National survey of blindness and visual impairment

Women waiting to be examined during the Nigeria national survey

Caption: Women waiting to be examined during the Nigeria national survey

Identifying priorities for eye disease control and services

1. Bangladesh
2. Pakistan
3. Nigeria
4. Sri Lanka

National surveys of blindness and visual impairment are important as they provide national estimates of the number who are visually impaired or blind by cause for use in advocacy with policy makers so that more resources are made available for eye, and for programme planners so that services are developed which respond to the need in the population.

ICEH has collaborated with Ministries of Health and in-country teams, giving technical input to four large, national population based surveys of blindness and visual impairment, in Bangladesh, Pakistan, Nigeria and Sri Lanka. All included adults aged 40 years and above apart from Bangladesh where those aged 30-39 years were also included.

All the surveys had a similar design, using stratified cluster randomized sampling, with proportional to size methods. All participants were interviewed, and had their height and weight measured. Illiterate E charts were used to measure visual acuity, and standard equipment was used for diagnosis in all those who failed the visual acuity screening test of 6/12 in at least one eye. All participants who failed vision screening were refracted by optometrists who assessed best corrected visual acuity measured. World Health Organization algorithms were used to assign a cause of visual impairment or blindness for each affected individual. All the surveys included equipment for retinal imaging, and visual field screening was also included. In each country two teams comprising ophthalmologists, optometrists and ophthalmic nurses undertook the field work, under the supervision and guidance of a Project Manager. Comprehensive quality assurance mechanisms were built in, including inter-observer agreement studies, frequent calibration of equipment, daily checking of data collection instruments and double data entry.

Dissemination meetings have taken place within country where the findings have been presented to relevant stake holders.

Sightsavers was the main funding agency for all the surveys, and Sightsavers Country office staff played important roles, including financial management and logistical support.

1.Bangladesh

Sponsors

Publications

  1. Bourne RR, Dineen BP, Ali SM, Noorul Huq DM, Johnson GJ. Prevalence of refractive error in Bangladeshi adults: results of the National Blindness and Low Vision Survey of Bangladesh. Ophthalmology. 2004 Jun;111(6):1150-60. Article.
  2. Bourne RR, Dineen BP, Huq DM, Ali SM, Johnson GJ. Correction of refractive error in the adult population of Bangladesh: meeting the unmet need. Invest Ophthalmol Vis Sci. 2004 Feb;45(2):410-7. Abstract.
  3. Dineen BP, Bourne RR, Ali SM, Huq DM, Johnson GJ. Prevalence and causes of blindness and visual impairment in Bangladeshi adults: results of the National Blindness and Low Vision Survey of Bangladesh. Br J Ophthalmol. 2003 Jul;87(7):820-8. Abstract.
  4. Bourne RR, Dineen BP, Ali SM, Huq DM, Johnson GJ. Outcomes of cataract surgery in Bangladesh: results from a population based nationwide survey. Br J Ophthalmol. 2003 Jul;87(7):813-9. Abstract.
  5. Bourne RR, Dineen B, Modasser Ali S, Mohammed Noorul Huq D, Johnson GJ. The National Blindness and Low Vision Prevalence Survey of Bangladesh: research design, eye examination methodology and results of the pilot study. Ophthalmic Epidemiol. 2002 Apr;9(2):119-32. Abstract.

