BLINDNESSBy

Dr. Abantika Bhattacharya

3rd Yr Post-Graduate Trainee

M.D. Community Medicine

Burdwan Medical College

The WHO defines blindness as visual acuity of less than 3/60 (inability to count fingers at a distance of 3 metres), or corresponding visual field loss, in the better eye with best possible correction.

Uniocular blindness is not blindness because the other eye is normal.

Low Vision corresponds to visual acuity of less than 6/18, but equal to or better than 3/60, in the better eye with best possible correction.

Definition: WHO ICD -10 The defining criteria for visual impairment and blindness as per WHO (ICD - 10)

Categories of visual impairment

Maximum less than Minimum equal to or better than

Low Vision 1. 6/18

2. 6/60

6/60

3/60

Blindness 3. 3/60(FC at 3 mts)

4. 1/60 (FC at 1 mt)

5. No Light Perception

1/60 (FC at 1 mt)

Light Perception

If the patient reads 6/18 or better, he is coded 0, that is no visual impairment.

Indian Definition Visual acuity of less than 6/60 with usual

spectacle correction (presenting visual acuity), or visual field equal to or less than 20 degree in the better eye (ICMR, WHO,NPCB).

Also known as Economic blindness. Presenting visual acuity rather than best

corrected vision was used since many people in developing countries like India, do not have appropriate, if any, refractive correction.

Other Categories of Blindness

Preventable blindness: Which could have been completely prevented by effective measures, such as blindness due to Vit A deficiency, measles, ophthalmia neonatorum, and injuries.

Curable blindness: That which is reversed by prompt management eg. Blindness due to cataract.

Avoidable blindness: The sum total of Preventable and Curable blindness. In India, 85-90% of blindness is avoidable.

Economic Blindness: Visual acuity of less than 6/60 with usual spectacle correction or visual field equal to or less than 20° in the better eye.

Problem statement: World.

180 million people worldwide are visually disabled.

45 million are blind (4 out of 5 live in developing countries).

80% of this blindness is avoidable. 1/3rd of the world’s blind live in SEAR

countries. 50% of the world’s blind children live in

the SEAR.

Diagram 1:Bar Diagram Showing Causes of Blindness in the World in Million

Cataract, 19

Glaucoma, 6.4Trachoma, 5.6

CB, 1.5Onchocer, 0.29

Others, 10

0

2

4

6

8

10

12

14

16

18

20

Cataract Trachoma Onchocer

Developed Countries

Most frequent causes of blindness: Accidents>Glaucoma>Diabetes>Vascular disease (hypertension) > Cataract > Degeneration of ocular tissues (retina) > Hereditary conditions.

Cataract

Vision with a cataract

Problem Statement-India Prevalence of blindness-0.7% (2000).

No. of blind persons-6,800,000

Main causes of blindness- cataract, Refractive error, Childhood blindness, Corneal blindness.

Very high prevalence states (>=2%) : Jammu & Kashmir, Madhya Pradesh and Rajasthan.

Low prevalence states( <1%) : Delhi, Himachal Pradesh, North Eastern states, Punjab, West Bengal.

Prevalence is higher among those above 50 years, females, poor and illiterate, those living in under deserved rural and tribal areas, farmers and labourers.

Inaccessibility to eye care services or not availing of services is the major reason for high prevalence of blindness.

Diagram 2: Pie chart showing major causes of blindness in India

62%20%

6%5% 1% 6%

Cataract

RE

Glaucoma

PSP

Corneal

Others

Other causes includes: Congenital disorders Uveitis Retinal detachment

TumorsDiabetesHypertension Diseases of the Nervous systemLeprosy

Arteriolar Narrowing: in hypertensive retinopathy

Social aspects of the problem:

Some common reasons for not availing surgical services for cataract:

Waiting for maturity No one to accompany Fatalistic attitude due to very old age Fear of operation/complications Economic reasons Lack of information.

Epidemiological Determinants:

1. Age : 82% of the blind people are aged

above 50 years, childhood visual impairment represents 4 to 5 % of all visual impairment.

