Assessing genetic and environmental components for pterygium: a nationwide study in Taiwan.

This study aims to estimate the familial risks of pterygium and assess its relative contributions to environmental and genetic factors using the 2000-2017 Taiwan National Health Insurance Research Database. The marginal Cox's model and the polygenic liability model were made. In Taiwan, the prevalence rate of pterygium in 2017 was 1.64% for individuals with affected first-degree relatives, higher than the general population (1.34%). The adjusted relative risk (RR) for pterygium was highest for twins of the same sex (15.54), followed by siblings of the same sex (4.69), offsprings (3.39), siblings of the different sex (2.88), spouse (2.12), parents (1.86), twins of the different sex (1.57), respectively. The phenotypic variance of pterygium was 21.6% from additive genetic variance, 24.3% from common environmental factors shared by family members, and 54.1% from non-shared environmental factors, respectively. Sensitivity analysis by restricting those with surgical pterygium reveals that aRRs and the three components were similar to those of the overall pterygium. In summary, the prevalence rate of pterygium was higher for individuals with affected first-degree relatives than for the general population. The non-shared environmental factors account for half of the phenotypic variance of pterygium; genetic and shared environmental factors explain the rest.

Contribution of Radiation Sensitive Protein 51 Genotypes to Pterygium Risk in a Taiwanese Population.

BACKGROUND/AIM: In current literature, there is a notable lack of studies investigating the role of radiation-sensitive protein 51 (RAD-51) in pterygium diagnosis. Nevertheless, reports indicate elevated expression levels of RAD-51 among recurrent pterygium cases compared to those with primary pterygium. However, the genomic involvement of RAD-51 has yet to be explored in any population. This study aimed to assess the contribution of RAD-51 genotypes to pterygium risk in a representative Taiwanese population. MATERIALS AND METHODS: RAD-51 rs1801320 genotyping was successfully conducted in a Taiwanese cohort comprising 140 pterygium cases and 280 non-pterygium controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. RESULTS: The distribution of RAD-51 rs1801320 genotypes (GG, CG, and CC) in the pterygium group (70.0%, 25.7%, and 4.3%, respectively) did not significantly differ from that in the non-pterygium group (73.6%, 23.6%, and 2.8% for GG, CG, and CC genotypes, respectively; p for trend=0.6337). Carriers of the variant CG and CC RAD-51 rs1801320 genotypes exhibited 1.15- and 1.58-fold increased pterygium risk, respectively (95%CI=0.72-1.84 and 0.53-4.67, p=0.6552 and p=0.5914, respectively). In the dominant model, there appeared to be a slight association between variant genotypes CG and CC and pterygium risk (OR=1.19, 95%CI=0.76-1.87, p=0.0223). Allelic analysis revealed that the RAD-51 rs1801320 variant C allele was not significantly linked to pterygium risk (17.1% versus 14.6%, OR=1.20, 95%CI=0.82-1.78, p=0.3991). CONCLUSION: Variant genotypes at RAD-51 rs1801320 were firstly identified to associate with susceptibility to pterygium among Taiwanese individuals. Nonetheless, these findings warrant validation in larger and more diverse populations.

Management of pterygium: our experience and a simplified treatment algorithm.

Aim: To explore various approaches in the management of pterygium and to propose a simplified treatment algorithm for its surgical management. Methods: A retrospective analysis of 9219 eyes was done. Group I included patients with primary single-head pterygium, most undergoing pterygium excision with conjunctival autograft (CAG). CTG-P (Conjunctival tissue graft from pterygium), AMG (Amniotic membrane graft), and inferior CAG were done in the remaining patients in this group in which conventional conjunctival autograft was a relative contraindication. Group II included patients with primary double-head pterygium who underwent vertical/horizontal split CAG, with/without limbal orientation, Inferior + Superior CAG, CTG-P, and CAG + CTG-P. Group III included patients with recurrent single-head pterygium who underwent ER (Extended resection) + LCAG (Limbal conjunctival autograft), LCAG + MMC (Mitomycin-C), CAG + MMC (Mitomycin-C) and CAG. Group IV included patients with recurrent double-head pterygium who underwent split LCAG and CAG + SLET. Results: All the four groups reported a low incidence of pterygium recurrence. Recurrence was observed at a rate of 0.47%, 3.63%, 2.86%, and 7.69% in Group I, Group II, Group III and Group IV respectively. Discussion: We mainly aimed to get minimal recurrence and good cosmetic outcomes. In double-head pterygium, we could achieve good and comparable outcomes with horizontal or vertical split CAG, with or without maintaining limbal orientation. Similarly, Inferior + Superior CAG, CTG-P, CAG+CTG-P, and AMG also showed low recurrence rates. In recurrent pterygium, ER + LCAG/CAG, with/without adjuncts like MMC showed low recurrence rates. Thus, all of these methods were found to be viable options. The main strength of our study, compared to previous studies on pterygium was its large sample size and long duration of follow-up. Conclusion: All the methods we studied had a low recurrence rate. We have formulated a treatment algorithm for pterygium management based on our outcomes. Abbreviations: CAG = Conjunctival autograft, CTG-P = Conjunctival tissue graft from pterygium, ER = Extended resection, MMC = Mitomycin-C.

