Introduction

Cataracts, characterized by the clouding of the eye’s lens, can develop at any age and may lead to vision impairment. In different to senile cataracts, pediatric cataracts represent a significant cause of treatable childhood blindness, accounting for 7–20% of such cases [1–3]. Unlike adults, where vision is corrected immediately after the surgery, children require timely and appropriate treatment during the critical vision development stages, involving surgery and long-term ophthalmological management, including amblyopia treatment, for normal vision development [4,5]. Occurring during crucial visual development stages in children, pediatric cataracts can lead to permanent vision impairment by causing amblyopia [6–8]. The prevalence of pediatric cataracts ranges from 2.2 to 13.6 per 10,000 children; however, early treatment can effectively prevent blindness [6,9,10].

For cataracts, vision improvement options include glasses, contact lenses, and eye drops to slow progression. However, surgery remains the definitive treatment as these methods cannot clear a clouded lens [4]. Pediatric cataract surgery presents additional challenges such as the need for general anesthesia, longer surgery times, caregiver involvement, a high rate of postoperative complications, and ongoing vision care after surgery. These factors contribute to an increased ophthalmological burden and significant long-term social costs [11–13].

There is a paucity of nationwide data addressing the burden of pediatric cataracts, and therefore, healthcare policies for pediatric cataracts remain underdeveloped. Previous studies on the costs of pediatric cataract surgery relied on hospital data, featuring relatively small sample sizes and focusing on cross-sectional rather than longitudinal analyses [11–13]. Furthermore, to our knowledge, no studies have reported the costs incurred following cataract surgery over a long-term follow-up period, nor the expenses associated with complications after the surgery [12–17]. Therefore, a nationwide population-based study focusing on pediatric cataracts and detailing the medical costs incurred following cataract surgery was required.

This study aimed to analyze the medical costs incurred by pediatric patients who underwent cataract surgery under 5 years of age, following cataract surgery, including those related to postoperative complications, and to identify the factors influencing these costs. The findings could help develop a more comprehensive treatment system for pediatric cataracts.

Methods

Results

After applying the eligibility criteria, we identified 1,297 pediatric patients aged 0–5 years who underwent their first cataract surgery within the study period. The mean age was 2.18 years, with the highest proportions in the 0 and 1-year-old groups (23.2% and 22.5%, respectively), and the majority were male (56.8%). Regarding socioeconomic status, the largest segment of patients (37.2%) was within the 11th to 15th income quartiles (level 3). Regarding surgery types, 60.9% underwent both extra- and intra-lens extraction. After the cataract surgery, 23 patients experienced retinal detachment, and 36 developed glaucoma requiring further surgery (Table 1).

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Table 1. Baseline characteristics of the study population.

https://doi.org/10.1371/journal.pone.0328781.t001

Table 2 presents the HRU findings and cataract-related medical costs in the ophthalmology department over an 8-year follow-up period for pediatric patients who underwent cataract surgery. On average, each patient had 30 outpatient visits, 2.7 inpatient admissions, and 3 emergency department visits after the surgery. The respective median costs per patient in these settings were $661 for outpatient visits, $1,346 for inpatient admissions, and $122 for emergency department visits. Additionally, patients who developed retinal detachment following cataract surgery incurred a median 8-year cost of $4,347. Those with glaucoma incurred a median cost of $6,754, predominantly in the inpatient setting (S2 Table).

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Table 2. Healthcare resource utilization and medical costs* over 8 years after cataract surgery in pediatric cataract patients.

https://doi.org/10.1371/journal.pone.0328781.t002

Fig 1 illustrates the trends in annual HRU and medical costs per patient over 8-year follow-up after pediatric cataract surgery. Medical costs dropped sharply from $658 in Year 1 to $402 in Year 2, followed by a gradual decline over time. The average medical costs were $1,337 in the short term (Years 1–3), $522 in the medium term (Years 4–6), and $273 in the long term (Years 7–8). Similarly, the average number of annual HRU visits decreased from approximately 10 visits in Year to 5 visits by Year 8. Overall, both medical costs and HRU showed a consistent decrease over time.

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Fig 1. Trends in annual medical costs and healthcare resource utilization (HRU) and per patient over an 8-year follow-up period after pediatric cataract surgery.

The bar chart represents average annual frequencies of outpatient, inpatient, and emergency department (ED) visits, while the dashed line shows average annual medical costs per patient (in USD) among 1,297 patients.

https://doi.org/10.1371/journal.pone.0328781.g001

The results of the GLM analysis identifying factors influencing medical costs over 8 years following cataract surgery are presented in Table 3. The analysis revealed that older age at surgery correlated with higher medical costs. Patients with higher income levels incurred 0.4–0.5 times more expenses compared to those at the lowest income level. Notably, patients who experienced retinal detachment and glaucoma after cataract surgery incurred significantly higher costs (3.4 and 3.7 times more, respectively), than those without complications. Additionally, an increased number of cataract surgeries led to 1.7 times higher costs over 8 years. Factors such as sex, residence, medical institution type, and surgery type did not significantly impact the costs.

