Clinical outcomes of pterygium surgery over a ten-year period: a review of recurrence and complication rates

Abstract

Purpose

This study described the clinical profile and post-operative outcomes of patients who underwent pterygium surgery at an ambulatory eye center in the Philippines over a ten-year period.

Methods

This retrospective study analyzed medical records of 462 eyes from 408 patients who underwent pterygium surgery by a single surgeon between February 2013 and August 2023. The study examined the clinical characteristics of patients with pterygium and evaluated the recurrence rates of three treatment methods: pterygium excision with conjunctival autograft (CAG), pterygium excision with dehydrated amniotic membrane graft (DAG), and primary excision with mitomycin C application. Descriptive statistics were used for analysis of patient demographics, clinical profile, and postoperative outcomes.

Results

The mean patient age was 48 years (range 17–81), with a slight male predominance (57%). Nasal pterygium was the most common type (72%), followed by bipolar (8%) and temporal (3%) pterygium. Most cases were primary (81%), with T2G1 being the most common grading. Conjunctival autograft was the predominant surgical technique (94%), followed by dehydrated amniotic membrane graft (5%) and primary excision with mitomycin C application (1%). The overall recurrence rate was 1%, with conjunctival autograft showing the lowest rate, compared to dehydrated amniotic membrane graft and primary excision with mitomycin C. The complication rate was 4.5%, primarily minor findings such as conjunctival granuloma, wound dehiscence, and residual pterygium.

Conclusion

Most pterygium cases presented as primary and in the nasal area with T2G1 grading. This study supports conjunctival autograft as the preferred surgical technique for pterygium because of the low recurrence and complication rates.

Introduction

Pterygium is a triangular, vascularized growth of conjunctival tissue encroaching onto the cornea [1, 2]. It is prevalent within 36 degrees latitude of the equator, which includes tropical countries like the Philippines. Ultraviolet B radiation is the primary etiological factor, along with genetic and environmental contributors [3–5]. A meta-analysis by Liu et al. found that pterygium affects 10.2% of the global population⁶.

Current management of pterygium primarily involves surgical excision, with recurrence prevention being the main challenge. Recurrence is generally defined as corneal regrowth of fibrovascular tissue [5]. Surgical approaches range from simple bare sclera excision, associated with high recurrence rates (24–89%), to more complex procedures [2–7]. Conjunctival autografting (CAG) is widely recognized as the preferred procedure for pterygium surgery, established as the “gold standard” due to its efficacy and safety², with recurrence rates varying from 2–39%[9, 10, 11, 12, 13, 14, 15, 16]. Adjuvant therapies include mitomycin C (MMC), which effectively reduces recurrence but carries risks such as delayed wound healing [8, 12, 20, 24]. Amniotic membrane grafting has also been employed, though with varying recurrence rates, and previous research indicates that it is less effective than conjunctival autografts [17, 18, 20–24].

Pterygium recurrence rates are influenced by racial and geographical factors, with higher rates among certain populations and in low-latitude regions [25–26]. These findings underscore the importance of region-specific research and meticulous tracking of recurrence rates. Recurrence remains the primary concern following pterygium surgery, often presenting more severe complications than the initial occurrence. These potential consequences underscore the need for comprehensive long-term follow-up and studies. A gap exists in local research offering information on a series of pterygium surgeries performed by a singular surgeon over an extended period, presenting an opportunity to investigate the efficacy of various surgical techniques.

This study aims to address this research gap by examining the clinical characteristics of pterygium patients and evaluating the recurrence rates of three surgical procedures: pterygium excision with conjunctival autograft, pterygium excision with dehydrated amniotic membrane, and primary excision with mitomycin C application. To our knowledge, this is the first local, comprehensive study spanning 10 years of data analyzing clinical outcomes of pterygium surgery. Through rigorous examination of these aspects, we aim to contribute valuable insights to pterygium management and refine surgical approaches, ultimately leading to evidence-based improvements in patient care.

Materials and methods

Sample population

This retrospective cohort study encompassed all patients who underwent pterygium excision performed by a single corneal surgeon at an ambulatory eye center between February 2013 and August 2023. Exclusion criteria included cases with insufficient clinical data, surgical techniques not specified in the study protocol, and those who underwent combined procedures (e.g., combined pterygiectomy and cataract extraction).

Ethical consideration

The study protocol received approval from the institutional ethics review committee. Given the retrospective nature of the study, the committee granted a waiver of the requirement for informed consent. All patient information gathered during this study was kept anonymous and confidential. For anonymity, patients were assigned case numbers. The authors declare no financial interest in any products mentioned in this study, nor have they received any related funding.