2. Sex: 1.5 to 2.2 women for 1 male. The main reason is reduced access of women to eye care services.

3. Diabetes : Retinopathy, cataract.

4. Tobacco smoking : Macular degeneration and cataract.

5. Occupation : Eye injuries, as in welders, agriculturists, soldiers.

6. Cultural factors : Festivals.

7. Poor Socio-Economic Status.

8. Genetic factors : Retinitis Pigmentosa.

9. HIV Infection and the eye : Microangiopathy,anterior segmental manifestations as molluscum contagiosum and kaposi’s sarcoma; or,posterior segmental opportunistic infections, mainly Cytomegalovirus causing CMV retinitis.

Changing Concepts in Eye Health care Primary eye care:

Promotion and protection of eye health, on spot treatment for commonest eye diseases like acute conjunctivitis, opththalmia neonatorum, trachoma, superficial foreign bodies, xerophthalmia.

VHG, MPHW, Link workers involved. Provided with essential drugs. Referral –corneal ulcer, penetrating foreign bodies,

painful eye conditions, infections. Health education. Final objective –to increase coverage and quality of eye

health care through primary health care approach.

Epidemiological approach Studies at the population level Measurement of incidence, prevalence of

diseases and their risk factors.

Team concept Use of auxiliary health personnel to fill the

‘gaps’. Recruitment of village health guides, ophthalmic

assistants, multi-purpose workers and voluntary agencies.

Establishment of national programmes Prevention of blindness from all causes Goal: to reduce blindness in the country to

0.3% by the year 2000.

Prevention of Blindness

Initial Assessment Methods of Intervention Long Term Measures Evaluation

Primary eye care Secondary care Tertiary care Specific programmes

Trachoma Control

School eye healh services

Vit A prophylaxis

Occupational eye health services

Primary Eye Care : Health Education. Upliftment of socio - economic status, general

standards of living and general education. Nutritional supplementation programmes,

especially with vitamin A, Immunization. Provision of eye care services. Personal protection : personal protection using

goggles / eye shields in high risk occupations should be ensured.

Social actions during fairs and festivals.

Secondary Eye Care : Early diagnosis and treatment: definitive

management of common blinding conditions. Cataract, glaucoma, trachoma, refractive errors

and diabetic eye complications and providing early emergency treatment for injuries.

PHC, District Hospitals, Eye camp approach. Health Examinations: Combine eye health. Special Screening Examinations : Retinopathy of

Prematurity (ROP) and Retinitis Pigmentosa (RP).

o Cataract : Surgical removal of the opacified lens followed by intraocular lens implantation or else provision of spectacles is the only way of tackling cataract.

o Trachoma : The “SAFE” strategy (Surgery, Antibiotics to control infection, Facial cleanliness and Environmental improvements) has been recommended by the WHO.

Blinding Trachoma

SAFE-TRACHOMA

o Glaucoma : Early diagnosis and treatment should be addressed at the PHC level and referral to the District ophthalmologist /apex ophthalmic institutes if required.

o Diabetic Eye Complications : Early detection of diabetes, including detailed ophthalmologic assessment of diabetics, education regarding eye care, control of blood sugar levels and warning signs of diabetic eye complications.

o Refractive Errors : Optometrists working at the block primary health care level should be equipped to undertake refraction and provide glasses

School eye health

Tertiary Eye Care : Medical Colleges, Apex Institutes. Retinal Detachment surgery, corneal

grafting Disability Limitation: Sonic torches

and trained dogs. Rehabilitation : School for blind, Braille

script.

National and International Agencies for

Blindness The National Association for the Blind

(NAB) The Royal Commonwealth Society for

the Blind International Agency for Prevention of

Blindness The WHO

National Programme for Control of

Blindness Launched in 1976 Goal: to reduce the prevalence of

blindness from 1.4% to 0.3% As per 2006-2007 survey, the

prevalence of blindness was 1%.

Revised Strategies

To make NPCB more comprehensive by strengthening services for other causes of blindness like corneal blindness, refractive errors in school going children, improving follow-up services of cataract operated persons and glaucoma.

To shift from eye camp approach to fixed facility surgical approach and from non-conventional surgery to IOL implantation for better quality post-operative vision in operated patients.

To expand the world bank project activities like construction of dedicated eye operation theatres, eye wards at district level, training of eye surgeons in modern cataract surgery and other eye surgeries and supply of ophthalmic equipments.

To strengthen participation of Voluntary Organizations in the programme and to ear-mark geographic areas to NGOs and Government Hospitals to avoid duplication of effort and to improve performance.

To enhance the coverage of eye care services in tribal and other under-served areas through identification of bilateral blind patients, preparation of village-wise blind register and giving preference to bilateral blind patients for cataract surgery.

