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Ophthalmology
Original research
Retrospective analysis of cataract surgery outcomes in China from 2009 to 2018: from a national registry system data
  1. Jingjing Feng1,
  2. Catherine Jan2,3,
  3. Yaguang Peng4,
  4. Mingguang He5,
  5. Lei An1,
  6. Leilei Zhan1,
  7. Wei Shi6,
  8. Xiaoxia Peng4,
  9. Wenhan Shang1,
  10. Wei Li1,
  11. Xiao Xu7,
  12. Li Yao1
  1. 1Department of Nursing Administration and Rehabilitation Research, National Institute of Hospital Administration, Beijing, China
  2. 2Lost Child’s Vision Project, Sydney, New South Wales, Australia
  3. 3Centre for Eye Research Australia, Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
  4. 4Center for Clinical Epidemiology and Evidence-based Medicine, Beijing Children’s Hospital, Beijing, China
  5. 5State Key Laboratory of Ophthalmology, Sun Yat-Sen University Zhongshan Ophthalmic Center, Guangzhou, China
  6. 6Department of Ophthalmology, Beijing Children’s Hospital, Capital Medical University, Beijing, China
  7. 7Department of Healthcare Service and Safety Research, National Institute of Hospital Administration, Beijing, China
  1. Correspondence to Dr Xiao Xu; po_niha{at}163.com

Abstract

Objective To evaluate patients’ benefits after cataract surgery and to form recommendations for Chinese national health policy decision makers and administration departments based on the quality of cataract treatments.

Method An observational study based on real-world data source from the National Cataract Recovery Surgery Information Registration and Reporting System.

Results A total of 14 157 463 original records were reported from 1 July 2009 to 31 December 2018. The factors that influenced the 3-day postsurgical best-corrected visual acuity (BCVA), the primary outcome, were analysed by logistic regression analysis. We found that a history of hypertension (OR=0.916) or diabetes (OR=0.912), presurgical pupil abnormality (OR=0.571) and high intraocular pressure (OR=0.578) were harmful to the postsurgical BCVA improvement (BCVA ≥6/20), while male sex (OR=1.113), better presurgical BCVA level (OR=5.996 for ≥6/12–<6/7.5 and OR=2.610 for >6/60–<6/12 taken ≤6/60 as reference), age-related cataract (OR=1.825) and intraocular lens implantation (OR=1.886) were statistically beneficial to the postsurgical BCVA improvement. Compared with extracapsular cataract extraction (ECCE) with large incision, the ECCE with small incision (OR value=1.810) and the phacoemulsification (OR=1.420) significantly improved the benefit probability.

Conclusion ECCE with small incision has comparable effects on postsurgical BCVA improvement of phacoemulsification. Therefore, ECCE could be an alternative cataract surgical treatment in economically underdeveloped areas in China, provided the surgeons are adequately trained.

  • EPIDEMIOLOGY
  • Health policy
  • Cataract and refractive surgery

Data availability statement

Data are available upon reasonable request. Data are available upon reasonable request and need to contact the corresponding authors.

http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

https://doi.org/10.1136/bmjopen-2022-070989

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    STRENGTHS AND LIMITATIONS OF THIS STUDY

    • A real-world study to evaluate the outcome of the cataract surgery in China from a national platform.

    • Huge sample size spanning 9 years of real-world data.

    • Data reported by hospitals is not mandatory and might lead to omission.

    • Missing outcome of the cataract surgery limited the analysis of the mid-term outcome assessment.

    • Case-based data structure failed to analyse the repeated patients and the severity of cataract.

