Ecological determinants of blindness in Nigeria: the Nigeria National Blindness and Visual Impairment Survey

M M Rabiu, Murthy V S Gudlavalleti, C E Gilbert, Selvaraj Sivasubramaniam, Fatima Kyari, Tafida Abubakar, Nigeria National Blindness and Visual Impairment study group

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Abstract

OBJECTIVE: To determine the prevalence and causes of visual loss in different ecological zones across Nigeria.
METHODS: A population-based survey using multi-stage, stratified, cluster random sampling with probability proportional to size comprising a nationally representative sample of adults aged >40 years from six ecological zones.
OUTCOME MEASURES: Distance vision was measured using reduced logMAR charts. Clinical examination included basic eye examination for all respondents and a detailed examination including visual fields, gonioscopy and fundus photography for those who were visually impaired or blind (i.e. presenting vision <20/40 in the better eye). A principal cause of visual loss was assigned to all respondents with presenting vision <20/40 in the better eye.
RESULTS: A total of 15 122 persons aged >40 years were enumerated, 13 599 (89.9%) of whom were examined. The prevalence of blindness varied according to ecological zone, being highest in the Sahel region (6.6%; 95% confidence interval (CI) 4.2 - 10.4) and lowest in the rain forest region (3.23%; 95% CI 2.6 - 3.9). Age/gender-adjusted analyses showed that risk of blindness was highest in Sahel (odds ratio (OR) 3.4; 95% CI 2.1 - 5.8). More than 80% of blindness in all ecological regions was avoidable. Trachoma was a significant cause only in the Sudan savannah belt. The prevalence of all major blinding conditions was highest in the Sahel.
CONCLUSIONS: The findings of this national survey may be applicable to other countries in West and Central Africa that share similar ecological zones. Onchocerciasis and trachoma are not major causes of blindness in Nigeria, possibly reflecting successful control efforts for both these neglected tropical diseases.
Original languageEnglish
Pages (from-to)53-58
Number of pages6
JournalSouth African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde
Volume101
Issue number1
Publication statusPublished - Jan 2011

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Vision Disorders
Blindness
Nigeria
Trachoma
Confidence Intervals
Gonioscopy
Neglected Diseases
Central Africa
Onchocerciasis
Sudan
Western Africa
Photography
Visual Fields
Odds Ratio
Surveys and Questionnaires
Population

Keywords

  • adult
  • aged
  • aged, 80 and over
  • blindness
  • environmental health
  • female
  • humans
  • male
  • middle aged
  • Nigeria
  • onchocerciasis
  • prevalence
  • trachoma

Cite this

Rabiu, M. M., Gudlavalleti, M. V. S., Gilbert, C. E., Sivasubramaniam, S., Kyari, F., Abubakar, T., & Nigeria National Blindness and Visual Impairment study group (2011). Ecological determinants of blindness in Nigeria: the Nigeria National Blindness and Visual Impairment Survey. South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde, 101(1), 53-58.

Ecological determinants of blindness in Nigeria : the Nigeria National Blindness and Visual Impairment Survey. / Rabiu, M M; Gudlavalleti, Murthy V S; Gilbert, C E; Sivasubramaniam, Selvaraj; Kyari, Fatima; Abubakar, Tafida; Nigeria National Blindness and Visual Impairment study group.

In: South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde, Vol. 101, No. 1, 01.2011, p. 53-58.