Data collection

A standardized data collection form devised by the primary author was used. Patient demographics such as age and gender were collected, as well as the clinical profile, such as pterygium location, laterality, grading, and type (primary or recurrent). The surgical outcomes were classified and evaluated in terms of recurrence rate and surgical complications. These data were collected and input manually into Microsoft Excel (Microsoft Corporation, Redmond, WA, USA).

Grading of pterygium

The pterygium classification system employs two key criteria. The first, developed by Tan et al. [15]assesses relative translucency, categorizing pterygia as T1 (atrophic), T2 (intermediate), or T3 (fleshy) based on the visibility of underlying episcleral vessels. T1 pterygia have clearly visible episcleral blood vessels under the pterygium body, T2 exhibit characteristics between atrophic and fleshy, and T3 have completely obscured episcleral vessels. The second criterion, established by Sejal Maheshwari [34]evaluates the extent of corneal involvement. Grade 1 pterygia extend between the limbus and a point midway between the limbus and the pupillary margin. Grade 2 pterygia have their head present between the midway point and the pupillary margin. Grade 3 pterygia cross the pupillary margin (Fig. 1). For temporal pterygia, the temporal pupillary margin serves as a reference, while for nasal pterygia, the nasal pupillary margin is used. The grading of pterygium across different surgical techniques—Conjunctival Autograft (CAG), Dehydrated Amniotic Graft (DAG), and Primary Excision with Mitomycin-C—shows a varied distribution. Most cases were treated with CAG, particularly in lower grades such as T1G1 (15.7%), T2G1 (40.5%), and T2G2 (29.3%). In contrast, DAG was used much less frequently, with a notable presence in T1G1 (41.7%) and sparse representation in other grades. The Primary Excision with Mitomycin-C technique was rarely used, appearing only once, in the T2G1 category (100%). Statistically significant differences among techniques were observed primarily in the T1G1 category (p = 0.0332), suggesting some correlation between surgical technique and specific grades of pterygium. Overall, CAG appears to be the most widely applied and versatile method across the grading spectrum.

Fig. 1.

Grading of pterygium. A, T1 - atrophic. B, T2 - intermediate. C, T3 - fleshy. D, G1 - pterygia extend between the limbus and a point midway between the limbus and the pupillary margin. E, G2 - pterygia have their head present between the midway point and the pupillary margin. F, G3 - pterygia cross the pupillary margin

Description of the surgical techniques

All surgeries were performed by a single experienced surgeon. Subconjunctival lidocaine-epinephrine anesthesia was administered. The pterygium excision involved detaching the pterygium head and meticulously dissecting the body from the overlying conjunctiva. After completing the excision, the bare scleral area was measured.

Primary pterygium excision with mitomycin C

For primary pterygium excision with mitomycin C application, 0.02% mitomycin C-soaked sponges were applied under the edges of the recipient conjunctiva for 2 min. This was followed by copious irrigation with 20 cc of balanced salt solution. The conjunctiva was then repositioned and sutured to cover the bare sclera.

Pterygium excision with conjunctival autograft (CAG)

In the conjunctival autograft group (Fig. 2), a thin, Tenon’s-free graft was carefully harvested from the superior bulbar conjunctiva. The graft was sized 1 mm larger than the donor site. It was then secured in place using interrupted 10 − 0 Polyglactin 910 (Vicryl) sutures, with corner sutures anchored to the underlying episclera.

Fig. 2.

Representative images of conjunctival autograft (CAG) outcomes. Figures A, B, Preoperative slit lamp photos from a case of recurrent pterygium with T2G3 grading on the nasal side. Figures C, D, Postoperative outcomes 14 months after CAG

Pterygium excision with dehydrated amniotic membrane graft (DAG)

For the dehydrated amniotic membrane group (Fig. 3), adjuvant intraoperative mitomycin C was given similar to the primary excision, and then the membrane (AmnioTek™ processed human amniotic membrane, ISP Surgical, LLC Technologies Inc.) (Fig. 4) was trimmed 1 mm larger than the bare scleral bed while still in its surgical packaging. Upon application, it was hydrated and its edges were carefully tucked under the recipient conjunctiva and sutured in place using interrupted 10 − 0 Polyglactin 910 (Vicryl) sutures, with corner sutures anchored to the underlying episclera. Care was taken to ensure that the membrane remained flat and properly positioned. Intraoperative subconjunctival triamcinolone 40 mg/ml 0.1 ml injection was done at the end of the surgery.

