Abstract

CABRERA MARTINEZ, Abel; RIO TORRES, Marcelino; HERNANDEZ SILVA, Juan R.  and  PADILLA GONZALEZ, Carmen M.. Prevalence of blindness and severe visual shortage in over 50 years-old adults in the City of Havana province. Rev Cubana Oftalmol [online]. 2007, vol.20, n.2, pp. 0-0. ISSN 1561-3070.

The universe of a cross-sectional descriptive study, which was carried out from June 2004 to June 2005, was made up of people aged over 50 years, who lived in the City of Havana. In order to determine the sample size, 633 396 over 50 years-old inhabitants were taken as the universe of study, with an expected prevalence estimation of 4.0 %, an allowable error of 3 % and a design effect of 70 %. On the basis of these data, systematic cluster sampling was made to determine a sample of 2 760 inhabitants from the City of Havana, represented by 46 clusters of 60 subjects each. Blindness was defined as corrected visual acuity lower than 20/400 and severe visual shortage as corrected visual acuity >20/400 and <20/200 in the best eye and with the best available correction. An inter-observer variation to reduce errors for this reason was also made. The study coverage was 98.4 % of the selected sample. The blindness prevalence by sex was 2.4 %. Prevalence of bilateral blind persons by age increases from 2.6 % at 50 years to 15,2 % at 80 years and over. The most important causes of bilateral blindness were cataract (50 %), glaucoma (26 %) and diabetic retinopathy (9 %) for a total number of 15 201 bilateral blind people due to all these causes, 27 236 with low vision and 42 437 individuals with visual acuity under 20/200 of whom 16 468 were affected by cataract. The main barriers to cataract surgery was mostly found in the group of persons (41 %) who stated that they did not know they had this disease; 25.2 % of responses came from individuals who presented with a disease that contraindicated the surgery; 10.1 % of responses were given by those waiting for cataract maturation and 6.5 % did not have any accompanying person to take care of them after being operated on.

Keywords : Corneal trachomatose opacity; pinhole bulb; confidence interval; cataract blindness; severe visual deficit from cataract; cataract surgery contraindicated by a disease.