Intra-lesional 5 fluorouracil for the management of recurrent pterygium

Modified Limbal-Conjunctival Autograft Surgical Technique: Long-Term Results of Recurrence and Complications

PURPOSE

The aim of this study was to report the recurrence and complication rates of a modified limbal-conjunctival autograft surgical technique for pterygium excision.

METHODS

This was a retrospective, single-surgeon, single-operating environment, consecutive case series of 176 eyes in 163 patients with a biopsy-proven diagnosis of pterygium. All patients underwent excision using a 23-gauge needle to "behead" the pterygium head, followed by a limbal-conjunctival autograft including ∼50% of the palisades of Vogt. Outcomes measured included recurrence, defined as any conjunctival fibrovascular growth, and complication rates. Correlations between preoperative patient characteristics, pterygium morphology, and intraoperative factors (width of corneal extension, conjunctival defect, and graft) with postoperative recurrence were examined using logistic regression models.

RESULTS

The median age was 59.5 years and 122 eyes (69.3%) had primary pterygium (type I: 17%, II: 37.5%, and III: 45.5%). Kaplan-Meier analysis demonstrated the median pterygium-free follow-up period to be 723 days (range 46-7230 days). Recurrence was observed in 3 eyes of 2 patients (1.7%). No postoperative graft-related complications were observed. Postoperative symptomatology was transient. Age demonstrated a negative correlation with recurrence (odds ratio 0.888, 95% CI, 0.789-0.998, P = 0.046). However, no other correlations with preoperative or intraoperative factors, including whether pterygium was primary or recurrent, were identified (all P > 0.05).

CONCLUSIONS

This modified limbal-conjunctival autograft technique represents an effective alternative that offers a very low recurrence rate and avoids extensive dissection or antimetabolites, with minimal complications and transient postoperative symptomatology, over a long-term follow-up period. This technique is relatively simple and successful for both primary and recurrent pterygia. Future comparative studies with other surgical techniques may determine which are superior.

5-Fluorouracil in primary, impending recurrent and recurrent pterygium: Systematic review of the efficacy and safety of a surgical adjuvant and intralesional antimetabolite

Pterygium is an ultraviolet-related disease characterized by an aberrant, wing-shaped and active wound-healing process. There is nothing quite as disheartening for the surgeon or patient as the recurrence of pterygium, and various adjuvants have been studied to ameliorate this. This systematic review provides a comprehensive summary of the efficacy and safety of 5-Fluorouracil (5-FU) as an antimetabolite agent for pterygium management. An appraisal of electronic searches of six databases identified 34 clinical studies reporting recurrence outcomes of 5-FU use in primary, impending recurrent and recurrent pterygia. In vitro and in vivo studies of 5-FU showed dose- and duration-dependent cytostatic and cytotoxic effects in human cells. 5-FU is relatively inexpensive, available, and easy to administer, making it attractive for resource-limited scenarios. However, the published evidence demonstrates a recurrence rate of 11.4-60% with the bare scleral technique, 3.5-35.8% with conjunctival rotational flaps, 3.7-9.6% with conjunctival autografts for intraoperative topical 5-FU, and 14-35.8% for preoperative and intraoperative injections. This suboptimal efficacy brings the role of 5-FU as an adjuvant for pterygium surgery into question and the authors do not recommend its use. In contrast, postoperative intralesional injections of 5-FU to arrest progression in impending recurrent pterygium and true recurrent pterygia were more promising, with success rates of 87.2-100% and 75-100%, respectively. Furthermore, 5-FU as a treatment modality, without surgery, effectively arrested progression in 81.3-96% of primary and recurrent pterygia. Other treatments such as topical and intralesional corticosteroids, cyclosporine and anti-VEGF agents are discussed. Complications of 5-FU increase with higher doses and range from transient and reversible to severe and sight-threatening. For pterygium, 5-FU has a predilection for causing scleral thinning, corneal toxicity, and graft-related complications. Additional study with extended follow-up is needed to elucidate the optimal dose, frequency, duration, and long-term safety of 5-FU injections. If 5-FU is used in the management of pterygium, it should be with caution, in selected patients and with vigilant long-term monitoring.