Fig. 3.

Representative images of dehydrated amnion graft (DAG) outcomes. Figures A, B, Preoperative slit lamp photos from two different patients. Figures C, D, Postoperative outcomes corresponding to Figures A and B, after DAG

Fig. 4.

Intraoperative image of the amniotic membrane (AmnioTek™ processed human amniotic membrane, ISP Surgical, LLC Technologies Inc.)

Post operation

Postoperatively, patients were prescribed steroid-antibiotic and lubricant eye drops to be administered four times daily for 4–6 weeks. They were also instructed to apply steroid-antibiotic ointment at bedtime for the first week after surgery. Follow-up appointments were scheduled at 1 week, 1 month, 2 months, 3 months, and every 6 months thereafter.

Statistical analysis

Descriptive statistics were employed for data analysis. For continuous variables, means and standard deviations were calculated, while frequencies and percentages were used for categorical data. This approach was applied to patient demographics, clinical profiles, and post-operative outcomes. Analysis of variance (ANOVA) was utilized for continuous data, and the chi-square test was used for categorical variables. Statistical significance was set at a P value of < 0.05.

Results

A retrospective analysis was conducted on 462 eyes from 408 patients who underwent pterygium excision between February 2013 and August 2023. Table 1 presents the baseline demographics and clinical characteristics of the patients. The mean age of patients undergoing conjunctival autograft was 47.2 ± 13.5 years, with an overall age range from 17 to 81 years. The majority of patients were male (56.8%), compared to female (43.2%).

Table 1.

Patient demographics and clinical profile per surgical technique

	Conjunctival Autograft (CAG)	Dehydrated amniotic membrane graft (DAG)	Primary excision with Mitomycin-C	p value
n (patients)	387	18	3
Age (years), mean ± SD	47.2 ± 13.5	59.8 ± 13.9	65.7 ± 4.2	0.0001
Age Range	17–81
Gender, n, %
Male	218 (56.8)	11 (61.1)	2 (66.7)	0.884
Female	166 (43.2)	7 (38.9)	1 (33.3)
n (eyes)	433	25	4
Location
Bipolar	28 (7.7)	5 (33.3)	1 (33.3)	0.0067
Nasal	319 (73.7)	10 (55.6)	2 (66.7)
Temporal	15 (4.1)	0 (0.0)	0 (0.0)
Type
Primary	347 (83.6)	24 (96.0)	4 (100)	0.1739
Recurrent	68 (16.4)	1 (4.0)	0 (0.0)

Surgical interventions

The predominant surgical technique utilized in this study was excision with conjunctival autograft, performed in 94% of the cases, followed by pterygium excision with dehydrated amnion graft in 5% of cases, and primary excision with Mitomycin-C (MMC) in 1%. In the interest of methodological transparency, it is noteworthy that the study included two cases where a combination of dehydrated amnion graft (DAG) and conjunctival autograft (CAG) was employed for patients presenting with bipolar pterygium. For analytical purposes, these cases were classified within the amnion graft cohort. The combined surgical approach was necessitated by insufficient superior conjunctival tissue availability to adequately cover both surgical sites. A particularly illustrative case involved a patient presenting with T3G3 pterygium on the temporal aspect and T2G2 on the nasal aspect. The surgical intervention comprised CAG on the temporal side and DAG on the nasal side. Post-operative follow-up at 6 months revealed no recurrence, demonstrating the potential efficacy of this combined approach in managing complex bipolar pterygium cases.

Postoperative outcomes and recurrence rate

The mean follow-up period was 14 months, with 57% and 31% of patients reaching minimum follow-up durations of 6 months and 1 year, respectively. As illustrated in Table 2, the overall recurrence rate was 1% (6 out of 462 eyes). Recurrence is noted when there is a fibrovascular tissue invading the cornea. Surgical techniques demonstrated varying efficacy in preventing recurrence: CAG exhibited the lowest rate (0.7%), followed by DAG (8%), while primary excision with mitomycin-C application showed the highest recurrence rate (25%).

Table 2.

