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Corneal blindness in a southern Indian populationDr. Meenank. B
M.S. Ophthalmology (Post-Graduate )
ASRAM Medical College
Introduction Blindness : Presenting distant visual acuity of < 6/ 60 (or) central vision < 20˚ in the better eye ( NPCB)
categories of visual impairment as per WHO (1977)
Category of visual impairment
Level of visual acuity (Snellen)
Normal vision Category 0
6/6 to 6/18
Low vision category 1
6/18 to 6/60
category 2
6/60 to 3/60
Blindness Category 3
3/60 to 1/60 (or) V.F 5˚ and 10˚
Category 4
1/60 to PL⁺ (or) V.F less than 5˚
Category 5
NPL
Major Causes of Blindness in India
Disease
Rapid Assessment of Avoidable Blindness(RAAB) 2006 -07’
National Program for Control of Blindness( NPCB ) 2001 -02 ‘
Cataract 72.2% 62.6%
Refractive errors 6.3% 19.7%
Glaucoma 4.4% 5.8%
Complications of cataract surgery
3.0% 1.0%
Corneal opacities including trachoma
6.5% 0.9%
Corneal Blindness Visual impairment and gross degree of visual loss occurring due to disease of cornea
India – 25,000 to 30,000 / yr
Major causes of corneal blindness Corneal Ulcers Trachoma Ocular injuries Keratomalacia
Corneal blindness in a southern Indian population: need for health promotion strategies
R Dandona1,2 and L Dandona1
1Centre for Social Services, Administrative Staff College of India, Hyderabad, India and International Centre for Advancement of Rural Eye Care, LV Prasad Eye Institute, Hyderabad, India
2Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
Journal – The British Journal of Ophthalmology (BJO) Type – Peer review journal Publisher – BMJ Publishing Group (United Kingdom) ISSN no. – 0007-1161, 1468-2079 Impact factor – 2.725 Year, issue, volume, and page no. - 2003 February; 87(2): 133–141. PubMed PMID: 12543736 PubMed Central PMCID: PMC1771511
Dr Rakhi Dandona
Aim – To assess the distribution and cause of corneal blindness in a population in southern India
Andhra Pradesh Eye Disease Study ( APEDS) states A.P population – 76 million (2001) rural 73% Age distribution 15yrs and below – 35.6% 16yrs to 29yrs – 25.7% 30 and above – 38.7% objectives of APEDS to determine the prevalence and causes of blindness and visual impairment to determine the risk factors associated with major eye diseases to determine the barriers to eye care services to determine the quality of life in the visually impaired prevalence of blind people in A.P -1.84%, of which 7% was due to
corneal diseases
Methods
Prevalence of corneal blindness Participated – 10,293 Both eyes – 13 One eye – 73
Prevalence in four areas of APEDS combined and adjusted for age, sex, and urban/ rural – 0.66%
95% CI – 0.49 to 0.86 Design effect – 1.35
Causes of corneal blindness
prevalence of corneal blindness in all 4 areas of APEDS irrespective of age, sex, socio-economic status
Causes of corneal blindness in all 4 areas of APEDS
22 of 86 participants had trauma at-least in one eye
Factors Urban Rural
Percentage
5(31.8%) 15 ( 68.2%)
Age <15yr (71.4%)
>15yrs (73.3%)
cause Flying/ thrown objects
Veg. matter
Incidence
42.9% @ playing
46.7% @ working
sex and urban-rural distributionadjusted prevalence of the causes of corneal blindness in atleast one eye for the different age groups for the four areas ofAPEDS combined
Corneal blindness 1.trauma and keratitis in males 2.traditional medicine and post cataract Sx - females
Demographic associations of corneal blindnessNone of the participants of upper socio-economic class have blindness due to corneal disease
Visual acuity distribution99 eye suffered from corneal blindness
26 eyes of 13 patients – B/l
73 eyes of 73 patients – U/l
< 20/200 to 20/400 – 9.1%
20/400 to PL – 39.4%
PL to NPL – 51.5%
Extrapolations to the population Estimated A.P. population 2001 – 76 million Extrapolated data from APEDS – Atleast one eye – 50,160 Both eyes – 7600
Estimated Indian population 2001 – 1027 million Extrapolated data from APEDS – Atleast one eye – 6.8 million Both eyes – 1 million
Prevalence - India by 2010 and 2020 2010 – 8.4 of 1168 million population 2020 – 10.6 of 1312 million population, will have corneal blindness
Discussion
The major causes of corneal blindness globally include – Trachoma, corneal ulceration, Xerophthalmia, ophthalmia
neonatorum, traditional eye medicines, onchocerciasis, leprosy, and ocular trauma
These population based data suggest that 0.66% of this Indian population suffers from corneal blindness in at least one eye i.e. one out of every 150 people
Prevalence and demographic association There was a regional variation in the prevalence of corneal blindness.
low prevalence in urban is due to the better socioeconomic status leading to better nutrition and, thereby, reduced prevalence of vitamin A deficiency associated with exanthematous fever.
People from rural areas with corneal blindness in both eyes have migrated to urban areas thus. urban area had a high prevalence of corneal blindness
Causes of corneal blindness Keratitis during childhood was the leading cause of corneal blindness in our population
Malnourished children - debilitating fever - Vitamin A deficiency - blindness due to xerophthalmia ( most common males)
Trauma was the second major cause of corneal blindness in our population - most important causes of unilateral vision loss in developing countries ( most common males 3:1)
Work place associated – 40%
Corneal scar following keratitis during adulthood was the next common cause of corneal blindness in our population (50 years of age or more)
Recently, corneal ulceration has also been recognised as a “silent epidemic” in developing countries
Corneal blindness related to cataract surgery - aphakic bullous keratopathy, females had a 2.5 times higher risk
Role of corneal grafting Most of the corneal blind cases can be visually rehabilitated by corneal grafting Indications – V.A <20/200 to PL
Corneal grafting issues Trained corneal surgeons with well equipped clinical facilities for proper surgery, long term
follow up, and treatment of graft rejections and other postoperative complications that might occur, can successfully perform corneal grafting
The selection of a candidate for corneal grafting. Hospital based data on survival of corneal grafts done at a reputed eye institute in India showed that the 5 year survival rate for corneal transplants performed for the first time was 46.5% for all pathologies causing corneal blindness
The third major issue is availability of adequate number of good quality donor corneas for corneal grafting from reliable eye bank facilities
The fourth issue is that the surgical costs
Need for health promotion strategies Of the 0.66% prevalence of corneal blindness in our population 95% were avoidable
Prevention is more cost-effective as seen in some parts due to – 1. Corneal blindness due to Vit A def2. Onchocerciasis3. Leprosy
Health promotion programmers should be conducted mainly targeting risk groups –
4. Schools5. Factories6. Universal immunization
Achieved through Gov., non-gov., eye health professionals, health care promotional programmers which focus on awareness, risk and consequence of corneal blindness and possible safety and preventive procedures
Vision 2020 : To reduce prevalence of preventable and curable corneal blindness
Strategies for control of corneal blindness General Strategies Disease specific Strategies Eye injuries Trachoma Blindness Prevention of Xerophthalmia Ban on traditional eye medication and quacks Protective measures Keratoplasty and Eye Banking