A brief overview of prevention of blindness

2. Dr. Mahnoor
Department of Community Medicine
Watim medical college

3. • A 6-year-old child presents with night blindness. What could be the
cause?

4. Learning Objectives
• By the end of this session, students should be able to:
• Define blindness and its global and national burden.
• Identify risk factors and causes of blindness.
• Explain prevention strategies based on the epidemiological model.
• Discuss the role of WHO & national programs in blindness prevention.
• Apply prevention strategies in community settings

5. • What are the main causes of blindness?
• How does Vitamin A deficiency affect vision?
• What is the role of public health in preventing blindness?

7. Epidemiology of Blindness
• WHO defines blindness as visual acuity of
3/60 or its equivalent.
• In the absence of a vision chart it is the
inability to count fingers in daylight at 3
meters distance.

Prevalence in Pakistan:
85.4% of blindness is avoidable in
Pakistan. Most common causes are
untreated cataract and refractive
errors.

9. Causes and risk factors
• In developed countries:
• Accidents, glaucoma, DM, vascular disease, cataract and ocular
degeneration of ocular tissue.
• Leading causes of childhood blindness.
• Xerophthalmia, congenital cataract, congenital glaucoma and optic
atrophy.

10. Causes of Preventable blindness

Uncorrected refractive errors

Untreated cataract

Glaucoma

Xerophthalmia due to (Vit A deficiency): Signs and symptoms on eye
examination: Night blindness, dry eyes (xerosis), bitot spot, keratomalacia,
corneal ulcers (keratitis). Easily treated with vitamin A supplementation.

Trachoma: Caused by chlamydia trachomatis. Trachoma is contagious,
spreading through contact with the secretions of eyes, eyelids, and
nose/throat secretions of infected people. Spreads in communities due to
poor hygiene.
Signs and symptoms:Follicular conjunctivitis which scars and tightens eyelids
which causes inward-turning of eyelashes (trichiasis) leading to corneal ulcer
(keratitis). Treated with antibiotics.

11. 
Ocular trauma

Hereditary conditions such as retinoblstoma

Retinopathy of prematurity

Congenital cataract

Congenital glaucoma

Corneal ulcers

Diabetic retinopathy

Hypertensive retinopathy

12. Bitot spots (xerophthalmia)
Corneal ulcer
Punctate keratitis seen in
measels
Hazy cornea seen in
xerophthalmia
cataract
retinoblastoma

13. Trichiasis; a complication of
trachoma
Trauma leading to exposure keratitis
Follicular conjunctivitis

14. Epidemiological determinants
• Age:
• In children & young: Refractive errors, trachoma, conjunctivitis, malnutrition.
• In adults: Cataract, refractive error, glaucoma, DM
• Sex:
• Higher prevalence of trachoma, cataract and conjunctivitis in women leading to higher
prevalence of blindness in women.
• Malnutrition:
• Infectious diseases of childhood especially measles and diarrhea.
• PEM
• Corneal destruction due to vitamin A deficiency.
• Occupation:
• People working in factories, workshops, industries are prone to eye injuries because of exposure
to dust, airborne particles, flying objects, gases, fumes and radiation.

15. PREVENTION

PRIMARY EYE CARE: wide range of eye conditions such as xerophthalmia, conjunctivitis,
trachoma, foreign bodies, etc can be treated at the grass-root level by locally trained
primary health worker who are first to make contact with the community. They are also
trained to refer complex cases to nearest PHC or district hospital.

SECONDARY CARE: this care is provided in PHCs and district hospitals and involves
definitive management of cataracts, glaucoma, ocular trauma, trichiasis etc. Early detection
through screening programms for e.g school eye health screening and Mobile eye camps.

TERTIARY CARE:services established is national or regional capitals. Specialized tertiary
care teaching hospitals/ institutes. They provide sophisticated eye surgery I.e corneal
grafting, retinal detachment surgery.
• Other measures of rehabilitation comprise education of blind in special schools, provision of
gainful employment.

16. PREVENTION

SPECIFIC PROGRAMMES:
Trachoma control
school eye health services
vitamin A prophylaxis
EPI
Occupational eye health services

LONG TERM MEASURES: these measures are aimed to attack factors
responsible for persistence of eye health problems e.g poor sanitation, lack of
safe water supplies, little intake of foods rich in vit A, lack of personal hygiene.
Health education is important long term measure to create community
awareness, motivation and participation.

17. Vision 2020
• "Vision 2020:
• The Right to Sight" was a global initiative launched by the World
Health Organization (WHO) and the International Agency for the
Prevention of Blindness (IAPB) with the goal of eliminating avoidable
blindness worldwide by the year 2020, focusing on preventing major
causes like cataracts, trachoma, and refractive errors, essentially
advocating for everyone's right to sight.

19. National program for prevention and control of
blindness
• The National Program for Prevention and Control of Blindness (NPPCB) is a program in
Pakistan that aims to reduce blindness and visual impairment. The program includes activities
such as improving eye care services, training eye care personnel, and raising awareness.
• Goals
• Improve access to eye care
• Improve the quality of eye care services
• Develop low-vision services
• Train eye care personnel
• Raise awareness about eye health
• Conduct research
• Develop community programs

20. • Program activities
• Upgrading eye departments in hospitals
• Developing outreach programs
• Developing new low-vision clinics
• Training teachers and instructors in orientation and mobility
• Developing a referral chain from communities to First Level Care Facilities (FLCFs)
• Integrating eye health indicators into monthly reporting tools
• Support
• The NPPCB receives support from international organizations such as Sightsavers. These organizations help
with training, capacity building, and developing referral chains.
• Success
• Pakistan has eliminated blinding trachoma, which is a significant public health victory.

21. • Case 1: A middle-aged man develops progressive vision loss due to
cataracts. What prevention strategies apply?
• Case 2: A child in a low-income community has night blindness. How can
we intervene?

22. • Take-Home Message: 80% of
blindness is preventable.
Prevention starts with awareness.
• Call to Action: Promote school-
based vision screening & eye care
awareness.