Blindness

Blindness

1. Blindness Nilufa Akter Optometrist ( B.Optom , ICO,CMU) Ispahani Islamia Eye Institute and Hospital

2. Low Vision (WHO definition) “A person with low vision is one who has impairment of visual functioning even after treatment and/or standard refractive correction, and has a visual acuity of less than 6/18 to light perception, or a visual field less than 10 degrees from the point of fixation, but who uses, or is potentially able to use, vision for the planning and/or execution of a task.”

3. Blindness WHO definition of blindness -the best corrected visual acuity in the better eye less than 3/60 and/or visual field less than 10 degree from the point of fixation.

4. 2 main categories of blindness Partial blindness : - have very limited vision 2. Complete blindness: - can not see anything and do not see light

5. Types of Blindness 1. Economic blindness 2.Social blindness 3. Manifest blindness 4. Absolute blindness 5. Curable blindness 6. Preventable blindness 7. Avoidable blindness

6. 1. Economic blindness:  Inability of a person to count fingers from a distance of 6 meters or 20 feet 2. Social blindness:  Vision 3/60 or diminution of field of vision to 10° 3. Manifest blindness:   Vision 1/60 to just perception of light 4. Absolute blindness:  No perception of light 5. Curable blindness:   That stage of blindness where the damage is reversible by prompt management e.g. cataract

7. 6 . Preventable blindness:  The loss of blindness that could have been completely prevented by institution of effective preventive or prophylactic measures e.g. xerophthalmia , trachoma and glaucoma 7. Avoidable blindness:  The sum total of preventable or curable blindness is often referred to as avoidable blindness.

8. Magnitude of the problem Global : - It is estimated that 180 million people are visually impaired of them 45 million people are blind India: - The prevalence of blindness is 77% and 68 lakh people are blind as per W.H.O. statistics.

9. Causes of Blindness 1. Congenital/ Developmental defect (Leading causes of childhood blindness) - Xerophthalmia , congenital cataract, congenital glaucoma & optic atrophy 2. The leading causes are- - DM, Glaucoma, vascular disease, Macular degeneration, and accident (such as chemical burns or sports injury) 3. Worldwide leading causes of blindness are- -cataract, trachoma, leprosy and vit -A deficiency. 4. Other causes include:- - Blocked blood vessels, complication of premature birth ( Retrolental fibroplasia ), complication of eye surgery

10. INDIA 2001-02 National survey on blindness Main causes of blindness are as follows: 1. Cataract 62.6% 2. Uncorrected Refractive error 19.7% 3. Glaucoma 5.8% 4. Posterior segment pathology 4.7% 5. Corneal blindness 0.9% 6. Other causes 6.2% 7. Surgical complication 1.2% 8. Estimated National Prevalence of childhood Blindness/ Low Vision is 0.80 per thousand.

11. Epidemiological determinants 1 . Age: – I n children & young : Refractive error, trachoma, conjunctivitis, malnutrition. – In adults : cataract, refractive error, glaucoma, DM 2. Sex: – Higher prevalence of trachoma, conjunctivitis and cataract in women leading to higher prevalence of blindness in women

12. 3. Malnutrition : – Infectious diseases of childhood especially measles & diarrhoea – PEM – Severe blinding corneal destruction due to vit . A deficiency in first 4 to 6 years of life. 4. Occupation : – People working in factories, workshop, industries are prone to eye injuries because of exposure to dust, airborne particles, flying objects, gases, fumes, radiation.

13. 5. Social class : – Surveys indicate that blindness twice more prevalent in poorer classes than in the well to do. 6. Social factors : – Basic social factors are ignorance, poverty, low standards of personal and community hygiene and inadequate health care services.

14. Prevention of Blindness The components for action in national programmes for the prevention of blindness comprise the following : Initial assessment Methods of intervention – primary eye care – secondary care – tertiary care – specific programmes Long term measures

15. Initial assessment – Assess the magnitude, geographic distribution, and causes of blindness within the country by prevalence survey.

16. Methods of Intervention Primary eye care – Wide range of eye conditions can be treated or prevented at grass root level by locally trained health workers who are first to make contact with the community. – They are also trained to refer the difficult cases to the nearest PHC or district hospital. – Their activities also involve promotion of personal hygiene, sanitation, good dietary habits and safety in general.

17. Secondary care: – Involves definitive management of common blinding conditions as cataract, trichiasis , entropion , ocular trauma, glaucoma. – It is provided in PHCs and district hospitals where eye depts are established. – May involve the use of mobile eye clinics

18. Tertiary care – Established in the national or regional capitals and are often associated with medical colleges and institutes of medicine. – Provide sophisticated eye care such as retinal detachment surgery, corneal grafting which are not available in the secondary centres . – Other measures of rehabilitation comprise education of blind in the special schools & utilisation of their services in the gainful employment.

19. Specific programmes – Trachoma control – School eye health services: Screening and treatment , Health education – Vit.A prophylaxis – Occupational eye health services

20. Long term measure – Aimed at improving quality of life – Modifying or attacking the factors responsible for the persistence of eye health problems. • Poor sanitation • Lack of adequate safe water supply • Poor nutrition • Lack of personal hygiene

21. National Programme for Control of Blindness (NPCB) • Was launched in the year 1976 as a 100 % centrally sponsored programme • It incorporates the earlier trachoma control programme started in the year 1968 • Goal: To reduce the prevalence of blindness from 1.4 to 0.3% by 2020. • In the year 2006-07: prevalence was 1.0%

22. Strategy of Programme Strengthening eye care service delivery Developing human resource for eye care Promoting out-reach activities & public awareness Developing institutional capacity Increase and expand research Participation of NGOs

23. School Eye Screening Programme 6-7 % children age to 10-14 years – Eye sight problem Children – screened by school teachers. Suspected refractive error are seen by ophthalmic assistants & spectacles are prescribed free of cost.

24. Vision 2020: The Right to Sight -Is the Global initiative to reduce avoidable (Preventable and curable) blindness by the year 2020. -It was launched in 1999 and a joint programme of WHO and IAPB(International Agency for the Prevention of blindness). Main features: – Target Diseases – Human resource development and infrastructure and technology development.

25. Proposed Structure for VISION 2020: THE RIGHT TO SIGHT

26. Management of Blindness 1. The treatment of blindness depends on the cause of blindness. 2. Blindness due to nutritional deficiency:  It can be addressed by dietary changes. 3. Visual impairment due to refractive error : It can be addressed by doing a refraction and providing appropriate spectacles. 4. Inflammatory and infectious causes of blindness  can be treated with medication in the form of drops or pills. 5. Most of people are blind due to cataract:  In these patients, cataract surgery would, in most cases, restore their sight.