A recent estimate by the World Health Organization (WHO) suggests that 161 million persons worldwide have visual impairment, including 37 million blind (best-corrected visual acuity less than 3/60 in the better eye) and 124 million with visual impairment less severe than blindness (best-corrected acuity less than 6/18 to 3/60 in the better eye). This estimate is quoted widely, but because it is based on definitions using best-corrected visual acuity, uncorrected refractive error as a cause of visual impairment is excluded. We reviewed data from population-based surveys of visual impairment worldwide published 1996 onwards that included presenting visual acuity, and estimated the proportion of visual impairment caused by uncorrected refractive error in different sub-regions of the world. We then extrapolated these data to estimate the worldwide burden of visual impairment including that caused by uncorrected refractive error. The total number of persons with visual impairment worldwide, including that due to uncorrected refractive error, was estimated as 259 million, 61% higher than the commonly quoted WHO estimate. This includes 42 million persons with blindness defined as presenting visual acuity less than 3/60 in the better eye, and 217 million persons with less severe visual impairment level defined as presenting visual acuity less than 6/18 to 3/60 in the better eye, 14% and 75% higher, respectively, than the WHO estimates based on best-corrected visual acuity. Sensitivity analysis, taking into account the uncertainty of the proportion of visual impairment caused by refractive error, revealed that the number of persons in the world with visual impairment due to uncorrected refractive error could range from 82 to 117 million. The actual burden of visual impairment worldwide, including that caused by uncorrected refractive error, is substantially higher than the commonly quoted WHO estimate that is based on best-corrected visual acuity. We suggest that the indicative estimate of 259 million persons with visual impairment worldwide, which includes 42 million blind with visual acuity less than 3/60 in the better eye, be used for further planning of the VISION 2020 initiative instead of the often quoted 161 million estimate that includes 37 million blind.

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What is the global burden of visual impairment

https://www.ph.ucla.edu/epi/rapidsurveys/ophthalmology114(3)_599_605_2007.pdf

Rapid assessment of avoidable blindness in Nakuru district, Kenya.

Background: Cataract remains the leading cause of global blindness. Evidence from population-based surveys, carried out up to 2000, and the launch of the VISION 2020 initiative to address avoidable blindness showed that women in low- and middle-income countries had a lower cataract surgical coverage (CSC) than men. Methods: A systematic review identified population-based surveys reporting CSC in low- and middle-income countries published since 2000. Researchers extracted data on sex-specific CSC rates and estimated the overall CSC differences using meta-analyses. Results: Among the 23 surveys selected for this review, 21 showed higher CSC among men. The Peto odds ratio revealed that men were 1.71 times (95% CI 1.48 to 1.97) more likely to have cataract surgery than women. The risk difference in the rates of surgery varied from −0.025 to 0.276, and the combined average was 0.116 (95% CI 0.082 to 0.149). Discussion: Gender inequity in use of cataract surgical services persists in the low- and middle-income countries. It is estimated in this study that blindness and severe visual impairment from cataract could be reduced by around 11% in the low- and middle-income countries if women were to receive cataract surgery at the same rate as men. Additional effort globally is needed to ensure that women receive the benefits of cataract surgery at the same rate as men.

https://bjo.bmj.com/content/bjophthalmol/93/3/295.full.pdf

Cataract surgical coverage remains lower in women

Aim: To estimate the prevalence of visual impairment and blindness caused by cataract, the prevalence of aphakia/pseudophakia, cataract surgical coverage (CSC) and to identify barriers to the uptake of cataract services among adults aged ⩾30 years in Pakistan. Methods: Probability proportional-to-size procedures were used to select a nationally representative sample of adults. Each subject underwent interview, visual acuity measurement, autorefraction, biometry and ophthalmic examination. Those that saw Results: 16 507 Adults were examined (95.5% response rate). The crude prevalence of blindness (presenting Conclusion: Approximately 570 000 adults are estimated to be blind (

/pdf/cataract-prevalence-cataract-surgical-coverage-and-barriers-4m520xhztz.pdf

Cataract prevalence, cataract surgical coverage and barriers to uptake of cataract surgical services in Pakistan: the Pakistan National Blindness and Visual Impairment Survey

Severe falciparum malaria: a case report.

