Discussion
Researchers were initiated to conduct this study due to the observation of CO in the study area. Therefore, determining the prevalence and associated factors of CO can help advocators, planners, eye healthcare providers and other concerned stakeholders increase awareness of the prevention of CO and pledging corneas, allocate appropriate resources and create collaborations to prevent and reduce CO. Therefore, this study intended to assess the prevalence and associated factors of CO among adults in Kolladiba town, Northwest Ethiopia.
In this study, the prevalence of CO was 27.2% (95% CI 24.4% to 30.4%). The findings of this study showed that being aged 49–60 years (AOR=1.90; 95% CI 1.03 to 3.32), being aged older than or equal to 61 years (AOR=2.12; 95% CI 1.17 to 3.87); being unable to read and write (AOR=2.65; 95% CI 1.68 to 4.16), having a middle-level income (AOR=2.12; 95% CI 1.30 to 3.47), having a poor income level (AOR=4.96; 95% CI 3.04 to 8.09), being a housewife (AOR=0.24; 95% CI 0.12 to 0.48) and being a student (AOR=0.28; 95% CI 0.80 to 0.89) were factors associated with CO.
Several previous studies in different parts of the world estimated the prevalence of CO as depicted in a comparison table for further information (online supplemental table 4).12 24 25 30–37
The result of CO in this study was greater than that reported in a study conducted in Australia in 2005 (3%) and in 2010 (3.3%).30 31 Additionally, studies conducted in India in 2015 among the rural Indian population and in 2016 among the rural population in Bihar reported 3.7% and 2.35% CO, respectively.32 33 Similarly, the findings of the present study were greater than those of a population-based study and the Tehran Geriatric Eye Study (TGES) in 2017 and in 2022 in Iran, which showed 1.68% and 9.58%, respectively, of CO.12 24 In addition, studies conducted by Mahdi et al34 and Durkin et al35 reported 4.1% and 1.3%, respectively, of CO; these findings were also lower than our findings. Studies conducted in 2012 and 2017 in Nigeria indicated 10.4%25 and 2%36 CO, respectively. The disparity in findings across studies may be because of the differences in the study population according to age, study setting, the selection of outcome variables and other characteristics. For instance, studies conducted in Australia and Myanmar reported only trachomatous CO,30 31 35 and the study participants were children in a study performed by Mahdi et al.34 In addition, the difference in the study’s outcome may be justified by poor health insurance coverage in Ethiopia,38 and we hypothesise that the higher prevalence of CO in our study when compared with the above-cited articles may point to a poor eye healthcare system in Ethiopia.
Rates of combined trachomatous and non-trachomatous CO in a population-based rapid assessment of avoidable blindness survey in Egypt indicated 33% CO,37 this result was greater than the current finding. The difference in the study’s outcomes may be attributed to the difference in the age of the participants. A study conducted in Egypt included individuals aged 50 years or older because this study demonstrated that the older the participants were, the greater the incidence of CO.
In the present study, advanced age was significantly associated with the prevalence of CO. Individuals aged 49–60 years and 61 years or older were approximately two times more likely to have CO than participants aged 18–34 years. This finding was similar to the study outcomes done in Australia,31 China,8 India,39 Iran12 24 and Nigeria.26 These findings may be related to an increase in age-related degenerative corneal conditions40 and an increase in ophthalmic operations41 in older adults.
In this study, the odds of CO were 2.7 times greater among the study participants who could not read or write than among the study participants who attended school and/or had a higher level of education. The results of previous studies conducted in India,39 China42 and Nigeria26 support these findings. Additionally, the TGES reported that having a high school education reduced the odds of CO by at least 30%.24 However, another study conducted in Iran showed that educational status was not related to CO.12 The authors hypothesise that the disparity in the study’s outcome between educational status and the prevalence of CO may be because being illiterate may decrease the level of knowledge on prevention, protective measures and where to access eye healthcare services whenever individuals are sick. However, educated participants may seek early intervention to address their condition before CO occurs.
The current study indicated that the odds of having CO were two times and five times greater among owners with middle-income and poor-income levels, respectively, than among rich participants. This means that the poorer the participant is, the greater the occurrence of CO. In this study, the odds of CO were at least 70% lower among housewives and students than among the employed participants. This may be because of the work conditions that are relatively safe and because of the low exposure to trauma and UV light. In addition, we assume that women and students may receive treatment earlier through community screening for trachoma before the condition occurs because they are the frontline vulnerable group for trachoma and may receive treatment as soon as the cause of CO occurs.
In general, the results of this study revealed the occurrence of a substantial burden of CO among the study population, implying that there are conditions that cause CO that have yet to be prevented, provided that the related socioeconomic impacts on the study population are reduced. This study provides useful evidence regarding factors associated with CO so interventions should consider the factors revealed to improve the quality of life of the affected individuals in the study population. After reviewing the findings on the prevalence and associated factors revealed by this study, the authors recommend that researchers carry out further studies to identify the causes of CO in the study area.
This research is the first of its kind in the study area, and since research on this topic is very limited, it has strong potential to provide recent information on the theme in the study area. This study’s findings are limited in that it did not report the causes or the related visual impairment and failed to state the grade of CO.