The CSR increased from 6074 cases per one million population in 2012 to 7134 cases per one million population in 2016, indicating a more than 15% growth in the CSR after HTP implementation. Although the overall CSR following HTP is high compared to several studies [12, 26], it is still low in comparison with countries like the USA [15], France [16], and Japan [26], which should receive prompt attention due to population ageing. An increase of about 10% in CSR has been reported from the US and France [3]. Although population ageing and increased demand for cataract surgery are effective in this regard, the CSR increased by about 25% in 2016 compared to 2012, which is not proportionate to the trend of population growth.
In 2012, the proportion of cataract surgery in private and governmental centers was almost similar (46.14 vs. 42.27) while it increased to 58.69% in governmental centers (22% increase) and reduced to 32.70% in private centers (18% reduction) in 2016.
A previous report from Iran showed that the proportion of cataract surgery was decreasing in governmental centers and increasing in private centers during 2006–2010 [27]. These findings clearly indicate that HTP implementation resulted in a marked increase in the proportion of cataract surgeries in governmental centers. It seems that in private centers, the supply and demand is a function of GDP, and the percentage of the rich reduced slightly due to GDP reduction.
An interesting finding was a reduction in the proportion of cataract surgeries in charity (15%) and insurance (25%) centers. Reduced GDP has a direct correlation with reduced insurance support [28]. Peleckienė et al. [28] reported a similar finding in European countries. In the present study, a 33% reduction of GDP was associated with a 25% decrease in the proportion of cataract surgeries in insurance centers. It seems that due to the higher franchise of HTP in terms of surgical costs compared to insurances or even charity centers, a large proportion of patients preferred to undergo cataract surgery in governmental centers. A CSR of 10,000 was reported from US in 2011 with a GDP of about 50,000$ [12], while Iran’s GDP was 5253$ and CSR was 7479 in 2016 with a high percentage of cataract surgeries being financially taken care of by the government. In other words, the results showed that the financial support of HTP for cataract surgery in government centers compensated the decreasing trend of GDP.
The highest growth in CSR was observed in the 1st quartile followed by the 4th quartile. The number of cataract surgeries was smaller in provinces in the 1st quartile as poorer provinces due to the unavailability of eye care services (surgeon, IOL, surgical equipment) and poverty. However, the number of cataract surgeries increased markedly in these provinces after the HTP due to the government support for surgical costs. Hashemi et al. [29] also reported a lower CSR in poorer provinces. There are reports of economic inequity in cataract surgery and other eye care services in the literature [30]. It has even been shown that blindness and vision impairment are more prevalent in poorer populations with a high percentage of the difference between the poor and rich being due to the direct effect of the economic state [31, 32]. In other words, if blindness is considered an important outcome of leaving cataract untreated, a great part of the distribution of blindness is related to the economic state and inequity in the distribution of cataract surgical services between the 1st and 4th quartiles. After the 1st quartile, the largest growth in the CSR occurred in the 2nd quartile, which confirms the above.
Wang et al. [12] reported that surgical services were mostly offered by private centers and the patients pay for the services in high-income countries. Carvalho et al. [33] found that the highest concentration of ophthalmologists was in high-GDP areas in Brazil; therefore, part of CSR in private centers may be a function of GDP. Moreover, due to the high concentration of ophthalmologists in private centers, there is inequality in the distribution of cataract surgery, especially in economically weaker areas.
One of the HTP strategies was equity in the distribution of ophthalmologists, especially in the first 1st economic quartile.
This strategy was implemented to support the retention of physicians in underserved areas and the family physician program. In this part, health houses and centers were equipped and physician coverage increased to 100% in these areas. Therefore, the CSR changes were greatest in centers in the 1st and 4th quartiles for two reasons, including the financial support of HTP for cataract surgery, which encouraged low-income people to undergo surgery, and increased proportion of ophthalmologists in centers in quartile one compared to before HTP implementation.
As mentioned earlier, UCVA-BS decreased slightly in charity enters compared to other enters before HTP, while the worst UCVA-BS after HTP was seen in government centers. Moreover, the mean UCVA-BS reduced significantly in government centers. It should be noted that some countries have certain visual acuity cut points for cataract surgery [34]. However, a worse UCVA-BS after HTP in patients presenting to government centers indicates that subjects with cataract related vision impairment that could not afford surgery due to financial constraints, were on long waiting lists, and thus had lost their vision decided to undergo surgery after HTP. Other reasons may also explain this finding. First, people also sought treatment before HTP but the system could not respond to the high demand for treatment, and therefore people were on long waiting lists and lost their vision. Second, since access to treatment and surgery was facilitated after HTP, there was an increase in the demand for cataract surgery, resulting in vision loss in people on long waiting lists.
The results showed that UCVA-BS became worse in patients in the 1st and 2nd quartiles that presented for surgery after HTP.
In other words, the patients in these quartiles, as poor quartiles, waited long for surgery due to financial problems and lost their vision before HTP; however, a high percentage of them decided to undergo surgery after HTP resulting in a marked reduction in UCVA-BS after HTP. Since the data were analyzed two years after implementing the HTP, this finding indicates the immediate effect of HTP on vision impairment. Population-based studies in longer periods are required to evaluate the long-term effect of HTP on vision impairment in different populations to investigate the prevalence of vision impairment after HTP.
UCVA-BS improved slightly in private centers and high-income quartiles. It seems that the high percentage of patients presenting to governmental centers for surgery and reduced demand for surgery in private centers after HTP led to overtreatment in these patients; in other words, patients with a better visual acuity were received surgery in these centers.