Recurrence rate, time to recurrence, and associated factors after primary pterygium excision with conjunctival-limbal autograft: a prospective cohort study

Abstract

Background

Pterygium recurrence remains a major postoperative challenge in equatorial regions with high ultraviolet (UV) exposure. Although several clinical and inflammatory factors have been proposed as predictors, evidence remains inconsistent. This study aimed to estimate the recurrence rate after primary pterygium excision with conjunctival-limbal autograft and to explore potential demographic, clinical, surgical, and systemic inflammatory factors associated with recurrence in a Colombian cohort.

Methods

This prospective cohort study included patients ≥ 18 years undergoing primary pterygium excision with conjunctival-limbal autograft at a high-complexity ophthalmology center in Bogotá, Colombia, between January and August 2024. Patients were followed until recurrence or last ophthalmologic follow-up, up to 10 months postoperatively. Recurrence rate was calculated and exploratory bivariate analyses were performed. Kaplan–Meier survival curves were generated.

Results

Ninety-one patients completed follow-up. The mean age was 50.9 years ± 13.0 years, and 59.3% (n = 54) were female. The recurrence rate was 13.2%, with a median follow-up of 197 days. Younger age was significantly associated with recurrence in bivariate analysis (mean difference − 11.2 years, p = 0.005). No statistically significant detectable associations were observed between recurrence and sex, laterality, pterygium grade, surgeon experience, or systemic inflammatory indices (NLR, PLR, SII, LMR, CRP, and ESR) (all p > 0.05).

Conclusions

In this prospective cohort from a high-UV equatorial setting, the recurrence rate after primary pterygium excision was 13.2%. Younger age was associated with recurrence in exploratory analyses. The absence of statistically significant associations for systemic inflammatory markers and other variables should be interpreted cautiously, as the study may be underpowered to detect moderate effect sizes. These findings should be interpreted as hypothesis-generating and require confirmation in larger, adequately powered studies.

Background

Pterygium is an ocular surface disorder characterized by the wing-shaped fibrovascular proliferation of conjunctival tissue extending onto the corneal limbus [1, 2]. Recurrence, defined as the reappearance of fibrovascular tissue at the excision site remains the principal challenge in postoperative management [3, 4]. This is clinically relevant because recurrent pterygia are associated with greater morbidity, including refractive changes, visual axis involvement, and cosmetic concerns, all of which may constitute indications for primary surgery [1, 2]. Recurrent lesions also frequently require reoperation, exposing patients additional risks such as hemorrhage, infection, strabismus, corneal scarring, ulceration, and even corneal melting [5].

The global prevalence of pterygium is estimated at approximately 10%, with substantial geographic variation ranging from 2.8% to 33%, as reported in rural and urban Australia and rural China, respectively [6]. The “pterygium belt”, extending 37 degrees north and south of the equator, encompasses regions with the highest prevalence [1]. In Colombia, located within this belt, nationwide prevalence data are lacking, but clinic-based studies report rates between 7% and 12% [7, 8]. More than 90% of recurrences occur within the first three to six months after surgery [9, 10]. In 1994 a study estimated a 12-month recurrence rate of nearly 97%, but advances in surgical techniques have substantially reduced this risk, with recent publications reporting recurrence rates between < 1% and 17% as of 2022 [11–16]. In Colombia, recurrence has been reported between 2.5% and 6.2% [17, 18].

Ultraviolet (UV) radiation is the most significant risk factor for recurrent pterygium [1, 9]. Additional determinants described in the literature include surgical technique, characteristics of the primary pterygium, intrinsic patient factors, and local or systemic inflammation, although the underlying pathophysiology remains incompletely understood [1, 19]. Regarding surgical technique, recurrence has been associated with incomplete excision of pterygium tissue or Tenon’s capsule, in addition to the surgeon’s learning curve [1, 2, 20]. Conjunctival autograft and the P.E.R.F.E.C.T. technique (extensive tenonectomy with pterygium excision followed by a large conjunctival autograft) have demonstrated the lowest recurrence rates [4, 14, 16, 21, 22]. Among primary pterygium characteristics, higher pterygium’s grade, greater vascularization, and evidence of active perioperative growth, particularly with canalicular distortion, have been associated with increased recurrence risk [16, 23, 24]. Recurrent pterygia also show elevated local inflammatory and pro-angiogenic markers [1, 19].

