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