Cataract is defined as partial or complete opacification of the crystalline lens and is considered the primary cause of vision loss worldwide (1).It is the leading cause of blindness accounting for nearly 48% of blindness globally (2). Although the actual mechanism of cataract development remains unclear, several risk factors have been established, including age, sunlight (UV) exposure ,corticosteroid use, trauma, hypertension, Diabetic Mellitus, and smoking, have resulted in a large public health burden (3).The studies also found higher prevalence of self-reported cataract among individuals with lower income, lower education, urban residency, female sex,, and intake of antidepressants (4, 5).
Along with the aging population and extended life expectancy, the number of people with cataract is expected to increase continuously. Cataract can be cured by surgery, which ranks as the most cost-effective intervention with financial return on investment(6). Currently, the standard treatment for cataract is surgical extraction of the opaque lens with an implantation of an artificial lens (7).
A study reported that lack of awareness of cataract and its treatment option and the cost of surgery to be the two main barriers to the uptake of cataract surgical services in Latin America(8). Cataract remains a concern for public health, especially in low- and middle-income countries. A total of $5733 million investment was estimated to be required for eliminating blindness due to cataract between 2010 and 2020(9).
According to a World Health Organization (WHO) report, un-operated cataract accounts for 25% of the global visual impairment burden, second only to refractive errors which accounts for 53% of visual impairments. Cataract has caused worldwide > 50% vision loss, including 33.4% blind people and 18.4% people with moderate-to-severe visual impairment(10). Globally, 10.8 million were blind and 35.1 million people were visually impaired from cataract in 2010(1, 10). Cataract causes vision loss in over 80 million people and blinds 18 million worldwide (11).Age-related cataracts constitute approximately 50% of the 285 million visually-impaired people globally; 39 million (13.7%) of whom are blind (12).
Over 90% of cataract cases are concentrated in individuals aged ≥ 50 years in lower middle income countries (LMICs) where health care access is limited. Similarly, approximately 80% and 90% of cataract related blindness, and visually impairment are concentrated LMICs respectively (11, 13, 14). In Sub-Saharan Africa, they account for 50% of the 26 million visually-impaired people, 5.9 million (22.7%) of whom are blind (15, 16).Despite Sub-Saharan Africa (SSA) having one of the highest prevalence of cataracts and cataract related blindness, it remains a grossly underserved region (17).
Visual impairment can cause disabilities by significantly interfering with one’s ability to function independently. These disabilities limit personal or socioeconomic independence and a visual handicap exists. The good news is that more than two third of this visual impairment and blindness can be avoidable either by prevention and treatment. According to ‘vision 2020 the right to sight’ plan, in 2020 preventable and avoidable causes of visual impairment and blindness will be reduced significantly to less than 0.5% in all countries or less than 1% in any community worldwide (18, 19).
Ethiopia is believed to have one of the world’s highest rates of blindness (1.6%) and low vision (3.7%), of which more than 80% is either treatable or preventable .Cataract is the first leading cause of low vision in Ethiopia accounting for 42.3% and the leading cause of blindness accounting for 49.9%(20). Different studies showed that cataract is a problem that apparent in different countries with different magnitude For instance is: 47.5% in southern India(21), 11.6% in puducherry, India (22), 19.8% in Nigeria (23), 20% in Nigerian tertiary hospital(24), 14.2% in korea (25), 39.05% in Gahna (26). Several studies showed that various factors were positively associated with cataract such as ageing, sex, educational level, occupation residence, occupation, family size, household wealth status and educational level (3, 27). And also, smoking ,alcohol consumption ,diabetes, hypertension and obesity and Environmental factors such as trauma (eye injury) and UV/sunlight exposure have been associated with cataract (1, 2).
Therefore, knowing the prevalence of cataract and its associated factors in the community early helps to avoid blindness and gives as an input for successful implementation of VISION 2020 programmers in Ethiopia. However, there were few studies done on the prevalence of cataract and associated factors among adult patients aged 40 and above by community based study in Ethiopia in general, and no study was done in the study area in particular. Therefore, the aim of this study was to assess the prevalence of cataract and associated factors among adult patients aged 40 and above in the study area.