Vision is among the most vital senses of humans, which utilizes over 30% of the brain’s capacity for processing information (1). Consequently, the fear of vision loss ranks the highest among all possible disabilities (1, 2). Cataracts are the leading cause of curable blindness worldwide (3). According to the World Health Organization (WHO), as of 20121, there are an estimated 2.2 billion individuals living with near or distant visual impairment (4). Approximately 1 billion people suffer from moderate or severe distance visual impairment, with almost 94 million diagnosed with cataracts (4). Cataracts were responsible for 45% of global blindness in 2020 (4–6). In addition, cataracts are recognized as the second most common cause of moderate and severe vision impairment (MSVI) (7).

Cataracts may be congenital, secondary to trauma, or drug-induced, but the most common presentation is as age-related disease (3). Age-associated cataracts are mainly caused by the opacification of the lens due to oxidative damage (3). This form of blindness is associated with considerable disability and excess mortality, hampering the social and economic growth of the individual (8). Surgery is the most successful and least complicated treatment, leading to direct improvements in visual acuity and activities of daily living (ADL) along with decreased cataract-related morbidity and mortality (3). However, the distribution of cataracts is grossly uneven in low- and middle-income countries (LMICs) compared to high-income countries (HICs), with LMICs contributing 90% and HICs contributing 50% of all blindness (1, 8). LMICs contribute 90% of disability-adjusted life years (DALYs) due to cataracts, thus creating gross inequalities in the burden of cataracts (8).

More than 90% of individuals with visual impairment caused by cataracts live in LMICs (9–13). The prevalence of cataracts is increasing among LMICs, attributed to their rapid ageing population (8). For instance, data from India's 2011 census indicated that the proportion of individuals aged 60 years and above was around 8.6% of the total population (14). This percentage has been consistently on the rise due to declining birth rates and advancements in healthcare, contributing to extended life expectancy. Projections suggest that this demographics will further increase to 19.5% of the total population, reaching approximately 319 million by 2050 (15). More than half of the people experiencing blindness due to cataracts remain unreported due to lack of medical facilities in the vicinity, higher cost, gender bias, lack of awareness about available treatments, and fear of surgery (15). Effects of cataracts are not only confined to visual deficit but also to functional and psychological disability, which significantly reduces health-related quality of life (HRQoL) (16). India was the first country to start a blindness control programme in the world with the National Programme for Control of Blindness and Visual Impairment in 1976. The programme aimed to reduce blindness and visual impairment through various interventions, including medical treatment, surgeries, and awareness campaigns. It is worth noting that the specific types of cataract surgeries performed under this programme include manual small incision cataract surgery (MSICS) and phacoemulsification. According to the National Blind Visual Impairment Survey 2019, the coverage for cataract surgery among blind individuals and visually impaired people was 93.2% and 74.0% in India, respectively (17). As India has one of the oldest blindness control programmes, it is pertinent to determine the factors associated with undergoing cataract surgery and compare them with those who did not opt for corrective surgery. The evidence generated can further help reduce the unmet needs for cataract surgery by informing existing programmes and guiding future policies. Hence, this study was conducted with the objective of estimating the prevalence of cataracts among adults aged ≥50 years in India using data from the Longitudinal Aging Study in India (LASI), wave-1. Further, we compared the determinants of undergoing cataract surgery and the unmet needs for cataract surgery among older adults in India.

The average age of the participants was 63.4 ± 9.57 years, ranging from 50 to 116 years. Most participants (63.16%) belonged to the 50–65 year category. Almost half of the participants (53.29%) were women. Almost two-thirds of the population resided in rural areas. The detailed socio-demographic characteristics of the study population are presented in Table 1. The gender-wise stratified socio-demographic characteristics of the study population are presented in Supplementary Table S1.

People aged 50 years and above represent around 13% of the total Indian population (14). This study provides novel insights into the prevalence of cataracts, coverage of cataract surgery, and unmet needs among a nationally representative sample of participants aged 50 years and above, which is important for the programme. We observed a high coverage of cataract surgery and a lower unmet need among the study participants.