Systemic inflammation has recently emerged as a potential contributor to pterygium recurrence [13, 25]. Several systemic inflammatory indices have been applied in ophthalmic research [25]. Traditional markers include C-reactive protein and erythrocyte sedimentation rate [26]. More recently, inflammation-related indices, including the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), and the systemic inflammatory index (SII) (calculated as neutrophil and platelet count divided by total lymphocytes), have gained interest as markers of systemic inflammatory imbalance [27–30]. In ophthalmic research, mean platelet volume, NLR, and PLR have been associated with primary pterygium, and NLR has been linked to pterygium recurrence in a Chinese population [13, 25, 31].

Recurrence rates in the Latin-American region remain poorly characterized and the pathophysiology and risk factors for recurrence are not fully understood, limiting the development of strategies for early identification of high-risk patients and initial management [19]. To contribute to this knowledge gap, this study aimed to estimate the recurrence rate of pterygium and to explore clinical and systemic inflammatory factors associated with recurrence in a cohort of patients treated at a high-complexity ophthalmology center in Bogotá, Colombia.

Methods

Study design and setting

This prospective cohort study was conducted at a high-complexity ophthalmology center in Bogota, Colombia, between January and August 2024. Written informed consent was obtained from all participants after surgery and prior to study inclusion.

Study population and follow-up

Adult patients (≥ 18 years) undergoing primary pterygium excision with conjunctival-limbal autograft at the institution during the study period were consecutively recruited. The surgical technique is described below. Patients were excluded if they developed severe postoperative inflammation precluding reliable clinical assessment of recurrence or had clinical suspicion of ocular surface squamous neoplasia.

A total of 156 patients met eligibility criteria. Routine postoperative evaluations were performed on the first postoperative day and one week after surgery for suture removal. To be included in the recurrence analysis, patients were required to have follow-up beyond the first postoperative week. Of the 156 eligible patients, 91 patients completed follow-up beyond the early postoperative period and constituted the final analytic cohort. Patients were followed from the date of surgery until documented recurrence or their last ophthalmologic visit, with a maximum follow-up duration of 10 months.

Surgical technique

Topical anesthesia or local infiltration of 2% lidocaine into the pterygium body was administered using a 30-gauge needle. The pterygium was excised from the pterygium base toward the limbus using forceps and Westcott scissors. Subconjunctival Tenon’s tissue was removed, and diathermy was applied as needed to achieve hemostasis. The corneal surface was smoothed using a No. 10 blade. Subsequently, a superior bulbar conjunctival graft of matching size was dissected, positioned over the bare sclera, and secured with a continuous 10 − 0 nylon suture. A compressive dressing was applied and left in place overnight. Postoperative management included preservative-free lubricants every two hours and tobramycin-dexamethasone eye drops. Antibiotic, anti-inflammatory drops were prescribed six times daily for the first two weeks. Additional fluorometholone was added and tapered if inflammation was observed during the first postoperative week.

Variables

The primary outcome was pterygium recurrence, defined as the presence of fibrovascular tissue in the surgical site, with or without corneal invasion [2, 3], confirmed by slit-lamp examination performed by an ophthalmologist at any time during follow-up. Time-to-recurrence was calculated from the date of surgery to the date of clinical diagnosis of recurrence. Patients without recurrence were censored at their last ophthalmologic visit.

Sociodemographic variables included age (years) and sex (female or male). Clinical variables included pterygium grade (I-III; where grade I was defined as extension between the limbus and a point midway to the pupil, and grade III as extension crossing the pupil margin [2]), anatomical location (nasal or temporal), operated eye (right or left), and the history and type of autoimmune disease (thyroid disease, connective tissue disease, other autoimmune conditions, or none).

The surgical variable assessed was surgeon experience, defined a priori based on cumulative surgical volume. Surgeons who had performed fewer than 100 pterygium excisions were classified as less experienced and performed the surgery under direct supervision, whereas surgeons with 100 or more procedures were classified as experienced and performed the surgery independently.

Systemic inflammatory indices were derived from complete blood count parameters and included: neutrophil-to-lymphocyte ratio (NLR) (neutrophils/lymphocytes), the systemic inflammatory index (SII) (neutrophils × platelets / lymphocytes), the platelet-to-lymphocyte ratio (PLR) (platelets/lymphocytes), and the lymphocyte-to-monocyte ratio (LMR) (lymphocytes/monocytes). Additionally, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were recorded. Laboratory measurements were obtained within two months prior to the last follow-up visit. These values were analyzed as continuous variables.

Baseline clinical and sociodemographic data were collected at enrolment, and laboratory tests were obtained within two months prior to the last follow-up visit.

Statistical analysis

Quantitative variables were summarized using measures of central tendency and dispersion, while categorical variables were reported as absolute and relative frequencies. The normality of quantitative variables was assessed using the Shapiro–Wilk test. Exploratory comparisons between patients with and without pterygium recurrence were performed using Student’s t-test for continuous variables and the chi-square or Fisher’s exact test for categorical variables, as appropriate.