Post-operative recurrence rate

	Number of Eyes (n = 462)	Percentage (%)
No recurrence	456	99%
With Recurrence	6	1%
Conjunctival Autograft	3 out of 433	0.7%
Dehydrated amniotic membrane graft	2 out of 25	8%
Primary excision with Mitomycin-C	1 out of 4	25%

In the conjunctival autograft cohort, pterygium recurrence was observed in three subjects (n = 3). The first case involved a 57-year-old male with occupational maritime exposure, presenting with a recurrent, bipolar, T2G2 pterygium. Recurrence was noted at 2 months post-operation. The second case, a 29-year-old male with similar occupational exposure, exhibited recurrence of a primary nasal pterygium at 6 months post-operation. The third case, a 26-year-old male engineer, experienced recurrence of a primary nasal pterygium at 1-month post-operation.

The amnion graft cohort demonstrated two instances of recurrence (n = 2). The first case involved a 69-year-old unemployed female with a primary, nasal T2G1 pterygium, with recurrence observed at 7 months post-operation. The second case, a 35-year-old female employed as a physical education instructor, presented with recurrence of a primary nasal T2G2 pterygium at one-month post-operation.

In the primary excision + MMC cohort, a single case of recurrence (n = 1) was documented. This involved a 6¹-year-old female with a primary nasal pterygium, with recurrence manifesting at 7 months post-operative.

Recurrence was observed in all three surgical groups, with varying frequencies. These recurrences manifested between 1 and 7-months post-operation in patients aged 26–69 years, encompassing both primary and recurrent pterygia cases. The affected individuals represented a heterogeneous occupational demographic, with a predominance of professions associated with elevated ultraviolet radiation exposure. Furthermore, the recurrent cases exhibited pterygium grades of T2G1 and T2G2.

Complications

The study revealed an overall postoperative complication rate of 4.5% as seen on Table 3. CAG showed a 4.6% complication rate, with wound dehiscence (1%) and conjunctival granuloma formation (0.7%) being the most common adverse events (Fig. 5). DAG had a higher complication rate of 8.33%, including one case each of conjunctival congestion and granuloma. Interestingly, and probably due to low numbers performed, primary excision with mitomycin-C application resulted in no documented complications.

Table 3.

Post-operative complications per surgical technique

	Conjunctival Autograft (CAG)	Dehydrated amniotic membrane graft (DAG)	Primary excision with Mitomycin-C	p value
Without	396 (95.4)	22 (91.7)	4 (100)	0.6347
With	19 (4.6)	2 (8.3)	0 (0.0)
Conjunctival congestion	1 (0.2)	1 (4.2)	0 (0.0)
Conjunctival Cyst	1 (0.2)	0 (0)	0 (0.0)
Conjunctival granuloma	3 (0.7)	1 (4.2)	0 (0.0)
Corneal Scar	2 (0.5)	0 (0)	0 (0.0)
Dellen	2 (0.5)	0 (0)	0 (0.0)
Graft dehiscence	2 (0.5)	0 (0)	0 (0.0)
Residual Pterygium cornea	2 (0.5)	0 (0)	0 (0.0)
Steroid-induced Ocular HPN	2 (0.5)	0 (0)	0 (0.0)
Wound gape	4 (1)	0 (0)	0 (0.0)

Fig. 5.

Complications of pterygium surgery. (A) Conjunctival granuloma. (B) Conjunctival Cyst. (C) Wound dehiscence

Discussion

This study is the first comprehensive investigation in the Philippines, spanning 10 years of data on a large number of pterygium surgery patients. The global prevalence of pterygium remains substantial, with a pronounced concentration in equatorial regions. Our study found a slightly higher prevalence of pterygium in males (57%) compared to females (43%), aligning with previous studies that have consistently reported a male preponderance [6, 17]. This gender disparity may be attributed to varying occupational exposure to environmental risk factors. Notably, our findings diverge from the first and only published epidemiologic study on pterygium in the Philippines, which reported a female preponderance, citing cosmetic concerns as the primary motivation for surgery among women [27].

The mean age of 48 years observed in this cohort is consistent with the typical age range for pterygium development [5]reinforcing our understanding of the condition’s age-related progression. Nasal pterygium predominated (72%), likely due to increased environmental exposure [17, 28]. This pattern, consistently reported across diverse populations, is believed to stem from the increased exposure of the nasal conjunctiva to environmental factors such as ultraviolet (UV) radiation and airborne particulates [17]. Another important observation from this study is the high proportion of cases (81%) presenting as primary pterygium. This underscores the importance of early intervention and comprehensive patient education to prevent recurrence. Early detection and management can significantly improve outcomes and reduce the need for repeated surgical interventions [30].