    Cataract remains the most common cause of blindness worldwide, especially in developing countries, including China.1–3 Surgical treatment, including traditional extracapsular cataract extraction (ECCE), phacoemulsification and femtosecond laser-assisted surgery, can effectively remove cataract-induced visual impairment and improve patients' quality of life.4–6 The World Health Organization (WHO) recommended that poor best-corrected visual acuity (BCVA < 6/60) or borderline (BCVA < 6/18) outcomes after cataract surgery should not be more than 10% to 20%.6 7 Several studies indicated the percentage differs from region to region, from population to population.8–14 More importantly, the quantity of surgery is increasing rapidly,15 but patients' benefits need to be evaluated in the light of the quality of health technology advancement. We know little about quality of surgery in China. At a national level, cataract treatment services providers should improve their overall quality to benefit more patients and medical institutions. Simultaneously, national health policy decision makers and administration departments should consider how to guide stakeholders to improve the quality of cataract treatments.

    The primary purpose of this study was to assess the effect of cataract surgery based on an electronically registered record system, providing insights for future policy direction on cataract-related health service provision for developing countries.

    Methods

    Electronically registered report system and data source

    The data source of this study originated from the National Cataract Recovery Surgery Information Registration and Reporting System, www.moheyes.com (accessed on 11 February 2023). This database was developed by the National Institution of Hospital Administration, to comprehensively evaluate the situation of cataract surgery outcomes and increase the rate of cataract surgery (CSR) per million population in China. The General Office of the former Ministry of Health of the People’s Republic of China issued the ‘Notice on the Activation of the National Cataract Recovery Surgery Information Registration and Reporting System’ in 2009.16 According to this recommendation document, from 1 July 2009, all patients receiving any cataract surgery in medical services and institutions nationwide should have registered and reported online on this system within 4 days after surgery by doctors. Registry and report were not mandatory, but the data standardisation of the system was emphasised by the national health administrative department. The latter oversaw the management and supervision of the electronic system application level by level, providing authorisation to institutions, organising the training and guidance to personnel and inspecting the registered reporting.

    Study design and ethics

    We planned to analyse the factors influencing the cataract surgery outcome through a retrospective case–control study design using real-world data. This study analysed the data originated from the system above, from 1 July 2009 to 31 December 2018. We applied and were granted ethical approval for the study plan, data management plan and an exemption of informed consent for using existing data.

    Participant and public involvement

    No participants were involved in setting the investigation or the outcome measures for the present study, nor were they asked to advise on the interpretation or the writing up of this study.

    Data collection and data processing

    The data and information used include: (1) medical institution settings, such as hospital name, address, level and administration affiliation category. In China, medical institutions’ administration affiliation included the following categories: provincial, municipal, county, township and others (military and private); (2) clinical characteristics of patients, including sex, age, diagnosis, medical history, source of surgical funds; (3) presurgical examinations of the cataract-operated eyes, including uncorrected visual acuity (UCVA), BCVA, intraocular pressure, pupil status, type of cataract; (4) surgical information, including intraocular lens implantation, intraoperative complication and (5) postsurgical visual status (UCVA and BCVA 3 days and 3 months after cataract surgery) and the occurrence of postsurgical complications. The detailed case-report form is listed in online supplemental table 1. Each cataract surgery case, not the patient, was reported on the system. Sensitivity analysis for bilateral cataract patients was not performed because all the identifiable information had been removed to protect the patient’s privacy.

    Considering the potential bias, a sensitivity analysis was conducted by data imputation for the missing values of 3-day postsurgical BCVA, which were assumed as unimprovement. Figure 1 shows the flowchart of analysis data sample size obtained from the system. The patients’ age distribution was divided into six age groups, namely ≤40 years, 41–50 years, 51–60 years, 61–70 years, 71–80 years and >80 years. Visual acuity was measured using a logarithm of the minimum angle of resolution number chart at 6 metres. The cataract was categorised into five types according to the clinical diagnosis from the recording system, including age-related, congenital, traumatic, complicated cataract and others. Intraocular pressure was measured by an ophthalmologist using a non-contract tonometer before surgery, and over 20 mm Hg15 was defined as abnormal presurgical intraocular pressure. Presurgical pupil abnormalities were grouped according to the examination before surgery, such as pupil adhesion. Four surgery patterns were included in the study, including ECCE with large incision (relatively exceeding the conventional incision length was classified as large incision), ECCE with small incision (conventional surgical incision was defined as 5.5–6.0 mm), phacoemulsification and others (failed to categorise clearly into the former three patterns in the system). The 3-day postsurgical complications were different from those of 3-month after surgery. The former mainly included leaking or ruptured incision, endophthalmitis, intraocular lens deviation, corneal oedema, anterior chamber haemorrhage, iris injury, iritis, vitreous haemorrhage and suprachoroidal haemorrhage. 3-Month postsurgical complications included opacity of the posterior lens capsule, bullous keratopathy, cystoid macular oedema, retinal detachment, endophthalmitis, intraocular lens deviation, iridocyclitis and secondary glaucoma.