The recurrence rate was calculated as the proportion of patients who developed recurrence during the follow-up. Incidence density was estimated by dividing the number of recurrence events by the total person-time at risk. Recurrence-free survival was estimated using Kaplan–Meier methods. Survival time was calculated from the date of surgery to recurrence or last follow-up (censoring). All statistical tests were two-sided, and a p-value < 0.05 was considered statistically significant. Analyses were performed using Stata version 16.0 (StataCorp, College Station, TX, USA).

Results

A total of 156 patients met eligibility criteria during the study period. Of these, 91 patients completed follow-up beyond the early postoperative period and were included in the recurrence analysis (Fig. 1). The median follow-up time was 197 days (interquartile range [Q1-Q3]: 188–223 days). Pterygium recurrence after surgical excision was observed in 13.2% of patients (n = 12). The overall incidence density was 6.28 per 10,000 person-days.

Fig. 1.

Participant flow chart

The mean age of participants was 50.9 ± 13.0 years, and 59.3% (n = 54) were female. Patients who developed recurrence were younger than those without recurrence (41.2 ± 9.2 vs. 52.4 ± 12.9 years; mean difference − 11.2 years; p = 0.005). Pterygium laterality was evenly distributed between the right (51.6%, n = 47) and left eyes (48.4%, n = 44), and most lesions were nasal (96.5%, n = 87). Grade II pterygium was the most frequent (59.3%, n = 54), followed by grade III (36.3%, n = 33). Most patients had no history of autoimmune disease (96.7%, n = 88). No statistically significant differences were observed between patients with and without recurrence regarding sex, laterality, pterygium location, pterygium grade, or history of autoimmune disease (Table 1).

Table 1.

Demographic and clinical characteristics of patients with and without pterygium recurrence

Variable	All (n = 91)	Pterygium recurrence		p value
		Yes (n = 12)	No (n = 79)
Age, mean (SD)	50.9 (13.0)	41.2 (9.2)	52.4 (12.9)	0.005
Sex, n (%)				0.755
Female	54 (59.3)	8 (66.7)	46 (58.2)
Male	37 (40.7)	4 (33.3)	33 (41.8)
Laterality of pterygium, n (%)				0.902
Right	47 (51.6)	6 (50.0)	41 (51.9)
Left	44 (48.4)	6 (50.0)	38 (48.1)
Location of pterygium, n (%)				0.438
Nasal	87 (95.60)	11 (91.7)	76 (96.2)
Temporal	4 (4.4)	1 (8.3)	3 (3.8)
Grade of pterygium, n (%)				0.380
I	4 (4.4)	1 (8.3)	3 (3.8)
II	54 (59.3)	8 (66.7)	46 (58.2)
III	33 (36.3)	3 (25.0)	30 (38.0)
History of autoimmune disease, n (%)				1.000
Thyroid disease	1 (1.1)	0 (0.0)	1 (1.3)
Connective tissue disease	2 (2.2)	0 (0.0)	2 (2.5)
None	88 (96.7)	12 (100.0)	76 (96.2)

*SD: Standard deviation

Recurrence rate was also evaluated according to surgeon experience. Of the 91 procedures, 22 were performed by experienced surgeons and 69 by less experienced surgeons. The recurrence rate was 18.2% (4/22) among experienced surgeons and 11.6% (8/69) among less experienced surgeons, without statistically significant difference between groups (Fisher’s exact p > 0.474).

Postoperative complications were infrequent. Three patients (3.35%) presented with suture retention associated with mild inflammation at one month after surgery, and one patient (1.1%) developed corneal dellen.

No statistically significant differences were detected in the mean values of systemic inflammatory indices between patients with and without recurrence. The mean values for the overall cohort were as follows: ESR 10.6, CRP 2.4, NLR 2.0, SII 596.6, PLR 147.3, and LMR 4.8 (Table 2).

Table 2.