In contrast to the aforementioned local epidemiologic study, which identified T2G2 (Type 2, Grade 2) as the predominant pterygium type [32]our investigation revealed a preponderance of T2G1, with T2G2 as the second most prevalent. Pterygium grading in our study was conducted by a single, experienced cornea surgeon, reducing inter-grader variability. The observed discrepancy between studies may stem from the subjective nature of pterygium grading methods. This highlights the pressing need for standardized grading systems in pterygium assessment, which would facilitate more accurate comparisons across studies and improve clinical decision-making. Furthermore, our data suggest that the extent of corneal encroachment may not be the sole determinant for patients seeking surgical consultation. The translucency and thickness of the pterygium (T2 grading) can also serve as significant factors prompting patients to consult and ultimately undergo surgery, primarily due to its visibility and cosmetic impact, even in cases where corneal encroachment is minimal. This observation explains why most patients in our cohort who had surgical intervention presented with a T2 grading, regardless of the G grading. These findings highlight the multifactorial nature of pterygium-related surgical decision-making and emphasize the importance of considering both objective clinical measurements and subjective patient concerns in treatment planning.

Pterygium excision with conjunctival autograft has been our preferred surgical approach for over a decade, owing to its proven efficacy and favorable safety profile. This technique has demonstrated significantly lower recurrence rates compared to bare sclera excision (5% vs. 88% at 1 year) and superior cosmetic outcomes [29]. Furthermore, conjunctival autografts have shown better outcomes than amniotic membrane grafts in terms of recurrence rates (2.6% vs. 10.9%) and overall surgical success [13, 17–19].

Notably, the three recurrences observed in the conjunctival autograft group were confined to the initial two years of the study period (2013–2014), with no subsequent recurrences reported. This distribution of recurrence events suggests a potential correlation between surgical proficiency and outcomes. The absence of recurrences in the latter years of the study may be attributed to several factors, including enhanced surgical expertise, more precise pterygium dissection techniques, and overall improvement in surgical skills. This observation aligns with previous studies that have demonstrated a learning curve effect in pterygium surgery, where surgical outcomes tend to improve with increased operator experience [32].

While our study primarily focused on conjunctival autograft, it also yielded valuable insights into alternative techniques. Higher recurrence rates were observed with dehydrated amnion grafts (8%) and primary excision with mitomycin-C (25%). These findings align with previous literature suggesting that these approaches may be less effective than conjunctival autograft in preventing recurrence [17, 18]. However, it is important to note that the small sample sizes for these alternative techniques warrant cautious interpretation of these results.

A subset of patients in our study (n = 4) underwent primary excision with MMC. This approach was predominantly employed for individuals with a mean age of 67 years who had concomitant cataracts and were primarily concerned with expediting cataract surgery to improve their vision. These patients opted for quick pterygium removal to facilitate timely cataract surgery, thus declining conjunctival autograft harvesting. Their decision was influenced by the need to address the more visually significant cataract condition promptly.

Of particular relevance to our patient population, a local study by Agahan et al. [32] demonstrated that conjunctival autograft alone effectively reduced recurrence rates in both primary and recurrent pterygium cases, with no significant additional benefit from intraoperative low-dose MMC. These findings further corroborate the efficacy of conjunctival autograft as a standalone procedure for the majority of cases while emphasizing the importance of tailored surgical approaches for specific patient subgroups.

In 2015 to 2018, our institution adopted dehydrated amnion graft for pterygium surgery as the technique gained prominence. However, we discontinued this approach due to several factors. During the short period of amnion use, we observed two recurrences, which prompted a reevaluation of our surgical approach. A comprehensive meta-analysis by Clearfield et al. demonstrated that conjunctival autografting had a significantly lower recurrence rate (14%) compared to amniotic membrane grafting (35%) [35]. Furthermore, Bekibele et al. reported higher complication rates associated with amniotic membrane transplantation (20%) versus conjunctival autografting (5.7%). Corroborating these findings, a local prospective, interventional study conducted by Lo & Lim-Bon-Siong revealed that conjunctival autografts yielded superior cosmetic outcomes compared to amniotic membrane allografts [31]. These empirical findings, in conjunction with our clinical observations, led us to revert to our preferred method of conjunctival autografting. This technique has consistently demonstrated superior outcomes in terms of both efficacy and safety. Our experience underscores the importance of evidence-based decision-making in surgical practice and highlights the need for continuous evaluation of emerging techniques in ophthalmology. It is important to note, however, that amniotic membrane grafts retain a crucial role in specific clinical scenarios. These include advanced cases with bilateral pterygium where donor conjunctiva is insufficient to cover both sites, cases involving scarred conjunctiva, or patients for whom preservation of the superior conjunctiva is essential due to potential future glaucoma surgery [29].