    Figure 1
    Figure 1

    The flowchart of analysis data sample size obtained from the National Cataract Recovery Surgery Information Registration and Reporting System. BCVA, best-corrected visual acuity.

    Postsurgical visual status outcomes

    The primary outcome, that is, the effect of surgery, was defined as the improved visual status of 3-day postsurgical BCVA ≥6/18 for the cataract-treated eye, according to the WHO recommendation. While the 3-month postsurgical BCVA was a mid-term secondary outcome. The postsurgical BCVA was dichotomised into improved and unimproved BCVA ≥6/18 and <6/18.

    Statistical analysis

    Mean±SD was used to describe data with normal distribution, while median and interquartile range (IQR) was used for skewed data. Differences between groups were compared and tested using t-test or Wilcoxon’s signed-rank test determined by the distribution of the continuous variables. χ2 test was used to assess differences among groups for dichotomous variables. When observing the change in tendency among groups, a trend test was also performed. Binary logistic regression analysis was performed to explore the factors of surgical therapeutical effects, which dichotomised into improved (BCVA ≥6/18) and unimproved (BCVA <6/18) outcomes, as the dependent variable referred above. Postsurgical BCVA improvement was defined as the event of the dependent variables in the logistic model. The dummy variables were set for multinomial factors in the model. Age, sex, presurgical visual acuity, hypertension and diabetes history were adjusted into the model, and all independent variables were entered by a stepwise method with the p value criteria at 0.1 for both the selected entry and selected stay. Nomogram was applied to present the logistic results graphically using rms package in R software (V.3.6.3, https://www.r-project.org/). Area under Receiver Operating Characteristic (ROC) curve and C index were used to evaluate the accuracy of the prediction effects. Statistical analyses were also performed using SAS V.9.4. Statistical significance was defined as p<0.05.

    Results

    Data overview

    Till the end of 2018, a total of 14 157 463 original records were reported from 3351 medical institutions nationwide. The amount of phacoemulsification surgery increased annually, while the number of ECCE with small incision decreased. The number of records and the distribution of surgery patterns in each year are shown in online supplemental table 2. The missing rates of the pivotal variables included presurgical, postsurgical 3-day and 3-month BCVA and presurgical intraocular pressure were 29.7%, 44.1%, 80.6% and 0.3%, respectively.

    The mean age of the cases was 69.7 years old, and 69% concentrated in the 61–80 years old. Female accounted for 58.0%. Medical history of hypertension and diabetes was present in 15.4% and 8.3%, respectively. The proportion of presurgical high intraocular pressure was 6.3%, and the proportion of abnormal pupil was 1.0%; 79.9% of surgery was phacoemulsification, and 97.7% received intraocular lens implantation. Considering the administration affiliation of medical institutions, the data reported from provincial, municipal and county medical institutions were 18.6%, 47.3% and 32.1%, respectively. Postsurgical 3 days and 3 months complications were 3.5% and 1.4%. See table 1 for details.