Rapid 3D bioprinting of a multicellular model recapitulating pterygium microenvironment

Pterygium is an ocular surface disorder with high prevalence that can lead to vision impairment. As a pathological outgrowth of conjunctiva, pterygium involves neovascularization and chronic inflammation. Here, we developed a 3D multicellular in vitro pterygium model using a digital light processing (DLP)-based 3D bioprinting platform with human conjunctival stem cells (hCjSCs). A novel feeder-free culture system was adopted and efficiently expanded the primary hCjSCs with homogeneity, stemness and differentiation potency. The DLP-based 3D bioprinting method was able to fabricate hydrogel scaffolds that support the viability and biological integrity of the encapsulated hCjSCs. The bioprinted 3D pterygium model consisted of hCjSCs, immune cells, and vascular cells to recapitulate the disease microenvironment. Transcriptomic analysis using RNA sequencing (RNA-seq) identified a distinct profile correlated to inflammation response, angiogenesis, and epithelial mesenchymal transition in the bioprinted 3D pterygium model. In addition, the pterygium signatures and disease relevance of the bioprinted model were validated with the public RNA-seq data from patient-derived pterygium tissues. By integrating the stem cell technology with 3D bioprinting, this is the first reported 3D in vitro disease model for pterygium that can be utilized for future studies towards personalized medicine and drug screening.

Efficacy of 5-Fluorouracil in the Treatment of Pterygium

Objective To determine the efficacy of 5-Fluorouracil (FU) in the treatment of pterygium. Methodology After meeting the inclusion criteria 101 patients were enrolled in this study. Informed consent and demographic information was taken from all the patients. Patients underwent ophthalmic clinical examination that included slit lamp examination to grade pterygium. Before starting 5-FU injections, all topical medication was stopped. After four weeks the effects of 5-FU and its efficacy was noted. The patients were reviewed again after six months to note any recurrence. All the collected data was entered and analyzed on Statistical Package for Social Sciences (SPSS) version 20 (IBM Corp., Armonk, NY). Results In our study the mean age of the patients was 37.74 ± 10.15 years, male to female ratio of the patients was 1.06:1. The primary type of pterygium was noted in 54 (53.5%) and recurrent was noted in 47 (46.5%) patients. The efficacy achieved in 88 (87.13%) patients, four had recurrence of pterygium and of 101 patients 26 underwent surgical excision. Conclusion The use of 5-FU is safe and effective for the treatment of pterygium and it can be implemented as a primary treatment especially in the hot temperate zone where it is very common and aggressive with high recurrence rate. 5-FU not only halts its progression but also reduces the size and vascularity thus decreasing the need for surgery and steroid use and preventing recurrence.

Recurrent pterygium: A review

Purpose:

To summarize the recent evidence regarding different aspects of pterygium recurrence.

Methods:

Human-based studies from PubMed, Scopus, and Google Scholar were identified using the following keywords: conjunctival disease, pterygium, recurrent pterygium, pterygium recurrence, pterygium management/surgery, conjunctival autograft (CAU), amniotic membrane graft/transplant, and adjuvant therapy (January 2009 to February 2021). We reviewed risk factors associated with the recurrence of pterygium, timing of recurrence, medical treatments to prevent from recurrence, and nonsurgical and surgical alternatives for management of recurrence.

Results:

Dry eye disease, black race, and young age are considered definite risk factors for recurrence. However, fleshy appearance of the pterygium and preoperative size remain controversial. Surgical techniques such as excessive suturing, insufficient conjunctival graft size, thick conjunctival graft with remained Tenon tissue, and postoperative graft retraction are considered possible risk factors for recurrence. Using fibrin glue instead of sutures can further reduce recurrence rates. Although recurrence could occur even after many years, most recurrences happen in the first 3–6 months after surgery. Multiple kinds of adjuvant medications are used before, during, or after the operation including mitomycin C (MMC), 5-fluorouracil (5-FU), corticosteroids, and anti-vascular endothelial growth factors (anti-VEGFs). Multiple weekly subconjunctival 5-FU injections are shown to be safe and effective in halting the progression of recurrent pterygium. Although topical bevacizumab is found to inhibit the growth of impending recurrent pterygium, the effect is mostly temporary. CAU is superior to amniotic membrane transplantation in the treatment for recurrent pterygia.

Conclusions:

There is yet to be a panacea in treating recurrent pterygium. Currently, there is not a globally accepted recommendation for treating recurrent pterygium with anti-VEGFs or 5-FU as a nonsurgical treatment. We strongly recommend using MMC as an adjunct to surgery in recurrent cases, with consideration of its specific complications. CAU is the most effective surgical treatment for recurrent pterygium, and other new surgical therapies need further investigation.