Recurrences were observed across all surgical groups, with onset occurring between 1 and 7 months post-operatively. The age range of patients experiencing recurrence was 26–69 years, encompassing both primary and recurrent pterygium cases. Notably, a significant proportion of affected individuals had occupations associated with increased UV exposure, suggesting a potential risk factor for recurrence.

Analysis of pterygium grading revealed that the majority of recurrent cases were classified as T2G1 and T2G2. Interestingly, no Grade 3 patients experienced recurrence, indicating that the extent of corneal involvement was not associated with pterygium recurrence. This finding corroborates the results reported by Alsarhani et al. [17].

Furthermore, our study demonstrated that none of the 19 patients over 70 years of age experienced recurrence. This observation aligns with previous research indicating that younger age is a risk factor for pterygium recurrence following limbal conjunctival autograft procedures [13, 16–18]. The age-related difference in recurrence rates may be attributed to the decelerated wound-healing process associated with aging [33].

The recurrences observed in our present study were managed accordingly. Of the six patients who experienced recurrence, three (50%) underwent successful repeat pterygium excision with conjunctival autograft, resulting in complete resolution without further recurrence. The other three patients (50%) were lost to follow-up, preventing long-term outcome assessment. These results suggest the efficacy of our management protocol for recurrent cases. However, further research with larger sample sizes and longer follow-ups is needed to confirm these findings.

The safety profile of pterygium surgery, as demonstrated in this study, is favorable. The observed low complication rate of 4.5% and the absence of severe complications in 93% of patients underscore the procedure’s safety when performed by an experienced surgeon. Reported complications, including conjunctival granuloma, wound dehiscence, and steroid-induced ocular hypertension, are well-documented potential sequelae of pterygium surgery [31]. These complications were managed effectively, emphasizing the critical role of meticulous postoperative care and follow-up in ensuring optimal outcomes.

In conclusion, this 10-year study provides strong evidence supporting conjunctival autograft as the preferred surgical technique for pterygium management. The low recurrence and complication rates observed in this large cohort demonstrated that pterygium surgery with conjunctival autograft is a safe and effective procedure for primary and recurrent pterygia. For the limitations, the mean follow-up period of 14 months, although informative, highlights a potential area for improvement in future studies. Longer follow-up periods would be beneficial to assess long-term recurrence rates and complications, particularly given that some studies have reported late recurrences beyond the first post-operative year [32]. Newer techniques such as use of bioadhesive glues instead of sutures can be adopted and reported in future studies. Lastly, future research directions include prospective studies with longer follow-up periods, randomized controlled trials comparing different surgical approaches, investigations into factors influencing recurrence rates, and exploration of adjuvant therapies and patient-reported outcomes.

Abbreviations

CAG

Pterygium excision with conjunctival autograft (CAG)

DAG

Pterygium excision with dehydrated amniotic membrane graft (DAG)

MMC

Pterygium excision with Mitomycin C (MMC)

T1

Atrophic Pterygia

T2

Intermediate Pterygia

T3

Fleshy Pterygia

Author contributions

Design and conduct of the study (SIN, RTA); collection (SIN, ASN), management (SIN, RTA), analysis (SIN, RTA, ASN, EMC), interpretation of the data (SIN, RTA, ASN, EMC); manuscript preparation (SIN, RTA, ASN, EMC), manuscript review (SIN, ASN, RTA, EMC), manuscript approval (SIN, EMC).

Funding

The authors declare that no funding was received for conducting this work.

Data availability

The datasets generated and/or analyzed during the current study are not publicly available due to compliance with the National Data Privacy Law. However, they are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

In compliance with institutional guidelines for research involving human subjects, the St. Frances Cabrini Medical Center-Asian Eye Institute (SCMC-AEI) Ethics Review Committee has officially approved the study protocol and waived the need to obtain participants’ informed consent. The decision was made on the basis of the study’s retrospective design, low participant risk, and use of anonymized data. The decision was made after a careful evaluation of the research protocol and ethical issues, with a strong emphasis on protecting participant rights and welfare. All procedures were carried out in complete conformity to ethical norms and guidelines.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Consultant / advisory positions

RTA: Staar Surgical, Acevision, Acufocus, Bausch and Lomb, Johnson & Johnson, Physiol BVI

SIN, ASN, EMC: none.