    View this table:
    Table 1

    The characteristics of the reported cataract surgery cases in the reporting system from 2009 to 2018

    Presurgical and postsurgical visual acuity

    The poor postsurgical BCVA rates were 1.7% in 3-day and 1.1% in 3-month. And the borderline rates were 8.9% in 3-day and 6.2% in 3-month. Figure 2 depicted the changes of BCVA from presurgery to postsurgery and the distribution at each measurement time listed in online supplemental table 3. According to presurgical BCVA level stratification, the changes between BCVA presurgery and postsurgery (postsurgical minus presurgical value) were compared. For those with presurgery BCVA worse than 6/7.5, the median difference of BCVA of 3-day postsurgery and presurgery was positive, ranged 0.1–0.45 in decimal values, which indicated improvement in visual acuity after cataract surgery. For those with presurgery BCVA better than 6/7.5, an invalid difference occurred, that is, the median difference between postsurgery and presurgery was zero or negative, suggesting that visual acuity remained the same or got worse after cataract surgery. A similar trend was observed for the median difference of BCVA for 3-month postsurgery and presurgery (online supplemental table 4 and figure 2). These differences were statistically significant.

    Figure 2
    Figure 2

    The boxplots of the BCVA changes between presurgery and postsurgery. BCVA, best-corrected visual acuity.

    Factors defining postsurgical outcomes

    The proportion of males in the improved group was larger, and the average age was younger, compared with the unimproved group. The prevalence of hypertension and diabetes was lower in the improved group. The composition proportion of the presurgical BCVA level was slightly different between the two groups. The median presurgical intraocular pressure was at the same level in both groups, but the gap between the quartile was significant in the unimproved group. In addition, cataract types, surgery patterns, intraocular lens implantation, and the administration affiliation of hospitals were similar between the two groups. The incidence of intraoperative complications and postsurgical complications were both higher in the unimproved group (table 2).

    View this table:
    Table 2

    The comparison of characteristics between BCVA improvement and unimprovement

    Multivariate analysis of postsurgical outcomes

    The independent variables included sex, age, hospital administration affiliation, presurgical BCVA, pupil status, intraocular pressure, medication history of hypertension or diabetes, cataract type, surgery pattern, intraocular lens implantation and postsurgical complications occurrence. The variable values, including dummy settings, are listed in online supplemental table 5. The binary logistic regression model was visualised in figure 3 and the parameters of the model were listed in table 3. Compared with those aged over 80 years old, it appeared that those aged 61–70 years benefited most from the surgeries, with an OR value of 1.963 (95% CI 1.944 to 1.982). Presurgical intraocular pressure abnormality (OR=0.578) and pupillary state abnormality (OR=0.571) reduced the probability of benefit by 50%. The benefits of those with hypertension (OR=0.916) or diabetes (OR=0.912) were also reduced by 9%. It is worth noting that compared with the ECCE with large incision, the benefit/improvement by ECCE with small incision was significantly increased by 65.8% and those of phacoemulsification by 30.7%. The results of 3-month outcomes were given in online supplemental table 6. In addition, it seemed the missing values had little influence on the results through a sensitivity analysis (see online supplemental tables 7 and 8).

    View this table:
    Table 3

    The binary logistic regression analysis for the 3-day postsurgery BCVA improvement

    Figure 3
    Figure 3

    The forest plot of the binary logistic regression model for 3-day postsurgery vision improvement (3-day postsurgery BCVA ≥6/18). BCVA, best-corrected visual acuity; ECCE, extracapsular cataract extraction.

    Prediction of postsurgical BCVA improvement

    A prediction model for 3-day postsurgical BCVA improvement was constructed. Nomograph visually depicted that hypertension and diabetes history and presurgical conditions, including BCVA, intraocular pressure and pupil were the most important factors in surgery outcome (figure 4). Male and young age were associated with the outcome as well. The C index of the model was 0.694 and the calibration curve was depicted in online supplemental figure 1.

    Figure 4
    Figure 4

    The nomograph for the 3-day postsurgery BCVA improvement based on binary logistic regression model. BCVA, best-corrected visual acuity; ECCE, extracapsular cataract extraction; IOL, intraocular lens implantation.