Postoperative treatment compliance rate and complications with two different protocols after pterygium excision and conjunctival autografting

AIM

To evaluate compliance rate to pterygium postoperative treatment with two different protocols.

METHODS

Review of clinical data of patients submitted to pterygium excision and conjunctival autografting in a single centre (and a single surgeon) in Barcelona between March 2014 and December 2017. Initial postoperative protocol (protocol 1) consisted of 4 months of topical steroids in a tapering fashion. Protocol 2 consisted of topical steroids tapered over 5 weeks. Compliance rate, complications and clinical outcomes were evaluated, and statistical comparisons were made.

RESULTS

120 surgeries were performed in 99 patients. Protocol 1 was applied in 63 cases and the next 57 followed protocol 2. Compliance with protocol 1 (57.6%) was lower than with protocol 2 (84.9%) (p = 0.002). Intraoperative complications (graft tear, corneal thinning, corneal perforation and bleeding) were found in 10 cases of protocol 1 and three cases of protocol 2, p = 0.08. Postoperative complications (graft dislocation, graft haematoma, ocular hypertension and recurrence) were found in 31 cases of protocol 1 (46.2%) and eight cases of protocol 2 (14%), p = 0.001. Six weeks after surgery, ocular hypertension was detected in eight cases corresponding to protocol 1 (13.6%) and two cases of protocol 2 (3.8%), p = 0.099. Recurrence rate during first year was higher in protocol 1 (26.3%) compared to protocol 2 (7.6%), p = 0.011. No cases of visual acuity worsening or infection were registered.

CONCLUSION

Protocol 2 has shown to have higher compliance rate than protocol 1 and less postoperative complications, proving to be a safe and effective postoperative treatment after pterygium surgery.

Management of primary pterygium with intra-lesional injection of 5 flurouracil and bevacizumab (Avastin)

BACKGROUND

To assess the efficacy of combined 5FU and Avastin injections in the treatment of primary pterygium METHODS: Sixteen eyes with primary pterygium received intralesional 5 fluorouracil and Avastin (2.5-5 mg) injections every 2 weeks for a maximum of five injections. Fourteen eyes of 14 patients received five injections, one eye received three injections and one eye received two injections. All eyes were followed at monthly intervals for 3 months after last injection. Tissue was obtained by surgical excision of primary pterygium from four eyes who received injections and three eyes with primary pterygium who did not receive injections (control) and subjected to immunohistological examination for beta fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), von-Willebrand factor (vWF), lymphatic vessel endothelial hyaluronan receptor (LYVE-1) and collagen-I.

RESULTS

Pterygium progression was arrested in all patients. Sixty-two percent of patients had improvement of redness while 89% had reduced thickness of the lesion. VEGF, bFGF, EGF, vWF, LYVE-1 and collagen-I were all reduced in the injected samples.

CONCLUSIONS

The injection of 5 fluorouracil and Avastin act synergistically to arrest progression and induce atrophy in primary pterygium. This is related to the effect of agents on fibroblasts, collagen, and vascular tissues. Such medical intervention is a safe and viable option in the management of primary pterygium though excision of residual tissue is still required in some cases. Longer follow up is needed to ascertain whether this will reduce the recurrence rate following excision.

Simple limbal epithelial transplantation for recurrent pterygium: A case series

PURPOSE

Pterygium recurrence is a common complication of pterygium removal. Multiple surgical and medical approaches have been utilized to reduce recurrence rates. The present case series proposes a novel way to treat recurrent pterygia, by using the simple limbal epithelial transplantation (SLET) technique.

OBSERVATIONS

The cases of four patients who presented with recurrent pterygium were reviewed. In all four of the cases reported, the SLET procedure went without complication. There were no significant recurrences at each of the patient's most recent follow-up visits.

CONCLUSIONS AND IMPORTANCE

This is the first report of SLET being used as a treatment modality for recurrent pterygium. Further studies are required to more reliably demonstrate the utility of the procedure in this clinical circumstance, but our results are encouraging that in select patients, this may be a viable option in treating aggressive recurrent pterygia.

Healing of autologous conjunctival grafts in pterygium surgery

PURPOSE

To temporally study the healing of conjunctival autografts in consecutive patients following pterygium surgery.