Research output: Contribution to journalArticle

Rabiu, MM, Gudlavalleti, MVS, Gilbert, CE, Sivasubramaniam, S, Kyari, F, Abubakar, T & Nigeria National Blindness and Visual Impairment study group 2011, 'Ecological determinants of blindness in Nigeria: the Nigeria National Blindness and Visual Impairment Survey' South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde, vol. 101, no. 1, pp. 53-58.
Rabiu, M M ; Gudlavalleti, Murthy V S ; Gilbert, C E ; Sivasubramaniam, Selvaraj ; Kyari, Fatima ; Abubakar, Tafida ; Nigeria National Blindness and Visual Impairment study group. / Ecological determinants of blindness in Nigeria : the Nigeria National Blindness and Visual Impairment Survey. In: South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde. 2011 ; Vol. 101, No. 1. pp. 53-58.
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abstract = "OBJECTIVE: To determine the prevalence and causes of visual loss in different ecological zones across Nigeria. METHODS: A population-based survey using multi-stage, stratified, cluster random sampling with probability proportional to size comprising a nationally representative sample of adults aged >40 years from six ecological zones. OUTCOME MEASURES: Distance vision was measured using reduced logMAR charts. Clinical examination included basic eye examination for all respondents and a detailed examination including visual fields, gonioscopy and fundus photography for those who were visually impaired or blind (i.e. presenting vision <20/40 in the better eye). A principal cause of visual loss was assigned to all respondents with presenting vision <20/40 in the better eye. RESULTS: A total of 15 122 persons aged >40 years were enumerated, 13 599 (89.9{\%}) of whom were examined. The prevalence of blindness varied according to ecological zone, being highest in the Sahel region (6.6{\%}; 95{\%} confidence interval (CI) 4.2 - 10.4) and lowest in the rain forest region (3.23{\%}; 95{\%} CI 2.6 - 3.9). Age/gender-adjusted analyses showed that risk of blindness was highest in Sahel (odds ratio (OR) 3.4; 95{\%} CI 2.1 - 5.8). More than 80{\%} of blindness in all ecological regions was avoidable. Trachoma was a significant cause only in the Sudan savannah belt. The prevalence of all major blinding conditions was highest in the Sahel. CONCLUSIONS: The findings of this national survey may be applicable to other countries in West and Central Africa that share similar ecological zones. Onchocerciasis and trachoma are not major causes of blindness in Nigeria, possibly reflecting successful control efforts for both these neglected tropical diseases.",
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AU - Sivasubramaniam, Selvaraj

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N2 - OBJECTIVE: To determine the prevalence and causes of visual loss in different ecological zones across Nigeria. METHODS: A population-based survey using multi-stage, stratified, cluster random sampling with probability proportional to size comprising a nationally representative sample of adults aged >40 years from six ecological zones. OUTCOME MEASURES: Distance vision was measured using reduced logMAR charts. Clinical examination included basic eye examination for all respondents and a detailed examination including visual fields, gonioscopy and fundus photography for those who were visually impaired or blind (i.e. presenting vision <20/40 in the better eye). A principal cause of visual loss was assigned to all respondents with presenting vision <20/40 in the better eye. RESULTS: A total of 15 122 persons aged >40 years were enumerated, 13 599 (89.9%) of whom were examined. The prevalence of blindness varied according to ecological zone, being highest in the Sahel region (6.6%; 95% confidence interval (CI) 4.2 - 10.4) and lowest in the rain forest region (3.23%; 95% CI 2.6 - 3.9). Age/gender-adjusted analyses showed that risk of blindness was highest in Sahel (odds ratio (OR) 3.4; 95% CI 2.1 - 5.8). More than 80% of blindness in all ecological regions was avoidable. Trachoma was a significant cause only in the Sudan savannah belt. The prevalence of all major blinding conditions was highest in the Sahel. CONCLUSIONS: The findings of this national survey may be applicable to other countries in West and Central Africa that share similar ecological zones. Onchocerciasis and trachoma are not major causes of blindness in Nigeria, possibly reflecting successful control efforts for both these neglected tropical diseases.

AB - OBJECTIVE: To determine the prevalence and causes of visual loss in different ecological zones across Nigeria. METHODS: A population-based survey using multi-stage, stratified, cluster random sampling with probability proportional to size comprising a nationally representative sample of adults aged >40 years from six ecological zones. OUTCOME MEASURES: Distance vision was measured using reduced logMAR charts. Clinical examination included basic eye examination for all respondents and a detailed examination including visual fields, gonioscopy and fundus photography for those who were visually impaired or blind (i.e. presenting vision <20/40 in the better eye). A principal cause of visual loss was assigned to all respondents with presenting vision <20/40 in the better eye. RESULTS: A total of 15 122 persons aged >40 years were enumerated, 13 599 (89.9%) of whom were examined. The prevalence of blindness varied according to ecological zone, being highest in the Sahel region (6.6%; 95% confidence interval (CI) 4.2 - 10.4) and lowest in the rain forest region (3.23%; 95% CI 2.6 - 3.9). Age/gender-adjusted analyses showed that risk of blindness was highest in Sahel (odds ratio (OR) 3.4; 95% CI 2.1 - 5.8). More than 80% of blindness in all ecological regions was avoidable. Trachoma was a significant cause only in the Sudan savannah belt. The prevalence of all major blinding conditions was highest in the Sahel. CONCLUSIONS: The findings of this national survey may be applicable to other countries in West and Central Africa that share similar ecological zones. Onchocerciasis and trachoma are not major causes of blindness in Nigeria, possibly reflecting successful control efforts for both these neglected tropical diseases.

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JF - South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde

SN - 0038-2469

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ER -