The effect of cyclosporine a in pterygium surgery using fibrin glue.

BACKGROUND/OBJECTIVES: To evaluate the effect of topical cyclosporine A (CsA) 0.05% in patients with pterygium surgery using fibrin glue (FG). SUBJECTS/METHODS: Patients with primary nasal pterygium were retrospectically analyzed and categorized into two groups: Group 1 with 41 eyes from 38 patients as a control group and group 2 with 39 eyes from 36 patients who received topical CsA twice a day for 6 months. Patients were assessed for recurrence rate, tear film parameters, side effects, and complications at postoperative intervals of 1-7 days; 1st, 3rd, 6th and 12th months. The follow-up period was 1 year. RESULTS: The two groups were age (p = 0.934) and sex (p = 0.996) matched. CsA drop was discontinued in one patient due to burning sensation and conjunctival hyperemia after 1 week. There was no statistically significant difference between the mean preoperative and postoperative 1st year Schirmer I and tear break-up time (TBUT) values in group 1 (p = 0.136; p = 0.069). Although the difference between the mean preoperative and postoperative 1st year TBUT values in group 2 was not statistically different (p = 0.249), Schirmer I results were higher postoperatively (p = 0.003). There was no statistically significant difference between preoperative Schirmer (p = 0.496), postoperative Schirmer (p = 0.661), preoperative TBUT (p = 0.240) and postoperative TBUT (p = 0.238) results of the two groups. Recurrence was observed in only one patient from group 1. CONCLUSION: No recurrent pterygium cases were observed in group 2. Schirmer I values were higher postoperatively in group 2; thus,topical CsA treatment may improve lacrimal secretion and be effective after pterygium surgery with FG.

Integrative analysis of ex vivo studies and microarray reveals the novel inhibitor effects of trehalose on the pathogenesis of pterygium.

Pterygium is a frequent eye surface condition that is characterized by a high rate of proliferation, fibrovascular development, cellular migration, corneal infiltration, and angiogenesis. We investigated that ex vivo primary pterygium and conjunctival cell cultures were generated to analyze the effect of trehalose on cellular proliferation. After trehalose treatment, we performed microarray analysis to evaluate changes in the mRNA profile. We analyzed gene ontology (GO) and KEGG pathways to identify hub genes that changed expression levels after treatment and were associated with pterygium development. We selected three genes to verify their expression levels using qRT-PCR. The study also evaluated the impact of trehalose treatment on cell migration through a wound-healing assay. Our results suggested that pterygium cell proliferation was inhibited in a dose-dependent manner by trehalose. 2354 DEG were identified in pterygium and conjunctiva cells treated with trehalose compared to untreated groups. Functional enrichment analysis showed that differentially expressed mRNAs are involved in proliferation, vasculature development, and cell migration. We identified ten hub genes including upregulated (RANBP3L, SLC5A3, RERG, ANKRD1, DHCR7, RAB27B, GPRC5B, MSMO1, ASPN, DRAM1) and downregulated (TNC, PTGS2, GREM2, NPTX1, NR4A1, HMOX1, CXCL12, IL6, MYH2, TXNIP). Microarray analysis and functional investigations suggest that trehalose affects the pathogenesis of pterygium by modifying the expression of genes involved in crucial pathways related to cell function.

Collagen-Based Artificial Cornea for Lamellar Keratoplasty: An Early Case Report.