METHODS

A case-cohort observational study. Thirty-two eyes of 28 patients who underwent pterygium surgery were included. All eyes had pterygium excision with conjunctival autografts. Twenty-seven eyes of 24 patients underwent excision of primary pterygium while five eyes of four patients had surgery for recurrent pterygium. All grafts were attached using fibrin glue. Mitomycin-C 0.04% was used intraoperatively in 25 eyes. All eyes were followed up at 1, 2, 4, 8, 12 weeks and 6 months postoperatively. Photographs were taken at each visit to monitor graft vessels, re-perfusion and healing. Main outcome measures were graft loss; re-perfusion of grafts and appearance and resolution of oedema, transudation and haemorrhage; approximation of graft edges to host bed and changes at donor site.

RESULTS

No graft tissue was lost. In all eyes, healing of autografts started with graft swelling due to oedema and transudation followed by re-perfusion injury, which manifested as swelling, variable vessels calibre, patchy or diffuse haemorrhage occurring within first week and resolving by fourth postoperative week. Graft vessels anastomose with vessels in surrounding conjunctiva and underlying episclera to re-establish blood circulation. Retraction of graft edges from surrounding conjunctiva was uncommon with rapid epithelialization of exposed (epi)sclera.

CONCLUSION

Conjunctival autografts in pterygium surgery follow a consistent healing pattern dominated by re-perfusion injury in early postoperative days. This produces dramatic changes in the autograft for which patients should be counselled before surgery. Conjunctival autografts are not at risk of falling off, losing epithelial cover or undergoing necrosis.

Tyrosine Kinase Inhibitor, Vatalanib, Inhibits Proliferation and Migration of Human Pterygial Fibroblasts

PURPOSE

Vatalanib is a small-molecule tyrosine kinase inhibitor. We investigated the effects of vatalanib on the proliferation and migration of cultured human pterygial fibroblasts (HPFs).

METHODS

Pterygium tissues were obtained after pterygium excision surgery and subjected to primary culture. HPFs were treated with vatalanib at various concentrations. Mitomycin C (MMC) was used as a positive control. Cell proliferation and migration assays were used to investigate the effects of vatalanib. Cell death was measured using flow cytometry analysis. Western blot analysis was performed to identify signaling molecules associated with the response to vatalanib.

RESULTS

Vatalanib inhibited both proliferation and migration of HPFs in a dose-dependent manner. Cell proliferation was significantly suppressed by vatalanib (10 and 100 μM) and MMC (0.004% and 0.04%) treatments. Migration assays revealed significant HPF delay when treated with vatalanib (1, 10, and 100 μM) and MMC (0.004% and 0.04%) compared with that in a negative control. Cell death analysis showed that high concentrations of vatalanib (100 μM) and MMC (0.004% and 0.04%) decreased cell numbers. Western blot analysis of vatalanib-treated cells showed vascular endothelial growth factor and transforming growth factor-β significantly reduced, but there was no alteration in p53 protein levels in HPFs.

CONCLUSIONS

These results indicate that vatalanib significantly suppressed the proliferation and migration of HPFs by decreasing vascular endothelial growth factor and transforming growth factor-β. Vatalanib showed less toxicity than that of MMC. Based on these results, vatalanib may potentially serve as a new adjuvant treatment after pterygium excision surgery.

Ocular surface changes in recurrent pterygium cases post-operatively treated with 5-fluorouracil subconjunctival injections

INTRODUCTION:

To investigate the ocular surface changes occurring in eyes with recurrent pterygium post-operatively treated with 5-fluorouracil intralesional injections.

METHODS:

Retrospective observational study of recurrent pterygium cases treated with weekly intralesional injections of 0.1 mL (5 mg) of 5-fluorouracil (10 injections). Impression cytology samples taken from the lesion, the healthy conjunctivae (inferior, superior, and contralateral to injury), and the cornea before and after treatment were analyzed. Clinical ocular characteristics (including Schirmer's test and break-up time) were evaluated during treatment.