    Discussion

    Cataract remains the primary cause of blindness and visual impairment for people aged 50 years and older in China, constituting up to 35% of cases of blindness and 67.1% of cases of visual impairment, respectively.17–20 The prevalence of cataract has decreased recently with the advancement of cataract surgical technology from suppliers and increased visual demand from patients.1 The CSR per million people per year has been continuously improved in China, from about 83 in 1988 to 2205 in 2017,21 an increase of nearly 27 times. The CSR target proposed in the ‘13th 5-Year National Eye Health Plan (2016–2020)’22 has been achieved ahead of schedule. This means that the gap between China and the developed countries is narrowing.

    This study showed improved outcomes in both the short-term 3-day postsurgical BCVA and the medium-term 3-month postsurgical BCVA. These trends of improved BCVA were also observed among all hospital administration affiliations (see online supplemental table 3). According to presurgical BCVA data reported from the hospital administration affiliation, the sum of the distribution proportion of presurgical BCVA groups for municipal and county-affiliated hospitals reached over 75%. It was noteworthy that the proportion of cases with a presurgical BCVA over 6/7.5 accounted for more than 60% in municipal medical institutions. These results suggested that the quantity of performed surgery in primary level hospitals, such as county-affiliated hospitals, would play a significant role in improving CSR.

    It could be seen that the cases with poor presurgical baseline BCVA had significant improvement. Figure 2 directly showed that the postsurgical BCVA improvement was not ideal in cases whose presurgical BCVA ≥6/7.5 (the median changes in BCVA were 0 and −0.2 in decimal format, respectively, online supplemental table 4). For the subgroups of presurgical BCVA ≥6/12–<6/7.5 and >6/60–<6/12, the visual acuity improvement range was basically the same at 3 days after and 3 months after operation, and the improvement here was greater than that with presurgical BCVA ≥6/7.5. The most improved subgroup was those with presurgical BCVA ≤6/60, and the improvement values are 0.45 and 0.55 in decimal format respectively (online supplemental table 4). For patients who already had reasonably good vision before the surgery, the room of improvement is small. The surgical benefit for these patients with better presurgical BCVA might be reflected in the improvement other than just visual acuity, such as the comfort of seeing, which need to be confirmed in further well-design studies.

    The results of the multivariable analysis in this study indicated that female patients, older than 80 years, with a history of diabetes mellitus or hypertension, presurgical abnormality of the pupil and presurgical high intraocular pressure were most at risk of having negative outcome from cataract surgery. This is consistent with published studies worldwide.7 9 12 The sex gap might not be due to biological or physiological factors, but more likely due to social factors, such as women’s role, especially middle-aged and older women, in family life and their tolerance to disease. Women tend to reach a relatively severe stage of impaired vision before seeking treatment.12 In our large sample, there were more female (48% proportion of the whole cases) than male (35%) with the lower presurgical BCVA, ≤6/15. It seemed the influence of age on postsurgical BCVA improvement was not monotonous. Especially the elderly (aged over 80 years) with the higher risk for surgery treatment, comorbidity with cardiovascular, respiratory diseases or metabolic diseases, did not have an improved postsurgical BCVA, and were more vulnerable to an unsatisfied outcome, compared with the younger groups. Studies pointed out that fundus artery lesions caused by diabetes and hypertension could impact the lens’s nutrient metabolism, thus affecting the surgery outcomes.12 23 Aligned with previous studies,24 25 our results also showed that high presurgical intraocular pressure and pupil abnormality halved the ideal therapeutic effect of postsurgical BCVA improvement. Our results also illustrated that the worse the baseline BCVA was, the more likely it was to improve after surgical treatment. However, under the premise of prevention principle, for cataract patients with BCVA ≥6/7.5, immediate cataract surgery intervention might be arbitrary, the clinical features and indications of the patients should be cautiously considered and reasonably evaluated, such as visual comfort, of the patients, and not be based on BCVA alone. Our study suggested that appropriate presurgical ocular clinical features are essential to achieve ideal surgical outcomes. In addition, for cataract patients with other ocular diseases, such as potential pupil diseases and pathological conditions causing elevated intraocular pressure, reasonable surgical risk and prognosis should be evaluated based on clinical practice before surgical treatment, to maximise the benefits for patients.