Age-related cataracts are the leading cause of visual impairment and blindness, requiring timely intervention in the form of surgery (19). Our analysis reveals that participants aged 66–80 years had a higher prevalence of cataract surgery, followed by respondents aged >80 years. Our findings are consistent with the results of a similar study conducted among a representative Finnish population, which showed a relatively higher coverage of cataract surgery with increasing age (20). The proportion of unmet surgical need, however, was greater (39.1%) in previous geriatric population studies carried out by Wasekar and Lavangare in Mumbai and Vimalraj et al. in Kerala (21, 22). Moreover, shorter operating times, availability of more efficient anaesthesia, and a trend of daycare surgery have made cataract surgery a minor surgical procedure. Nonetheless, we observed that participants aged 50–65 years had the highest unmet needs for cataract surgery. A probable reason for this could be that people in this age group do not seek medical intervention until the disease progresses to an advanced stage. Although there were variations in the coverage of cataract surgery and unmet needs, no significant difference was observed between the age groups in both categories. This reflects the awareness among the masses, which has been a cumulative effect of the ongoing blindness control programme.

We observed that women had a higher coverage and lower unmet needs for cataract surgery. However, our findings contradict previous reports that show a lower coverage of cataract surgery among women (20–25). Nonetheless, our findings do not show a significant association between gender and outcome variables. Interestingly, no significant association was observed across urban and rural residents in accessing cataract surgery. In addition, contrary to prior studies, we found that rural residents had higher coverage and fewer unmet needs for cataract surgery than urban residents (26). However, multiple barriers contribute to urban–rural disparities in accessing healthcare facilities, including lack of financial resources, availability of healthcare setups, geographical location, unavailability of human resources, and civic amenities (15, 27). Still, a higher coverage indicates the strength of India's existing National Programme for Control of Blindness, which aims to prevent visual disability by providing free camps with free diagnostics and treatment services for cataract surgery. The various steps taken to reduce the burden of unmet need for cataract surgery include organization of mass surgery camps and awareness campaigns through various Information, Education, and Communication (IEC) activities in the community. In addition, the decentralization of government healthcare facilities, along with recent efforts to strengthen primary care by establishing Health and Wellness Centres, has helped in reducing this disparity (27). Similar findings were reported by Nathenetel et al. and Madaki et al. in Nigeria, where cataract surgery coverage showed a slight improvement (28, 29).

Individuals with no formal education and those who never worked had a higher coverage of cataract surgery. This further strengthens our notion that the existing programme has been successful in reaching each stratum of society. However, we observed a significant association between unmet needs for cataract surgery and the most deprived quintile. This is consistent with the findings of another study, which showed a higher risk of developing cataracts among the most deprived people (20). This might be due to a lack of awareness, inability to pay, or other socio-cultural factors, which further need to be explored. To achieve the global WHO target of increasing coverage of cataract surgery by 30% by 2030 and achieving universal health coverage, the most disadvantaged group must also have egalitarian access to healthcare facilities (25).

Participants belonging to the west, north, and south regions were significantly associated with having cataract surgery, while no significant association for unmet needs for cataract surgery was observed. This points towards replicating the best practices adopted by these regions in other regions to achieve zero blindness. In addition, socio-cultural factors of patients, their health systems, and awareness play an important role in this uptake, which needs to be explored further. Moreover, a probable reason for the central and north-eastern zones to have fewer cataract surgeries may be due to disparities in health infrastructure, geographic remoteness, and differences among the participants studied, which can also impede access challenges (31, 32). Moreover, health-seeking behaviour also varies between the regions, which could also be a probable reason for this difference (33). An Iranian study also found that cataract surgery coverage is low due to low cost and other resources (30).

Although there is a considerable burden of age-related cataracts in India, the coverage of cataract surgery is high. Nonetheless, the unmet needs for cataract surgery cannot be overlooked. The existing blindness control programme has contributed significantly to increasing the coverage of cataract surgery, but it still needs to be strengthened, especially to reach the most deprived sections of society. In addition, efforts to increase awareness should be continued, and regional differences should be managed by adopting the best practices of areas with higher coverage of corrective surgery.