RESULTS:

A total of 15 eyes were treated, with the mean follow-up of 27 ± 8.7 months (mean ± standard deviation). Prior to treatment initiation, the ocular surface citology over the pterygium was found to be abnormal. No epithelial cells (27%) and a lower goblet cell density (73%) compared to the healthy conjunctivae (p < 0.01) were found. Squamous metaplasia was observed to some degree in the cornea (100%), pterygium (81%) and healthy conjunctivae (73%). Following treatment, pterygium composition had changed: epithelial cell number (100%) and goblet cell density (47%) had increased (p < 0.05). Goblet cell density was also increased in healthy conjunctivae (67%; p < 0.05). The degree of squamous metaplasia decreased in the cornea (67%), pterygium (45%), and healthy conjunctivae (60%; p < 0.05). No adverse effects were reported, recurrence progression was arrested, and conjunctival redness and dry-eye severity level were decreased in all cases (p < 0.01).

DISCUSSION:

The cytology of ocular surface in recurrent pterygium is abnormal. After weekly intralesional 5-fluorouracil injections, it tends to normalize. The 5-fluorouracil compound is a safe and effective treatment to prevent pterygium recurrence.

Comparison among adjuvant treatments for primary pterygium: a network meta-analysis

PURPOSE

Pterygium is a frequent ocular disease, where the major challenge is the high level of recurrence after its surgical removal. We performed a network meta-analysis to identify, among several adjuvant treatments for primary pterygium, which is the best to prevent recurrence.

METHODS

A search was conducted using PubMed, Scientific Electronic Library Online, Latin American and Caribbean Centre on Health Sciences and Cochrane Eyes and Vision Group Trials Register between 1993 and 2015 for randomisedclinical trials (RCTs) comparing adjuvant treatments following primary pterygium surgery.

RESULTS

24 RCTs that studied 1815 eyes of 1668 patients were included and allowed direct and indirect comparison among 14 interventions through network meta-analysis. The rank from the best to worse treatment to prevent recurrence is: conjunctival autograft + ciclosporin 0.05% eye drops, bare sclera + intraoperativemitomycin C (MMC) <0.02%, bare sclera + beta therapy (2500 cGy single dose), conjunctival autograft + beta therapy (1000 cGy single dose), bare sclera + MMC 0.02% eye drops, conjunctival autograft, bare sclera + intraoperative MMC >0.02%, bare sclera + ciclosporin 0.05% eye drops, bare sclera + intraoperative 5-fluorouracil 5%, amniotic membrane transplantation, bare sclera + intraoperative MMC 0.02%, conjunctival autograft + bevacizumab 0.05% eye drops, bare sclera + bevacizumab 0.05% eye drops and bare sclera alone.

CONCLUSION

The best adjuvant treatment to prevent recurrence after primary pterygium surgery is the association of conjunctival autograft and ciclosporin 0.05% eye drops. Bare sclera technique alone should be discontinued since it is associated with high recurrence rates.

A novel graft option after pterygium excision: platelet-rich fibrin for conjunctivoplasty

PurposeTo compare the surgical results, complications, and recurrence rates of primary pterygium excision with conjunctival autografts (CA) vs platelet-rich fibrin (PRF) grafts.Patients and methodsA total of 35 eyes of 35 patients with primary pterygium were included in the study. The patients underwent excision of pterygium followed by closure of the bare sclera by CA (group 1, n=20) vs PRF grafts (group 2, n=15). The PRF was generated from the patients' own whole-blood sample by centrifugation and pressing. The surgery times, intra/postoperative complications, recurrence rates of pterygium, and changes in visual acuity (VA) were evaluated and compared within groups.ResultsThe mean follow-up period was 14.3±6.5 months (6-24 months). The mean preoperative and postoperative VAs were same (20/25) (P=0.204). The mean surgery time was shorter in group 2 (22.1±1.9 min) compared to group 1 (33.8±7.8 min) (P=0.001). The recurrence was observed only in one (6.6%) case of group 2, while none of the cases showed recurrence in group 1. Graft loss was observed in 2 (10%) cases in group 1, and 1 (6.6%) case in group 2. No other intra/postoperative complications such as tear in the graft, excessive bleeding, scleral necrosis, graft necrosis, pannus formation, or symblepharon occurred in both groups.ConclusionsThis preliminary study showed encouraging results of the application of PRF for conjuntivoplasty after pterygium excision. The use of PRF in pterygium surgery is a simple, easily applicable, and a promising method with low rates of recurrence and complications.

