BLINDNESS
By
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 Maximum less than Minimum equal to or
impairment better than
Low Vision 1. 6/18 6/60
2. 6/60 3/60
Blindness 3. 3/60(FC at 3 mts) 1/60 (FC at 1 mt)
4. 1/60 (FC at 1 mt) Light Perception
5. No 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
Developed Countries
Most frequent causes of blindness:
Accidents>Glaucoma>Diabetes>Vasc
ular 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
Other causes includes:
Congenital disorders
Uveitis
Retinal detachment
Tumors
Diabetes
Hypertension
Diseases of the Nervous system
Leprosy
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.
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 signs
X1A: Conjunctival xerosis
X1B: Bitot‟s Spots
X2: Corneal xerosis
X3A: Corneal ulceration
X3B: Keratomalacia
Secondary signs:
XN: Night Blindness
XF: Fundal changes
XS: 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.
TERTIARY
SECONDARY
PRIMARY
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!