2. Pakistan

Sponsors

Publications

  1. Jadoon Z., Dineen B., Bourne RRA., Shah SP., Khan A., Johnson , Gilbert CE., Khan MD. On behalf of the Pakistan National Eye Survey Study Group. Prevalence of blindness and visual impairment in Pakistan. The Pakistan National Blindness and Visual impairment Survey. Invest. Ophth. Vis. Sci. Invest Ophthalmol Vis Sci. 2006 47: 4,749-55.
  2. Dineen B, Bourne RR, Jadoon Z, Shah SP, Khan MA, Foster A, Gilbert CE, Khan MD. Causes of blindness and visual impairment in Pakistan. The Pakistan National Blindness and Visual impairment Survey. Br J Ophthalmol. 2007 91 1,005-10.
  3. Jadoon Z, Shah SP, Bourne RR, Dineen B, Khan MA, Gilbert CE, Foster A, Khan MD. Cataract prevalence, cataract surgical coverage and barriers to uptake of cataract surgical services in Pakistan: The Pakistan National Blindness and Visual Impairment Survey. Br J Ophthalmol. 2007 91(8):1005-10
  4. Shah SP, Minto H, Jadoon MZ, Bourne RR, Dineen B, Gilbert CE, Khan MD; on behalf of the Pakistan National Eye Survey Study Group. Prevalence and Causes of Functional Low Vision and Implications for Services: The Pakistan National Blindness and Visual Impairment Survey. Invest Ophthalmol Vis Sci. 2008 49: 887-893.
  5. Gilbert CE, SP Shah, MZ Jadoon, R Bourne, B Dineen, MA Khan, Johnson GJ, and MD Khan. ‘On behalf of the Pakistan National Eye Survey Study Group.’  Poverty  and visual disability in Pakistan. Results of the Pakistan National Blindness and visual impairment survey. BMJ. Jan 2008 336 (7634): 29-32.
  6. Taylor A, SP Shah, Gilbert CE, MZ Jadoon, R Bourne, B Dineen, GJ Johnson and MD Khan. ‘On behalf of the Pakistan National Eye Survey Study Group. Visual function and quality of life among visually impaired and pseudo/aphakic adults in Pakistan.  The Pakistan National Blindness and Visual Impairment survey. Ophthal. Epidemiol. 2008 15: 242-9
  7. Shaheen P Shah, Zahid Jadoon, Brendan Dineen, Rupert RA Bourne, Gordon J Johnson, Clare E Gilbert and Mohammad D Khan. ‘On behalf of the Pakistan National Eye Survey Study Group.’ Refractive errors in Pakistani adults, prevalence and spectacle coverage. The Pakistan National Blindness and Visual Impairment Survey. Ophthalmic Epidemiol. 2008 15 183-190.

 

3. Nigeria

This national survey, of adults aged 40 years and above, entailed examining over 13,500 individuals in 305 locations across Nigeria.

Findings have been disseminated widely and were used to draft the National Prevention of Blindness Plans. Additional resources have also been provided by the Ministry of Health for Eye Care.