The role of ultraviolet radiation in the pathogenesis of pterygia (Review)

Pterygium is a common ophthalmic disease affecting humans only. Extensive epidemiological data have demonstrated a causative effect of chronic ultraviolet (UV) radiation on pterygia. Progress has been made in determining the origin of pterygia, their nasal predilection and wing‑shaped appearance, and the roles of UV radiation in the initiation and the development of pterygia. In the present review, the current understanding of the involvement of UV radiation in the pathogenesis of pterygia is summarized. This involvement includes the alteration of limbal stem cells and fibroblasts that contribute to the initiation of pterygia and the induction of various pro‑inflammatory cytokines, growth factors and matrix metalloproteinases that promote the progression of pterygia. Further elucidation of the roles of UV radiation in the pathogenesis of pterygia may help to encourage individuals at risk of developing pterygia to take preventive measures and aid researchers in the development of novel targeted therapeutic agents to treat pterygia.

Effect of intralesional 5 fluorouracil injection in primary pterygium

Objective:

To determine mean change in visual acuity, corneal astigmatism and clinical appearance of pterygium after intralesional injection of 5-Fluorouracil.

Methods:

This was a Quasi experimental study conducted at Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan from June 2014 to May 2015. Total 68 eyes of 54 patients were included in the study. Patients were treated by injecting 0.1 ml of 5-FU (5mg) weekly injections for 04 weeks. All the patients underwent ophthalmic clinical examination that included Uncorrected distant visual acuity (UCVA), corrected distant visual acuity (CDVA), keratometery with Auto Ref-keratometer (RK-F1, Canon) and slit lamp examination before and 04 weeks after the last injection.

Results:

Total 68 eyes of 54 patients (18 females and 36 males) were treated with intralesional injection of 5 FU. Out of total, 30 were right eyes while 38 were left eyes. Age of patients ranged from 23 to 53 years with mean age of 39.2 ± 4.90 years. Mean UCVA and corneal astigmatism before treatment were 0.162 ± 0.167 and 2.12 ± 1.53 respectively while the same parameters 04 weeks after last injection of 5 FU were 0.166 ± 0.168 and 1.92±1.45 respectively. The magnitude of induced change in astigmatism was (0.235 ± 1.35). Ninety seven percent of the patients showed improvement in clinical appearance.

Conclusion:

Intralesional 5-FU injection results in significant clinical and cosmetic improvement of primary pterygium.

Clinical analysis of risk factors contributing to recurrence of pterygium after excision and graft surgery

AIM

To find the risk factors related to the reproliferation of the pterygial tissue after excision and graft surgery.

METHODS

Charts of 130 eyes of 130 patients who had pterygial excision from March 2006 to April 2011 were reviewed. Preoperative pterygium morphology, surgical methods, and adjunctive treatments were statistically analyzed for their relationship with recurrence.

RESULTS

During the follow-up period, recurrence was observed in 20 eyes (15.4%). None of the preoperative morphologic features were affected the rate of the recurrence. However, an age < 40y [P =0.085, odds ratio (OR) 3.609, 95% confidence interval (CI) 0.838-15.540] and amniotic membrane graft instead of conjunctival autograft (P =0.002, OR 9.093, 95% CI 2.316-35.698) were statistically significant risk factors for recurrence. Multivariate analysis revealed that intraoperative mitomycin C (MMC) (P=0.072, OR 0.298, 95% CI 0.080-1.115) decreased the rate of recurrence.

CONCLUSION

Younger age is a risk factor for reproliferation of pterygial tissue after excision and amniotic membrane transplantation (AMT) are less effective in preventing recurrence of pterygium after excision based on the comparison between conjunctival autograft and AMT. Intraoperative MMC application and conjunctival autograft reduce recurrence.

Molecular Basis of Pterygium Development

Pterygium pathogenesis is mainly related to UV light exposure. However, the exact mechanisms by which it is formed have not been elucidated. Clinical advances in surgical treatment use conjunctival autografts and amniotic membranes in combination with adjuvant therapies, including mitomycin C, β-radiation, and 5-fluoroacil, to reduce recurrence. Several studies aim to unveil the molecular mechanisms underlying pterygium growth and proliferation. They demonstrate the role of different factors, such as viruses, oxidative stress, DNA methylation, apoptotic and oncogenic proteins, loss of heterozygosity, microsatellite instability, inflammatory mediators, extracellular matrix modulators, lymphangiogenesis, cell epithelial-mesenchymal transition, and alterations in cholesterol metabolism in pterygium development. Understanding the molecular basis of pterygium provides new potential therapeutic targets for its prevention and elimination. This review focuses on providing a broad overview of what is currently known regarding molecular mechanisms of pterygium pathogenesis.