PURPOSE: The aim of this study was to evaluate Viscoll collagen membrane (VCM) for lamellar keratoplasty. METHODS: A 54-year-old man with grade 4 recurrent pterygium underwent lamellar keratoplasty using VCM as the graft material. Standard keratoplasty postoperative treatments, including topical antibiotic-corticosteroid and artificial tears, were administered. RESULTS: Complete graft epithelialization was achieved after 4 days of the surgery. Follow-up at 9 months showed no pterygium recurrence as well as good integration of the VCM graft into the surrounding tissues with preserved transparency. CONCLUSIONS: This case demonstrated that VCM possesses great potential as an alternative to the human donor cornea for lamellar keratoplasty; however, the application of VCM for lamellar keratoplasty still needs additional evaluation.

[Current possibilities for the diagnosis and treatment of pterygium]. / Sovremennye vozmozhnosti diagnostiki i lecheniya pterigiuma.

Pterygium is a common inflammatory-proliferative disease characterized by the invasion of degeneratively altered fibrovascular tissue into the cornea. This literature review analyzes the etiological factors and pathogenetic concepts of its development, describes modern methods of diagnostics and surgical treatment of pterygium, and pays particular attention to the assessment of structural and functional changes in the cornea occurring during the growth of pterygium and after its excision.

Multi-System-Level Analysis with RNA-Seq on Pterygium Inflammation Discovers Association between Inflammatory Responses, Oxidative Stress, and Oxidative Phosphorylation.

A pterygium is a common conjunctival degeneration and inflammatory condition. It grows onto the corneal surface or limbus, causing blurred vision and cosmetic issues. Ultraviolet is a well-known risk factor for the development of a pterygium, although its pathogenesis remains unclear, with only limited understanding of its hereditary basis. In this study, we collected RNA-seq from both pterygial tissues and conjunctival tissues (as controls) from six patients (a total of twelve biological samples) and retrieved publicly available data, including eight pterygium samples and eight controls. We investigated the intrinsic gene regulatory mechanisms closely linked to the inflammatory reactions of pterygiums and compared Asian (Korea) and the European (Germany) pterygiums using multiple analysis approaches from different perspectives. The increased expression of antioxidant genes in response to oxidative stress and DNA damage implies an association between these factors and pterygium development. Also, our comparative analysis revealed both similarities and differences between Asian and European pterygiums. The decrease in gene expressions involved in the three primary inflammatory signaling pathways-JAK/STAT, MAPK, and NF-kappa B signaling-suggests a connection between pathway dysfunction and pterygium development. We also observed relatively higher activity of autophagy and antioxidants in the Asian group, while the European group exhibited more pronounced stress responses against oxidative stress. These differences could potentially be necessitated by energy-associated pathways, specifically oxidative phosphorylation.

Expression of CD44, PCNA and E-cadherin in pterygium tissues.

PURPOSE: Pterygium is a common ocular surface disease defined by fibrovascular conjunctival growth extending onto the cornea. However, its pathogenesis remains unclear. This study aimed to determine the role of CD44, proliferating cell nuclear antigen (PCNA), and E-cadherin in pterygium formation and recurrence. METHODS: Sixty patients with pterygium participated in the study, and we collected conjunctival samples from 30 patients to form a control group. CD44, PCNA, and E-cadherin expressions in surgically excised pterygium were compared with tissue samples from the control group. RESULTS: We observed that the percentages of CD44 and PCNA were statistically higher in the primary pterygium group and recurrent pterygium group than in the control group (P < 0.001 and P < 0.001, respectively). Conversely, E-cadherin values were statistically higher in the control group than in the primary and recurrent pterygium groups (P = 0.013 and P < 0.001, respectively). CONCLUSION: Cell proliferation and cell adhesion factors may play important roles in the pathogenesis of pterygium.

Congenital pterygium with anterior segment dysgenesis: rare ocular manifestation in Rubinstein-Taybi syndrome.

Pterygium is a benign, wing-shaped fibrovascular overgrowth of subconjunctival tissue that can encroach over the cornea. This condition usually occurs in individuals aged 20-40 years but is rarely seen in children. We report a case of an infant with Rubenstein-Taybi syndrome presenting with nebulo-macular corneal opacity and congenital pterygium. On examination under anaesthesia, bilateral infero-nasal nebulo-macular corneal opacity (6 × 5 mm) with a whitish pink tissue originating from nasal bulbar conjunctiva was noticed. The probe test was negative for this tissue. To the best of our knowledge, only two other cases of congenital pterygium have been reported in the literature. The presence of this anomaly supports the hypothesis of genetic factors having a role in the development of pterygium.