Objectives of the Programme To reduce the backlog of blindness of

blindness through identification and treatment of blind

To develop comprehensive eye care facilities in every district

To develop human resources for providing eye care services

To improve quality of service delivery To secure participation of Voluntary

Organizations in eye care.

Infrastructure Development For Eye Care

Strengthening of PHCs Central Mobile Units Strengthening of District Hospitals Upgrading Departments of Ophthalmology in Medical

Colleges Establishment of Regional Institutes Ophthalmic Assistant Training Centres District Mobile Units State Ophthalmic Cells DBCS Eye Banks Paramedical Ophthalmic Assistants posted

School Eye Screening Programme 6-7% of children aged 10-14 years have problem

with their eye sight affecting learning at school Children are first screened by trained teachers:

RE, amblyopia, squint, trachoma etc. Children suspected to have refractive error are

seen by ophthalmic assistants and corrective spectacles are prescribed or given free for persons below poverty line.

Taught: principles of good posture, proper lighting, avoid glare, proper distance and angle between books and eyes.

Collection and Utilization of Donated Eyes

Hospital retrieval programme is the major strategy for the collection of donated eyes.

Eye donation fortnight is organized from 25th August to 8th September every year to promote eye donation/eye banking.

New Initiatives Proposed under the Programme

Construction of dedicated eye wards and eye operation theatres in district and sub-district hospitals in north-eastern states, Bihar, Jharkhand, J & K, Himachal Pradesh, Uttaranchal.

Appointment of ophthalmic surgeons and ophthalmic assistants in new districts in district hospitals and sub district hospital

Appointment of ophthalmic assistants in PHC s/ Vision Centres where there are none

Appointment of eye donation counsellors on contract basis.

Grant –in-aid for NGOs for management of other eye diseases other eye diseases other than cataract, like diabetic retinopathy, glaucoma management , laser technique, corneal transplantation, vitreo-retinal surgery, treatment of childhood blindness.

Special attention to clear cataract backlog and take care of other eye health care centres from NE states

Telemedicine in Ophthalmology Involvement of Private Practitioners Provision of 1550 crore has been

proposed for implementation of NPCB during the 11th Five year plan

Vit A supplementation and MMR vaccination through DBCS funds to take care of childhood blindness

Setting up of 5 centres for excellence for eye care services

Vit A Prophylaxis

At 9 months : 1 Lakh IU along with Measles vaccine

At 18 months: 2 Lakh IU along with OPV/ DPT Booster

Subequently every 6 months till 5 years of age

Total 9 Doses. Breast-fed babies do not need Vit A

supplement in the first 6 months.

Xerophthalmia Primary signsX1A: Conjunctival xerosisX1B: Bitot’s SpotsX2: Corneal xerosisX3A: Corneal ulcerationX3B: Keratomalacia Secondary signs:XN: Night BlindnessXF: Fundal changesXS: Corneal scarring

Bitot’s Spot

Xerophthalmia

Vision 2020: The Right To Sight Global initiative to reduce avoidable

(preventable and curable) blindness by the year 2020 and reduce prevalence of blindness in India to 0.5% by 2012.

Established on 18th Feb, 1999 by WHO. Launched in India on 14th October 2004. Concept- centred around ‘right’ issues:

“Recognition of sight is a fundamental human right”.

Target diseases: cataract, refractive errors, childhood blindness, corneal blindness, glaucoma, diabetic retinopathy.

Strategies: Human resource development, infrastructure and technology development at various levels of health system.

CENTRE FOR EXCELLENCE 20Professional leadershipStrategy development

CMETRAINING CENTRES 200

Retinal surgery,Corneal transplantGlaucoma surgery

Training

SERVICE CENTRES 2000•Cataract Surgery

•Other common eye surgeries•Facilities for refraction

•Referral services

VISION CENTRES 20,000• Refrraction and prescription of glasses

•Primary eye care•School eye screening programme

•Screening and referral services

PRIMARY

SECONDARY

TERTIARY

By the year 2020, 100 million people are to be saved from going blind.

“Restoration of sight and blindness prevention strategies” : most cost effective intervention in health care.

“World Sight Day” is observed on 2nd Thursday of October every year to raise public awarness of blindness, to influence Governments to designate funds for blindness prevention programmes and to educate target audiences about blindness prevention.

THANK YOU!

THANK YOU!