Objective: To determine the anatomical causes and diagnosis leading to severe visual impairment and blindness
and explore their relationship to demographic characteristics among children in Mbarali district, Southern
Materials and methods: Key informants were trained on how to identify children with poor vision and other
ocular abnormalities. Key informants identified, listed and referred for examination children with poor vision,
white pupillary reflex, squint, and smaller and bigger than normal eyes. Children with a visual acuity of <6/60
in the better eye were recruited for the study. Cycloplegic refraction, anterior and posterior segment and ocular
alignment examination were performed to ascertain the cause of Severe Visual Impairment (SVI) or Blindness
Results: Sixty six children had a visual acuity (VA) of <6/60. Seventy percent were 5 years or more. The mean age
was 9.18(±4.42) (SD =4.42) years. Thirty five (53%) were females. Forty eight (72.7%) had SVI (VA<6/60) while 18
(27.3%) were BL (VA<3/60). Lens related conditions (27.3%), uncorrected refractive error (15.2%) and corneal
related disorders (13.6%) were the commonest causes of SVI/BL. Majority of children with lens related conditions
(72.2%), uncorrected refractive error and congenital glaucoma (75%) were females, while all 6 children with
cortical blindness were males. Lens related and cortical blindness conditions were commoner among under-five
than among older children (6/20, 30% vs 12/46, 26%) and (4/20,20% vs 2/46, 4%). Un-operated cataract was the
leading diagnosis causing SVI/BL. Only 4 patients were operated for cataract. There was only one patient with
phthisis-bulbi related to keratomalasia.
Conclusion and Recommendations: Lens related conditions, specifically cataract was the leading cause of
SVI/BL. Recruitment of an eye-doctor at Mbarali District Hospital and establishment of tertiary eye services at
Mbeya Zonal Referral Hospital are recommended to enable identification, referral and comprehensive tertiary
management of children with eye conditions.
Gilbert CE, Foster A. Childhood blindness in the
context of VISION 2020-The right to Sight. Bull
World Health Org. 2001; 79(3):227-232.
Gilbert C, Foster A. Blindness in children: Control
priorities and research opportunities. Br J Ophthalmol.
; 85(9): 1025-1027.
Foster A, Sommer A. Corneal ulceration, measles,
and childhood blindness in Tanzania. Br J
Ophthalmol. 1987; 71:331-343.
Muhit MA. Childhood cataract: Home to
hospital. Comm Eye Health. 2004; 17(50):19-22.
World Health Organization. Preventing blindness in
children. WHO/PBL/00.77. WHO, Geneva, 1999.
Agarwal PK, Bowman R, Courtright P. Child eye
health tertiary facilities in Africa. J AAPOS. 2010;
Kalua K, Ngongola R T, Mbewe F, Gilbert C. Using
primary health care (PHC) workers and key informants
for community based detection of blindness in
children in Southern Malawi. Human Resources for
Health. 2012; 10:37. http://www.human-resourceshealth.
Demissie BS, Solomon AW. Magnitude and causes of
childhood blindness and severe visual impairment in
Sekoru District, Southwest Ethiopia: a survey using
the key informant method. Trans R Soc Trop Med
Hyg. 2011; 105 (9):507-511.
Omolase CO, Aina AS, Omolase BO, et al. Causes of
blindness and visual impairment at the school for the
blind Owo, Nigeria. Annals Ibadan Postgraduate
Med. 2008; 6(1): 49-52
Adoh TO, Woodhouse JM. The Cardiff acuity test
used for measuring visual acuity development in
toddlers. Vision Res. 1994; 34(4):555-560.
Gilbert C, Foster A, Negrel AD, et al. Childhood
blindness: a new form for recording causes of visual
loss in children. Bull World Health Org. 1993;
(5):485 - 489.
Muhit, MA, Shah SP, Gilbert CE, Foster A.
Causes of severe visual impairment and blindness
in Bangladesh: a study of 1935 children. Br J
Ophthalmol. 2007; 91:1000 -1004.
Njuguna M, Msukwa G, Shilio B, Tumwesigye PC,
Courtright P. Causes of severe visual impairment and
blindness in children in schools for the blind in eastern
Africa: changes in the last 14 years. Ophthalmic
Epidemiol. 2009; 16(3):151-155.
Gilbert CE, Wood M, Waddel K, Foster A. Causes
of childhood blindness in East Africa: results in 491
pupils attending 17 schools for the blind in Malawi,
Kenya and Uganda. Ophthalmic Epidemiol. 1995;
Ruhagaze P, Njuguna KKM, Kandeke L, Courtright P.
Blindness and severe visual impairment in pupils at
schools for the blind in Burundi. Middle East Afr J
Ophthalmol. 2013; 20(1):61-65.
Arunga S, Onyango J, Ruvuma S, Twinamasiko A.
Prevalence and causes of blindness and severe visual
impairment (BL/SVI) among children in Ntungamo
district, southwestern Uganda: a key informant crosssectional
population survey. J Ophthalmol East Cent
& S Afr. 2016; 20(1): 26-32.
Gogate DP, Ramsonet P, et al. Surgery for sight:
outcomes of congenital and developmental cataracts
operated in Durban, South Africa. Eye. 2016; 30:
Msukwa G, Njuguna M, Tumwesigye C, Shilio
B, Courtright P, Lewallen S. Cataract in children
attending schools for the blind and resource centers in
eastern Africa. Ophthalmology. 2009; 116(5):1009-12.
Wedner SH, Ross DA, Balira R, Kaji L, Foster A.
Prevalence of eye diseases in primary school children
in a rural area of Tanzania. Br J Ophthalmol. 2000;
:1291–1297. http://bjo.bmj.com/ on November
Kisimbi J, Shalchi Z, Omar A, et al. Macular spectral
domain optical coherence tomography findings in
Tanzanian endemic optic neuropathy. Brain. 3418
– 3426. DOI: http://dx.doi.org/10.1093/brain/awt221
Hodson KE, Bowman RJ, Mafwiri M, Wood M, Mhoro
V, Cox SE. Low folate status and indoor pollution are
risk factors for endemic optic neuropathy in Tanzania.
Br J Ophthalmol. 2011; 95(10):1361-4. doi: 10.1136/
bjo.2010.197608. Epub 2011 Jul 6.
Flitcroft DI. Emmetropisation and the aetiology of
refractive errors. Eye. 2014; 28: 169 -179.
Laura A, Alberto P, Mercedes V, Paz CM, Francisco
M. Fetal sex and perinatal outcomes. J Perinat Med.
Viegas OA, Lee PS, Lim KJ, Ravichandran J. Male
fetuses are associated with increased risk for cesarean
delivery in Malaysian nulliparae. Medscape J Med.
; 10(12):276. [PMC free article] [PubMed])