glaucoma . Age related mac ular degeneration.

5. Epidemiological determinants Age Malnutrition Occupation Awareness Access to healthcare

6. Prevention of avoidable blindness Nutrition Treatment Control infections Improving safety conditions

7. Proper waste disposal Street waste –leaves, paper, straw, animal dropping Market waste –putrid veg and animal matter Stable litter –animal droppings and animal feeds Domestic waste - ash, rubbish, garbage Personal Hygiene Wash hands often Daily baths Treatment of people with eye infections Eye hygiene

8. Eye injuries Eye can be injured by sharp objects or chemicals. This happens usually in factories or homes. The eye gets inflamed and the other eye can also show a similar reaction

9. Prevention and treatment Protective equipment has to be used if injuries are anticipated. The injured person has to be immediately examined by the eye doctor to see the extent of injury. The foreign body has to be removed. Inflammation has to be treated carefully. The person has to be under medical care till s/he is absolutely safe.

10. Eye injuries

11. Cataract

12. Cataract the lens of the eye becomes thick and less transparent. This means that the rays of light defining the object cannot pass through the lens as before. Thus eyesight becomes dim. As the lens thickens further it can burst and cause permanent damage to the eye. The lens can easily be removed by surgery. An artificial lens is inserted, which restores the sight. As they don’t know about cataract or because they cannot get medical services, thousands become blind due to cataract

13. Glaucoma There is constant flow of fluid in the eyes. The fluid is secreted by glands and removed through a duct. If there is any obstruction to this flow, the pressure in the eye increases. This is the commonest type of glaucoma. This causes headache, haloes around object, hazy vision, sudden loss of vision, nausea or vomiting. It can cause permanent damage to the nerves of the eyes . The condition can arise suddenly or over the years .(acute/ chronic)

14. Prevention and treatment If these symptoms are experienced you need to consult an ophthalmologist. If you are above 50, check your eyes annually . If discovered early, glaucoma can be treated by medicines and/ or surgery.

15. Refractive errors Visi on is affected if the curvature of the lens in the eye changes SHORT SIGHT – you can clearly see only nearby objects. As distance increases your vision is blurred. LONG SIGHT- you can clearly see only distant objects. As distance decreases your vision is blurred. ASTIGMATISM .- Though you can see near and far, the images are blurred

16. Correcting Refractive errors These can be corrected by testing your eyes at an eye clinic and wearing appropriate glasses

17. Components for action Primary eye care- acute conjunctivitis , trachoma,, superficial foreign bodies, xerophthalmia )- Promotion of personal hygiene, Sanitation etc Secondary care – management of common blinding conditions such as cataract, trichiasis , entropion , ocular trauma, glaucoma etc (PHC, district hospitals, mobile eye clinics) Tertiary care -retinal detachment surgery, corneal grafting,, eye banks,, rehabilitation of the blind (In medical colleges and institutes of medicine-)

18. Other causes of blindness are Vit A deficiency Measles Onchocerciasis -parasitic Severe Conjunctivitis Tumours and other diseases of the eye

19. THANK YOU