Sponsors

Publications

  1. Dineen Brendan, Gilbert Clare, Rabiu M Mansur, Kyari Fatima, Abdull M Mahdi, Tafida Abubakar, Ezelum Christian, Entekume Gabriel, Adenike Abiose, Hannah Faal, Jonathon J Jiya, Chinenyem P Ozemela, Pak Sang Lee and Murthy VS Gudlavalleti. The Nigerian National Blindness and Visual Impairment Survey: Rationale, objectives and detailed methodology. BMC 2008 8: 17.
  2. Kyari F., Gudlavalleti Murthy V S, Sivsubramaniam S., Gilbert CE.,  Abdull MA., Entekume G., Foster A. and Nigeria National Blindness and Visual Impairment Study Group. Prevalence of Blindness and Visual Impairment in Nigeria: The national blindness and visual impairment survey. Invest Ophthalmol Vis Sci. 2009 50: 2033-9.
  3. Abdull MM, Sivasubramaniam S, Murthy GV, Gilbert C, Abubakar T, Ezelum C, Rabiu M. Causes of Blindness and Visual Impairment in Nigeria: The Nigeria National Blindness and Visual Impairment Survey. IOVS 2009 50(9): 4,114-20
  4. Gilbert CE., Murthy GVS., Sivasubramaniam S., Kyari F., Imam A., Rabiu MM., Abdull M and Tafida A. Couching in Nigeria: prevalence, risk factors and visual acuity outcomes. Ophthalmic Epidemiol. 2010 Oct;17(5):269-75.
  5. Rabiu MM, Gilbert CE, Murthy VS Gudlavalleti, Selvaraj Sivasubramaniam Fatima Kyari, Abdul Usman Imam, Tafida Abubakar on behalf of Nigeria National Blindness and Visual Impairment Study Group. Ecological determinants of blindness in Nigeria. S African Med J. 2011 101: 53-58
  6. Imam AU., Gilbert CE., Sivasubramaniam S., Murthy GVS., Maini R. and Rabiu MM on behalf of the Nigeria National Blindness and Visual Impairment Study Group. Outcome of cataract surgery in Nigeria: visual acuity, autorefraction and optimal Intraocular Lens powers- Results from Nigeria National Survey. Ophthalmology 2011 118: 719-724
  7. Ezelum C., Razavi H., Selvaraj S., Gilbert C.E., Murthy G.V.S., Entekume G., Tafida A. and the Nigeria National Blindness and Visual Impairment Study Group. Refractive errors in Nigerian adults: prevalence, types and spectacle coverage. Ophthalmol. Vis. Sci. 2011;52 5449-5456
  8. Hang My Tran, Abdull MM, Selvaraj Sivasubramaniam, Murthy VS Gudlavalleti, Clare E Gilbert, Shaheen P Shah, Ezelum CC, Tafida Abubakar, and Bankole Olufunmilayo O. on behalf of the Nigeria National Blindness and Visual Impairment Study Group. Quality of life and visual function in Nigeria: findings from the National Survey of blindness and visual impairment. Br J Ophthalmol 2011 95:1646-51.
  9. Entekume G., Murthy G.V.S., Selvaraj S., Jaymini and Gilbert C.E. Prevalence, causes, and risk factors for functional low vision in nigeria: Results from the national survey of blindness and visual impairment. IOVS 2011 52: 6714-19.
  10. Abubakar T, Gudlavalleti MV, Sivasubramaniam S, Gilbert CE, Abdull MM, Imam AU. Coverage of hospital-based cataract surgery and barriers to the uptake of surgery among cataract blind persons in nigeria: the Nigeria National Blindness and Visual Impairment Survey. Ophthalmic Epidemiol. 2012 Apr;19(2):58-66.
  11. M Mansur Rabiu, Fatima Kyari, Christian Ezelum, Elizabeth Elhassan, Safiya Sanda, Gudlavalleti, V.S.Murthy, Selvaraj Sivasubramaniam, Clare Glibert and the Nigeria National Blindness and Visual Impairment study group. Review of the publications of the Nigeria national blindness survey: Methodology, prevalence, causes of blindness and visual impairment and outcome of cataract surgery.Annals of African J Med. 2012 11: 125-130.
  12. Gudlavalleti VS Murthy, Samantha Fox, Selvaraj Sivasubramaniam, Clare E Gilbert, Abdull M Mahdi, Abdullahi U Imam, Gabriel Entekume on behalf of the Nigeria National Blindness and Visual Impairment Study Group. Prevalence and risk factors for hypertension and association with ethnicity in Nigeria: results from a national survey.  Cardiovasc J Afr. 2013 Sep 11; 24:1 -7
  13. Abdull M Mahdi, Mansur Rabiu, Clare Gilbert, Selvaraj Sivasubramaniam,Gudlavalleti VS Murthy, Christian Ezelum, Gabriel Entekume6 on behalf of the Nigeria National Blindness and Visual Impairment Study Group. Prevalence and risk factors for lens opacities in Nigeria: results of the national blindness and low vision survey. IOVS 2014 55 2642-2651
  14. Kyari F, Tafida A, Sivasubramaniam S, Murthy GV, Peto T, Gilbert CE. Prevalence and risk factors for diabetes and diabetic retinopathy: results from the Nigeria national blindness and visual impairment survey. BMC Public Health 2014, 14:1299
  15. Tafida A, Kyari F, Abdull M M, Sivasubramaniam S , Murthy GVS, and Gilbert CE on behalf of the Nigeria National Survey of Blindness and Visual Impairment Study Group. Poverty and blindness in Nigeria: findings from the national survey of visual impairment and blindness. Oph Epi. In press.
  16. Ramke J., Zwi AB., Palagy A., Blignault I and Gilbert CE. Equity and blindness: closing evidence gaps to support Universal Eye Health. Ophthalmic Epidemiol. 2015 In press

 4. Sri Lanka

Limited data are available on the prevalence and causes of blindness and visual impairment in Sri Lanka. Data collection for a national survey has just been completed during which almost 7000 adults were examined across the country. Data arising from this survey will be used to identify priorities for control and to plan eye care services.

Funders

 

Comments are closed.