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Table 3. Generalized linear model analysis of factors affecting 8-year medical costs following cataract surgery (n = 1,297).

https://doi.org/10.1371/journal.pone.0328781.t003

Among patients who developed complications after cataract surgery, retinal detachment (n = 21) was observed 1.5 times, on average, over 6.7 years, with the first incidence typically around 5.5 years after surgery, leading to a median additional medical cost of $4,616 per patient. Similarly, glaucoma (n = 40) occurred approximately twice on average, with the first episode occurring approximately 5.2 years after surgery, resulting in a median additional cost of $3,617 per patient (Table 4).

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Table 4. Complication frequency, duration, and medical costs over 6.7 years among patients with complications after cataract surgery.

https://doi.org/10.1371/journal.pone.0328781.t004

Discussion

We examined the ophthalmic complications and economic burden following cataract surgery among pediatric patients, and factors influencing their medical costs in South Korea. The results demonstrated that pediatric cataract surgery had a significant impact on long-term economic burden and HRU. The age at surgery, income level, occurrence of complications, and number of cataract surgeries were factors associated with increased economic burden. The association between older age at surgery and higher medical costs may reflect increased clinical complexity and a greater need for follow-up care in older pediatric patients. Similarly, higher income levels were also associated with increased costs, which may be explained by greater healthcare access, use of additional services, and potentially higher expectations for follow-up care among higher-income families. Furthermore, by analyzing the additional medical expenses associated with complications following cataract surgery, we found that patients who experienced complications had additional burdens besides cataracts.

Previous studies on the cost of pediatric cataracts have predominantly utilized hospital data. Evans et al. reported annual direct costs related to pediatric cataract surgery in Zambia and Malawi (n = 232), ranging from $202 to $277 per person [12]. Similarly, Wang et al. estimated the total medical burden for patients under 10 years of age in China (n = 181) at $3,850, covering the pre-surgery, surgery, and post-surgery periods [11]. However, neither study adopted a specific follow-up period, preventing a precise assessment of postoperative cataract-related medical costs. Additionally, the cost data reported by Wang et al. were derived from medical receipts collected via questionnaires, possibly resulting in incomplete data and unreliable results. Both studies have limitations in representativeness owing to data confinement to specific regional hospitals, and institutional disparities between medical facilities further challenge the generalization of their findings [11,12].

In contrast, the Infant Aphakia Treatment Study, a clinical trial conducted in the United States, evaluated the 5-year treatment costs for infants with cataracts (n = 144) based on different vision correction methods. This study included the cost of consumables such as contact lenses and glasses, which are non-reimbursable in Korea, leading to a higher cost estimate than ours. Excluding these consumables, the 5-year cost ranged from $6,766 to $7,509 [22].

In South Korea, most studies on pediatric patients with cataracts have been limited to case reports that share clinical outcomes from single hospitals or compare surgical techniques [7,23–25]. Although these studies provide valuable clinical insights, they do not extensively address the economic aspects of pediatric cataract treatment. Ryu et al. estimated the total annual cost of cataract surgery at approximately 400 billion KRW, using data from the NHIS. However, their study primarily focused on senile cataracts of the elderly population with an average age of 69 years, and it did not provide specific insights into the pediatric population. It lacked details such as the median or average cost per pediatric patient and the pattern of medical expenses, which are crucial for understanding the financial burden of pediatric cataract surgery [16]. As virtually nothing is known about the economic burden of pediatric patients suffering cataracts, our results addressing HRU, medical costs, and its determinants are notable.

The clinical care pathway for pediatric cataract varies across countries, influenced by socioeconomic status, healthcare infrastructure, and resource availability. In high-income countries, timely surgical intervention and comprehensive postoperative care are generally more accessible, leading to better visual outcomes. In contrast, low- and middle-income countries often face delays in diagnosis and treatment due to limited healthcare access, financial constraints, and geographic barriers [26,27]. South Korea’s healthcare system, characterized by universal health coverage and high accessibility, enables early surgical intervention and consistent follow-up care. The incidence of pediatric cataract surgery in Korea is comparable to other high-income countries [16]. Therefore, while the absolute healthcare costs may differ due to variations in reimbursement systems (e.g., private insurance coverage for premium intraocular lenses or non-reimbursed services), the economic burden patterns identified in this study are likely generalizable to other high-income settings with similarly structured healthcare systems [28].