    Even though the number of surgeries has been increasing annually, the number of ECCE has shrunk, as there has been a continual increase of phacoemulsification cases that has been replacing other forms of cataract surgery. Studies had verified that the smaller the corneal incision, the smaller the corneal astigmatism affecting the postsurgical vision recovery, which would be beneficial to vision recovery.26 Our study showed, regarding ECCE with large incision taken as a reference, the postsurgical BCVA improvement effects of both phacoemulsification (OR=1.420) and ECCE with small incision (OR=1.810) were very satisfactory. However, with the reference to phacoemulsification gave a result of OR=1.275 for ECCE with small incision. This is probably due to the effect of phacoemulsification, which is comparable to that of ECCE with small incision surgery, and had an even higher possibility of BCVA improvement. The adoption of phacoemulsification required high cost, advanced medical equipment and specialised training. On the other hand, ECCE with small incision cataract surgery had the advantage of lower cost and reliable efficacy; however, it is also dependent on the surgeon’s experience and skills, and therefore can be prone to complications if done by an inexperienced surgeon.24

    Another interesting finding was provincial medical institutions achieved not the highest probability of postsurgical BCVA improvement by surprise. In comparison, municipal and county-level hospitals accounted for the largest quantity of cataract surgeries, with overall ideal outcomes with OR 1.195 and 1.426 respectively, for postsurgical BCVA improvement. Due to the fact that patients with the more complicated conditions tend to attend provincial medical hospitals for cataract surgery. On the other hand, the implementation of various cataract alleviation projects under the government’s guidance and support may have also contributed to the surgery quality at the primary level (municipal and county-level). This continuous support over several decades, including poverty alleviation projects and training programmes for eye care professionals, have improved cataract treatment at the primary level.15 The critical elements of cataract prevention work in China at the present stage mainly include15: (1) the quantity and quality of cataract surgery to be urgently improved; (2) primary ophthalmology capacity needs to be promptly strengthened; (3) resources from high-level hospitals to be used to support the development of ophthalmology in primary hospitals effectively; (4) medical security to be strengthened and treatment costs to be reduced. For the ophthalmic medical institutions at the primary level (municipal and county-level), the continuous increase in the number of cataract surgery was not the only goal. The other equally important goal was to improve the procedure’s quality to ensure maximum benefit for the patients.27 In the past, concerns about surgical quality affected CSR, especially in underdeveloped regions or areas. They also severely influenced the recognition and acceptance of cataract surgery for cataract patients.28 29 Moreover, the government’s health administration department should also make appropriate decisions for local cataract treatment according to different population characteristics and economic development level at the primary level. That is to say, not all primary hospitals must develop phacoemulsification surgery. ECCE with small incision can be recommended as an alternative to phacoemulsification wherever the requisite equipment and expertise for phacoemulsification are unavailable.30 It would also be possible to enhance personnel training and improve doctors’ surgical skills in order to develop other procedures with more health and economic benefits. Compared with capital expansion relying on equipment and devices, it is particularly valuable for developing countries to improve the efficiency of cataract surgery by achieving technological breakthroughs through talent cultivation.