Objective: To evaluate the clinical, biochemical and sonographic changes in patients with falciparum malaria and jaundice. Study Design: A case series. Place and Duration of Study: This study was conducted at Medical Unit-I (Ward 5), Jinnah Postgraduate Medical Centre, Karachi, from January 2006 to November 2007. Methodology: A total of 62 adult patients, regardless of age and gender, with peripheral blood film evidence of falciparum malaria, who had jaundice, were included. Any patient with evidence of infection with Plasmodium vivax or other causes of liver disease (e.g. viral hepatitis, cirrhosis, portal hypertension, amoebic liver abscess, unexplained hepatomegaly, ascites, history of alcoholism, taking hepatotoxic drugs, past history of jaundice) was excluded on the basis of history, relevant clinical examination and investigations. Results: Age of the patients ranged from 13-48 years (mean 26.04±8.33). All patients were febrile and icteric, with pallor in 67.7%, hepatomegaly in 30.6%, splenomegaly in 70.9% and impaired consciousness in 20%. Serum bilirubin levels ranged from 3 to 24 mg%. Thirty two (51.6%) had serum bilirubin 3-6 mg%, 20 (32.2%) had 6-10 mg% and 10 (16.1%) had >10 mg%. ALT levels ranged from 20-870 IU/L and AST levels 24-1210 IU/L respectively. INR ranged from 1-1.3. Twenty eight patients (45%) had predominantly conjugated or mixed hyperbilirubinemia and serum transaminases were more than three times normal. Ultrasonography revealed hepatomegaly with decreased echogenicity in 22 (35.4%), splenomegaly in 48 (77.4%) and both hepatomegaly and splenomegaly in 16 (25.8%). Gallbladder wall thickness was increased in 5 (8.06%) patients. There was no evidence of biliary dilatation. Conclusion: A significant percentage of patients having falciparum malaria with jaundice fulfill the criteria for malarial hepatopathy. It should be considered in patients presenting with acute febrile illness with jaundice so that specific treatment can be given.

/pdf/malarial-hepatopathy-in-falciparum-malaria-59hh68d9b1.pdf

Malarial hepatopathy in falciparum malaria.

Objective To assess the prevalence and pattern of eye diseases in children aged 5-15 years. Design Population based cross-sectional survey. Place and duration of study Bazzertaline area of Karachi (South) from July to August, 2003. Patients and methods A community-based survey was carried out at the Bazzertaline Area, South Karachi, Pakistan on 5110 children 5-15 years of age. The socioeconomic status of the area was low, with many living below the poverty line. The survey used the WHO definitions of visual impairment as criteria for classification. Standard Snell's literate and illiterate charts were used for assessing the visual acuity. An anterior segment examination with a torch light and loupe was carried out and the posterior segment examined with a direct ophthalmoscope, initially without pupil dilation. Suspected cases of amblyopia, albinism, traumatic cataract and squint, etc. were examined with pupil dilatation. Results Refractive error of 2% was found to be the primary ocular morbidity, followed by conjunctivitis 1.2%, and squint was found as third ocular morbidity with the prevalence of 0.6%. Those diseases that were less than 0.5% included unilateral amblyopia, corneal ulcer/opacity, cataract, aphakia, trauma, blepharitis, albinism, stye, chalazion and unilateral/bilateral blindness. Bilateral blindness was present in 2.7/1000 children, the major causes being cataract and corneal diseases. Low vision was found in 2.2%, the leading cause being uncorrected refractive error. Visual acuity according to 2.42%. Gender showed higher visual impairment in girls as compared to boys 1.72%. Only one case of vitamin-A deficiency was seen. Conclusion Provision of spectacles would address the most commonly found problem of uncorrected refractive error. Lack of trained personnel and facilities for low vision services in addition to lack of advocacy and awareness in the community contribute to the pattern of eye disease in the area.

Pattern of eye diseases in children of 5-15 years at Bazzertaline Area (South Karachi) Pakistan.

OBJECTIVE: To assess the rapid assessment of cataract blindness and surgical services in age group 50 years and above. DESIGN: A cross-sectional survey. PLACE AND DURATION OF STUDY: This survey was conducted in District Lower Dir, Malakand Division, NWFP, Pakistan, from March 9-23, 2003. PATIENTS AND METHODS: A community-based survey was carried out with systematic cluster random sampling. The survey was preceded by a pilot study in which the proforma and operational methods were field-tested and refined. One thousand, one hundred and fifty eligible adults of 50 years and older were selected by systematic random sampling from the whole lower Dir district of Malakand, Pakistan. A total of 1076 subjects (93.6%) were examined. The visual acuity of each eye was assessed using tumble Snellen's E Card method at 6 and 3 meters. Any subject having visual acuity <3/60 with or without obvious lens opacity or with aphakia (removal of lens) or pseudophakia (removal of cataract lens and implantation of artificial lens) was examined in detail. The surgical services were assessed by measuring the prevalence of pseudophakia, surgical outcome of visual acuity and also the effect of place of surgery on outcome. RESULTS: Prevalence of total bilateral blindness was 2.6%, and unilateral blindness 2.46%. Total prevalence of aphakia was 2.4%, which was almost equal in both sexes, male 2.3% and female 2.4%. Prevalence of unilateral aphakia was 0.3 % in females being slightly higher than males, 0.16 %. The prevalence of bilateral aphakia was 2.2% and 2% in males and females respectively. Prevalence of total pseudophakic eyes was 2.74%. Surgical outcome showed good, borderline and poor visual acuity of 40.5%, 22% and 14.3% respectively. Surgical outcome was also seemed to be better in private hospitals as compared to field camps. CONCLUSION: It is concluded that to reduce the prevalence of blindness there was a need to improve the quality of services in mobile camps and fixed facilities. At the same time the visual outcome of surgery could be improved by expanding the number of Intraocular lens procedures and routine monitoring of cataract outcome.

Tariq M Aziz

Papers

Malarial hepatopathy in falciparum malaria.

Pattern of eye diseases in children of 5-15 years at Bazzertaline Area (South Karachi) Pakistan.

Rapid assessment of cataract surgical services in age group 50 years and above in Lower Dir District Malakand, Pakistan.