Several Asian countries with universal health insurance and high-quality ophthalmic infrastructure, such as Japan and Taiwan, provide a useful comparative context. For example, Taiwan has demonstrated that shifts in reimbursement policies (e.g., from fee-for-service to case payment) influence the adoption of advanced surgical techniques and long-term outcomes. Japan introduced the Diagnosis Procedure Combination (DPC) system, a per diem prospective payment system, to reduce hospital stays and control medical costs. The DPC system can reduce medical costs for cataract operations, which generally involve a longer length of stay [29,30]. These examples suggest that cost-control policies and reimbursement models significantly shape care pathways and economic burdens. Given the structural similarities of these healthcare systems to those of South Korea, our findings may inform broader policy discussions. Specifically, they support the need to promote equitable access to premium intraocular lenses (e.g., through modified reimbursement criteria), establish standardized postoperative monitoring protocols to minimize complication-related expenditures, and evaluate the feasibility of bundled or case-based payment models tailored to pediatric cataract care.

The strength of this study lies in its detailed and comprehensive analysis of medical costs and HRU in pediatric patients with cataracts using long-term, nationwide, population-based data. First, unlike most cataract research, which focused on adult populations, our study provides representative, real-world evidence of the economic burden associated with pediatric cataracts by utilizing data from a nationwide database. Given the rarity of pediatric cataracts, the comprehensive analysis of a population of 50 million ensures strong representativeness, minimizing the risk of missing data and reducing selection bias, which are significant strengths of this study. Second, the extended follow-up period of 8 years enabled us to meticulously track and analyze long-term trends in medical costs and resource utilization, offering invaluable insights into the prolonged economic impact of pediatric cataract surgery. Lastly, a notable methodological advancement in this study was the application of a GLM to address the skewed distribution typically observed in cost data. This approach allowed for a more precise analysis of the factors influencing medical costs. By correcting this skewness, our study could deliver a more accurate understanding of the economic burden associated with pediatric cataract surgery, thereby significantly enhancing the robustness of our findings.

Nonetheless, this study had several limitations, primarily owing to its retrospective nature and the data utilized. First, this study used data from 2004 to 2011 and thus does not reflect changes in surgical techniques or reimbursement policies. Since July 2012, cataract surgery has been included in the Diagnosis Related Group payment system, which may have reduced inpatient reimbursement levels and altered the cost structure. Advances in surgical techniques and a shift toward outpatient-based care may also have contributed to lower per-case costs. While the NHIS statistical yearbook suggests that per-person costs have remained relatively stable since 2012 (S3 Fig), future studies using updated data are needed to capture recent trends. Second, this study relied on claims data, which did not include non-reimbursement items such as therapeutic contact lenses, glasses used for visual rehabilitation, or biometry tests. This omission may result in a conservative estimation of medical costs and may not fully capture the true economic burden of pediatric cataract surgeries [19,31,32]. Similarly, the NHIS claims data do not include quality-of-life or functional vision outcomes, which limits assessing the broader clinical impact of pediatric cataract. Future studies incorporating clinical or patient-reported data are needed to address this gap. Furthermore, the retrospective nature of the data may also limit external validity, and findings should be interpreted with caution. Third, glaucoma was defined solely based on surgical codes, excluding patients treated with medication alone, which resulted in a small number of patients identified as having complications. This likely led to an underestimation of the total glaucoma population and its associated costs. Nevertheless, by focusing on surgically treated cases, our analysis reflects patients with more severe status and thus provides a conservative estimate of the complication-related cost burden. Fourth, formal goodness-of-fit diagnostics for the GLM (e.g., residual analysis, overdispersion checks) were not performed, which may limit the ability to fully validate model assumptions. However, the selected model structure is consistent with standard approaches for skewed cost data and was deemed appropriate based on prior evidence. Finally, we did not include costs for post-surgical visual rehabilitation tools, such as therapeutic lenses or glasses, as these are typically non-reimbursed and not captured in claims data. This might lead to an underestimation of the real-world economic burden on patients and caregivers, suggesting that actual cataract-related costs may be higher than reported.

Despite the mentioned limitations, we believe this study generated robust, long-term cost estimates for pediatric cataract patients, a population for which economic data is scarce. Unlike previous studies that focused on adult populations or small sample sizes, our research provides rare, population-level evidence in a vulnerable pediatric group by utilizing a large, nationally representative claims database.

The findings have practical implications for healthcare decision-makers. By identifying high-cost drivers such as postoperative complications and repeated surgeries, this study highlights the importance of early intervention and sustained long-term care. These insights can support more effective preventive strategies, resource prioritization, and healthcare planning in the field of pediatric ophthalmology.

In conclusion, we estimated long-term medical costs and key contributing factors—such as age, income level, and complications—among pediatric patients undergoing cataract surgery. These results provide meaningful economic evidence that can inform future policy and improve care strategies for children at risk of visual impairment.

Supporting information