    This study gave a frame of the cataract surgery outcomes and benefits for patients in China during the last decade. The sample size was big, spanning 9 years of reported data. However, there were some limitations in the study design and data mining process. The first methodological limitation was that we only used data-based analysis rather than a prospective cohort study with de novo design, resulting in relatively insufficient evidence grade. Clinical trials or cohort studies are needed to further verify our results. Second, the data from the system were self-reported from medical institutions through the network, and the reporting was done on a voluntary basis. The underreporting was a bigger headache. The compliance of follow-up revisiting depended on the effect of the surgery. The missing revisiting was most likely to occur in the cases that got a better self-feeling recovery of the postsurgical BCVA. Additionally, the longer the follow-up period, the more likely it is to have compliance issues for follow-up. This represented one of the potential reasons for the missing of 3-day postsurgical BCVA and the fewer outcomes of 3-month postsurgical BCVA. Taken 3-day postsurgical BCVA for instance, comparing groups between cases with missing 3-day postsurgical BCVA values and missing-free cases, there were more intraoperative complications (5.2% vs 1.4%) and postsurgical complications (4.9% vs 1.3%) reported in missing-free cases group (see online supplemental table 8). This might reflect a subconsciousness of patients’ attention to outcomes that ‘No better effects matter’. Similar results of the 3-month outcomes and the sensitivity analysis were observed respectively (see online supplemental tables 6 and 7). After the primary outcomes data imputation, all missing values of 3-day postsurgical BCVA were assumed as non-improvement, the factors in the logistic model showed a similar OR compared with the results using real outcomes with missing values. A recent study reported early vision assessment for all patients and follow-up assessment only for patients who return to the clinic without prompting.27 It would have been likely to obtain a more conservative result because many cases with postsurgical BCVA improvement might have been omitted in the analysis due to a lack of follow-up revisiting. Finally, the number of surgical cases was reported in the system, and the analysis was case-based. Due to the data structure, there was no matching of the patient and the affected eyes, not considering the repeated patients during the decade, which might lead to some collinearity when using model analysis.

    In conclusion, the number of cataract surgeries has been increasing annually in the last decade in China, especially in municipal and county-level medical institutions. Appropriate presurgical ocular clinical features are essential to achieve ideal surgical outcomes. For cataract patients with other ocular diseases, such as potential pupil diseases and pathological conditions causing elevated intraocular pressure, reasonable surgical risk and prognosis should be evaluated based on clinical practice before surgical treatment, to maximise the benefits for patients. In addition, ECCE with small incision and phacoemulsification had a comparable effect on postsurgical BCVA improvement. Health administration departments need to develop accurate cataract treatment strategies according to the resource endowment of different primary hospitals among areas, to guide primary medical institutions to develop cataract surgery. The final aim is to increase CSR further while improving the benefits for the patients.

    Data availability statement

    Data are available upon reasonable request. Data are available upon reasonable request and need to contact the corresponding authors.

    Ethics statements

    Patient consent for publication

    Ethics approval

    The approval was provided by the Ethics Committee of the National Institution of Hospital Administration in China (Ethics No. 1015).

    Acknowledgments

    The preprint of the study could refer as JF and YP and Zhang, Haiyan and MH and LA and LZ and Han, Xiaotong and WL and XP and WS and WL and XX and LY, Device-Dependent Medical Intervention is Not a Panacea: Analysis of Cataract Surgery Outcomes in China from 2009 to 2018 Based on Data From the National Cataract Recovery Surgery Information Registration and Reporting System. Available at SSRN: https://ssrn.com/abstract=3788919 or http://dx.doi.org/10.2139/ssrn.3788919

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    Supplementary materials

    • Supplementary Data

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    Footnotes

    • XX and LY contributed equally.

    • Contributors JF contributed to the data collection and cleaning, the data analysis, and drafted the manuscript, review and revision of the manuscript. CJ contributed to review of the scientific literature, and review and revision of the manuscript. YP contributed to perform the data analysis, quality control of the statistics, review and revision of the manuscript. MH contributed to data interpretation, review and revision of the manuscript. LA and LZ contributed to the design of the registration and reporting system, and quality control of the data collection and management. WShi and XP contributed to data interpretation, review and revision of the manuscript. WSha and WL contributed to review of the scientific literature, review and revision of the manuscript. XX contributed to conceive the study and project management, the design of the registration and reporting system, quality control of the data collection and management, review and revision of the manuscript. LY contributed to the project design, quality control of the data management, review of the scientific literature, review of the manuscript. XX and LY were responsible for the overall content as the guarantor.

    • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

    • Competing interests None declared.

    • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.