Systemic inflammatory parameters according to pterygium recurrence status

Variable, mean (SD)	All (n = 91)	Pterygium recurrence		Mean difference	p value
		Yes (n = 12)	No (n = 79)
Erythrocyte sedimentation rate (mm/hour)	10.6 (10.4)	9.2 (5.9)	10.8 (10.9)	1.6	0.612
C-reactive protein (mg/L)	2.4 (2.7)	2.4 (2.4)	2.4 (2.8)	0.0	0.975
Neutrophil-to-lymphocyte ratio	2.0 (1.9)	1.8 (0.7)	2.0 (2.0)	0.2	0.671
Systemic immune-inflammation index	596.6 (591.1)	553.4 (264.3)	603.2 (626.3)	48.8	0.787
Platelet-to-lymphocyte ratio	147.3 (80.4)	145.1 (37.1)	147.7 (85.2)	2.6	0.919
Lymphocyte-to-monocyte ratio	4.8 (1.7)	4.9 (1.9)	4.7 (1.7)	-0.2	0.721

Recurrence-free survival was estimated using the Kaplan–Meier method (Fig. 2). Because fewer than 50% of patients experienced recurrence during follow-up, the median recurrence-free survival was not reached.

Fig. 2.

Kaplan–Meier curve of recurrence-free survival

Discussion

This prospective cohort study estimated the recurrence rate of primary pterygium following conjunctival-limbal autograft surgery and explored potential demographic, clinical, surgical, and systemic inflammatory factors associated with recurrence in a Colombian population. The observed recurrence rate of 13.2% is consistent with previously reported rates ranging from 7.6% to 19.0% [12, 13, 16, 22], although it exceeds the lower rates described in Colombian cohorts (2.5–6.2%) [17, 18]. Differences across local and global studies may reflect variation in follow-up duration, surgical technique, patient characteristics, environmental exposure, underdiagnosis and methodological design.

The follow-up period extended to 10 months. Although structured long-term follow-up was intended, variability in postoperative attendance may have influenced the timing of documented recurrences. Most published studies report that the majority of recurrences occur within the first six to twelve months postoperatively [9–13, 21]. In the present cohort, recurrence detection occurred within this timeframe; however, given heterogeneous follow-up adherence, the observed temporal distribution should be interpreted cautiously, as detection timing may not perfectly reflect biological onset. This finding supports the need for structured and prolonged follow-up in comparable clinical settings.

Among the clinical factors explored, younger age was associated with recurrence in bivariate analysis. This observation is consistent with prior studies suggesting that younger individuals may exhibit enhanced fibrovascular proliferative activity, including accelerated re-epithelialization, angiogenesis, and collagen synthesis [19, 23, 32, 33]. Additionally, younger patients may have greater occupational or lifestyle ultraviolet exposure, which remains the most consistently reported environmental risk factor for both primary and recurrent pterygium [9]. However, given the limited number of recurrence events in this study, this finding should be considered exploratory and requires confirmation in larger, adequately powered cohorts.

No statistically detectable associations were detected between recurrence and sex, laterality, pterygium grade, autoimmune disease history, and surgeon experience, in agreement with other reports [13, 34]. With only twelve recurrence events, the study lacked sufficient statistical power to detect moderate associations or to perform reliable multivariable modeling according to established events-per-variable principles. Therefore, the absence of statistically significant findings should not be interpreted as evidence of absence of association.

Recurrence rates did not differ according to surgeon experience (18.2% vs. 11.6%). While this finding may suggest that standardized surgical technique is critical regardless of surgeon seniority, the study was not powered to definitively evaluate this comparison. Prior studies have indicated that surgical learning curve and meticulous Tenon’s capsule excision influence recurrence rates, reinforcing the importance of standardized surgical technique over surgeon experience alone [15, 20, 34]. However, larger samples would be necessary to clarify this relationship.

Similarly, systemic inflammatory indices (ESR, CRP, NLR, SII, PLR, and LMR) were not significantly associated with recurrence in this cohort. Previous studies have suggested that elevated NLR and SII may predict recurrence [13]; however, findings remain inconsistent across populations. In the present study, mean inflammatory marker values (ESR 10.6 mm/h, CRP 2.4 mg/L, NLR 2.0, SII 596.6, PLR 147.3, and LMR 4.8) were within reference ranges reported for healthy populations in Europe and Asia [29, 35–39], which may have reduced contrast between groups. Furthermore, inflammatory indices were not systematically collected at a standardized preoperative baseline time point. Because laboratory measurements were obtained within two months prior to the last follow-up visit, reverse causation bias cannot be excluded; inflammatory markers may have reflected postoperative or subclinical inflammatory activity rather than true preoperative systemic inflammatory status. It remains plausible that recurrence-related inflammatory mechanisms are predominantly localized to the ocular surface rather than systemic, as suggested by studies demonstrating elevated tear cytokines and local matrix metalloproteinases activity in recurrent disease [27, 40, 41]. Future adequately powered, multicenter studies are required to determine whether systemic inflammatory markers have predictive utility in selected subgroups.

