Download - Epidemiology of blindness
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4BY :BRIG DR HEMANT KUMAR
BLINDNESS
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1. 285 million people are estimated to be visually impaired ,246 have low vision while 39 million are blind worldwide.
2. About 90% of the world's visually impaired live in low-income settings.
3. 82% of people living with blindness are aged 50 and above.
4. 80% of all visual impairment can be prevented or cured.
KEY FACTS
Fact Sheet N°282 WHO- August 2014
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• With 7.8 million blind people in India, while 45 million are visually challenged. the country accounts for 20 per cent of the 39 million blind population across the globe.
• It is estimated that prevalence of Childhood blindness in India is 0.8/1000 children in <16 years age group, implying a total of 300,000 blind children in our country.
INDIA
http://www.deccanherald.com/content/240119/india-accounts-20-per-cent.html
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Out of these 62 per cent are on account of cataract, 19.7 per cent refractive error, 5.8 per cent glaucoma and one per cent corneal blindness
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There are 4 levels of visual function, according to the International Classification of Diseases -10 (Update and Revision 2006):
NORMAL VISION MODERATE VISUAL IMPAIRMENT SEVERE VISUAL IMPAIRMENT BLINDNESS.
DEFINITIONS
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Visual acuity is usually measured with a Snellen chart. The Snellen chart displays letters of progressively smaller size. "Normal" vision is 20/20.
This means that the test subject sees the same line of letters at 20 feet that a normal person sees at 20 feet.
NORMAL VISION
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Visual impairment is defined as the limitation of actions and functions of the visual system.
The National Eye Institute defines low vision as “a visual impairment not correctable by standard glasses, contact lenses, medication or surgery that interferes with the ability to perform activities of daily living”
DEFINITION OF VISUAL IMPAIRMENT
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WHO Definition:- Visual Acuity less than 3/60 (Snellens)or its
equivalent. • NPCB Definition:- Inability of a person to count fingers from a
distance of 6 meters or 20 feet. – Vision 6/60 or less with the best possible spectacle correction – Diminution of field vision to 20 degrees or less in better eye
DEFINITION OF BLINDNESS
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1.Economic Blindness 2.Social Blindness 3.Manifest Blindness 4.Absolute Blindness 5.Curable Blindness 6.Preventable Blindness 7.Avoidable Blindness
TYPES OF BLINDNESS
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Visual Acuity:- Sharpness of vision, measured as
maximum distance a person can see a certain object, divided by the maximum distance at which a person with normal sight can see the same object •
Economic blindness:- – Inability of a
person to count fingers from a distance of 6 meters or 20 feet.
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Social blindness:- – Vision 3/60 or diminution of field of vision to 10 degrees
Manifest blindness:- – Vision 1/60 to just perception of light.
Absolute blindness:- – No perception of light
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Curable blindness:- – That stage of blindness where the damage is reversible by prompt management e.g. cataract •
Preventable blindness:- – The loss of vision that could have been completely prevented by institution of effective preventive or prophylactic measures.
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Is a level of vision loss that has been legally defined to determine eligibility for benefits.
The clinical diagnosis refers to a central visual acuity of 20/200 or less in the better eye with the best possible correction, and/or a visual field of 20 degrees or less
LEGAL BLINDNESS
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GLOBAL Cataract , glaucoma, DM, vascular disease,
accidents & degeneration of ocular tissue Leading causes of childhood blindness Xerophthalmia, congenital cataract,
congenital cataract, congenital glaucoma & optic atrophy.
CAUSES OF BLINDNESS
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INDIAMain causes of blindness are as follows: 1. Cataract (62.6%) 2. Refractive Error (19.70%) 3. Corneal Blindness (0.90%), 4. Glaucoma (5.80%),5. Surgical Complication (1.20%)6. Posterior Capsular Opacification (0.90%)7. Posterior Segment Disorder (4.70%), 8. Others (4.19%) 9. Estimated National Prevalence of Childhood Blindness
/Low Vision is 0.80 per thousand
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Age:◦In children & young: Refractive error,
trachoma, conjunctivitis, malnutrition.
◦In adults: cataract, refractive error, glaucoma, DM
Sex:◦Higher prevalence of trachoma, conjunctivitis
and cataract in women leading to higher prevalence of blindness in women
EPIDEMIOLOGICAL DETERMINANTS
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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. Occupation:
◦People working in factories, workshop, industries are prone to eye injuries because of exposure to dust, airborne particles, flying objects, gases, fumes, radiation.
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Social class:◦Surveys indicate that blindness twice
more prevalent in poorer classes than in the well to do.
Social factors:◦Basic social factors are ignorance,
poverty, low standards of personal and community hygiene and inadequate health care services.
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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
Long term measures
PREVENTION OF BLINDNESS
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Primary careWide 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.
METHODS OF INTERVENTION
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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
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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.
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SPECIFIC PROGRAMMES◦Trachoma control◦School eye health services: Screening and treatment , Health education
◦Vit. A prophylaxis◦Occupational eye health services
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Aimed at improving quality of life and modifying the factors responsible for eye problems.
Poor sanitationLack of adequate safe water supplyPoor nutritionLack of personal hygiene
LONG TERM MEASURES
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1. Was launched in the year 1976 as a 100% Centrally Sponsored scheme with the goal to reduce the prevalence of blindness from 1.4% to 0.3%.
2. Survey conducted during 2006-07 showed reduction in the prevalence of blindness from 1.1% (2001-02) to 1% (2006-07).
3. Now the target is to achieving the goal of 0.3% by the year 2020.
NATIONAL PROGRAMME FOR CONTROL OF BLINDNESS
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The four pronged strategy of theprogramme is:
strengthening eye care service delivery, developing human resources for eye care, promoting outreach activities and public awareness . developing institutional capacity. Increase and expand research.Participation of NGOs
STRATEGY OF PROGRAMME:
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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.
SCHOOL EYE SCREENING PROGRAMME
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VISION 2020: The Right to Sight is the global initiative for the elimination of avoidable blindness, a joint programme of the World Health Organization (WHO) and the International Agency for the Prevention of Blindness (IAPB).It was launched in 1999 to promote:
“A world in which nobody is needlessly visually impaired, where those with unavoidable vision loss can achieve their full potential.”
Contd..
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The Global Initiative aims to: “Intensify and accelerate prevention of blindness
activities so as to achieve the goal of eliminating avoidable blindness by 2020.”
It sought to do this by: focusing on certain diseases which are the main
causes of blindness and for which proven cost effective interventions are available.”
Contd..
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“Universal Eye Health: A global action plan 2014 – 2019" (GAP) was unanimously adopted by Member States at the World Health Assembly in 2013 as part of WHA resolution
The Vision of the GAP is:
“A world in which nobody is needlessly visually impaired, where those with unavoidable vision loss can achieve their full potential and where there is universal access to comprehensive eye care services.”
Global Action Plan 2014-2019
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1. Reduce Visual Impairment as a global public health problem
2. Secure access to rehabilitation for visually impaired services
The Objectives of the GAP are to:
3. Develop and implement integrated national eye health policies and plans;
4. Ensure multi-sectoral engagement and effective partnerships
The Goal of the GAP
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