Given the socioeconomic burden associated with recurrence, including the need for a second surgery, postoperative disability, and increased healthcare costs, identifying potential risk markers is particularly important in resource-limited settings such as Colombia. Decisions regarding more extensive surgical techniques, such as the P.E.R.F.E.C.T. technique, or the use of adjuvant therapies (e.g., 5-fluorouracil or mitomycin C), which have been shown to reduce recurrence rates in selected settings should remain individualized and guided by existing evidence [4, 9, 42, 43]. This is particularly important given the potential adverse effects associated with these interventions [9, 18]. All patients, especially younger individuals, should be advised to use UV-blocking sunglasses, as UV exposure remains the strongest environmental risk factor for both pterygium development and recurrence [9].

This study has several limitations. The small sample size and limited number of recurrence events reduced statistical power and precluded multivariable regression analysis. Non-significant findings must therefore be interpreted as statistically inconclusive rather than confirmatory. Loss to follow-up beyond the early postoperative period may have introduced selection bias if non-attending patients differed systematically in recurrence risk. Because baseline characteristics of patients lost to follow-up were not systematically compared with those included in the final analytic cohort, differential attrition cannot be excluded. Consequently, the reported recurrence rate may underestimate the true incidence. Additionally, operative time was not recorded and could not be evaluated as a potential surrogate marker of surgical thoroughness, particularly regarding removal of subconjunctival elastotic tissue. Ocular surface inflammatory conditions such as meibomian gland dysfunction and dry eye disease were also not systematically assessed, limiting the comprehensiveness of recurrence risk evaluation. Despite these limitations, this study provides prospective data from a high-UV equatorial setting within Latin America, a region where recurrence patterns remain insufficiently characterized. By explicitly framing the findings as exploratory, this cohort contributes hypothesis-generating evidence that may inform the design of future multicenter studies incorporating standardized baseline inflammatory assessment, comprehensive confounder measurement, extended follow-up, and adequate statistical power to clarify recurrence risk determinants.

Conclusions

This prospective cohort study estimated a pterygium recurrence rate of 13.2% following primary excision with conjunctival-limbal autograft in a Colombian population residing within a high-UV equatorial setting. Younger age was associated with recurrence in bivariate analyses, highlighting the potential importance of careful postoperative surveillance in younger patients pending confirmation in larger studies. No statistically detectable associations were observed for sex, pterygium grade, surgeon experience, or systemic inflammatory indices. These results are statistically inconclusive and do not exclude potentially clinically meaningful relationships. Inflammatory markers were not obtained at a standardized preoperative baseline point, further limiting causal interpretation. Although these results do not exclude a potential role of systemic inflammation, future adequately powered studies incorporating preoperative baseline inflammatory measurements are required to clarify the predictive value of these markers.

Abbreviations

P.E.R.F.E.C.T. technique

Pterygium Extended Removal Followed by Extended Conjunctival Transplant technique

NLR

Neutrophil-to-lymphocyte ratio (neutrophils/lymphocytes)

SII

Systemic inflammatory index (neutrophils × platelets / lymphocytes)

PLR

Platelet-to-lymphocyte ratio (platelets/lymphocytes)

LMR

Lymphocyte-to-monocyte ratio (lymphocytes/monocytes)

CRP

C-reactive protein

ESR

Erythrocyte sedimentation rate

UV

Ultraviolet

Author contributions

MPB collaborated with AMBD in developing the study concept, expanding her initial idea. Along with JVRL, developed the study design and protocol. Performed all clinical evaluations during follow-up visits and collected the data. Built the study database and co-wrote the manuscript with LMMR. Approved the final version. LMMR assisted MPB in coordinating and scheduling follow-up visits. Co-wrote the manuscript with MPB and approved the final version. JBC provided ongoing epidemiological support throughout the study, including assistance in addressing follow-up challenges and resolving issues related to required data. Performed all data analyses. Contributed to writing the manuscript and approved the final version. AMBD co-developed the research idea and contributed to the study conception and design. Provided ophthalmologic expertise throughout the project. Critically revised, proofread, and approved the final manuscript. JVRL contributed to the study design and protocol, particularly from the epidemiologic perspective. Proofread, edited, and approved the final version of the manuscript.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. No external financial support was provided for the conception, design, data collection, analysis, or preparation of the manuscript. All surgical procedures were part of routine clinical care and covered by the national healthcare system; no study-related costs were incurred.

Data availability

The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved by the Ethics Committee of Fundación Universitaria Sanitas under Minute No. CEIFUS 3825-23 (12/12/2023). The research was conducted in accordance with the ethical principles of the Declaration of Helsinki and applicable national regulations. All patients provided written informed consent to participate in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.