Risk factors for pterygium: Latest research progress on major pathogenesis.

A pterygium is a wedge-shaped fibrovascular growth of the conjunctiva membrane that extends onto the cornea, which is the outer layer of the eye. It is also known as surfer's eye. Growth of a pterygium can also occur on the either side of the eye, attaching firmly to the sclera. Pterygia are one of the world's most common ocular diseases. However, the pathogenesis remains unsolved to date. As the pathogenesis of pterygium is closely related to finding the ideal treatment, a clear understanding of the pathogenesis will lead to better treatment and lower the recurrence rate, which is notably high and more difficult to treat than a primary pterygium. Massive studies have recently been conducted to determine the exact causes and mechanism of pterygia. We evaluated the pathogenetic factors ultraviolet radiation, viral infection, tumor suppressor genes p53, growth factors, oxidative stress, apoptosis and neuropeptides in the progression of the disease. The heightened expression of TRPV1 suggests its potential contribution in the occurrence of pterygium, promoting its inflammation and modulating sensory responses in ocular tissues. Subsequently, the developmental mechanism of pterygium, along with its correlation with dry eye disease is proposed to facilitate the identification of pathogenetic factors for pterygia, contributing to the advancement of understanding in this area and may lead to improved surgical outcomes.

Modified sutureless and glue-free method versus conventional sutures for conjunctival autograft fixation in primary pterygium surgery: a systematic review and meta-analysis.

BACKGROUND: Pterygium is a common ocular surface disorder that requires surgical intervention for treatment. Conjunctival autografts are preferred over simple excision due to lower recurrence rates. This systematic review and meta-analysis compared the modified sutureless glue-free (MSGF) method with conventional sutures (CS) for conjunctival autograft fixation in primary pterygium surgery. METHODS: A comprehensive search was conducted in MEDLINE, Embase, CENTRAL, Google Scholar and ClinicalTrials.gov for randomised controlled trials (RCTs) comparing MSGF and CS conjunctival autografts. Outcome measures included operation time, recurrence and postoperative complications. Standardised mean difference (SMD) and risk ratio (RR) were used for continuous and dichotomous outcomes, respectively. RESULTS: 11 RCTs involving 833 participants were included. The analysis revealed that MSGF had a significantly shorter operation time compared with CS (SMD -3.704, 95% CI -5.122 to -2.287, p<0.001). CS was associated with a higher risk of foreign body sensation (RR 0.22, 95% CI 0.06 to 0.74, p=0.01). MSGF was associated with a higher risk of graft dehiscence (RR 9.01, 95% CI 2.74 to 29.68, p=0.000) and graft retraction (RR 2.37, 95% CI 1.17 to 4.77, p=0.02). No significant differences were found in recurrence, graft haemorrhage, granuloma, Dellen and conjunctival oedema. CONCLUSION: Using the MSGF technique in conjunctival autograft fixation for pterygium surgery reduces operation time by relying solely on the patient's blood for fixation. However, it increases the risk of graft dehiscence and retraction. However, CS is linked to a higher likelihood of experiencing foreign body sensations. Understanding the learning curve and surgeon familiarity with novel techniques is crucial for optimising patient care and surgical outcomes, while individualised decision-making is necessary considering the advantages and disadvantages of each approach. Further research is warranted to minimise complications and optimise surgical outcomes.

RIPK3 and RIPK1 gene expression in pterygium: unveiling molecular insights into pathogenesis.

BACKGROUND: Pterygium, characterized by the abnormal proliferation of epithelial cells, matrix remodeling, vascularization, and lesion migration, is a prevalent ocular surface disease involving the growth of fibrovascular tissue on the cornea. Despite the unclear underlying causes of pterygium, numerous investigations have indicated the involvement of cell death pathways in the regulation of cell cycle dynamics. Consequently, the objective of this study was to assess the expression levels of necroptosis markers in individuals diagnosed with pterygium, aiming to shed light on the potential role of necroptosis in the pathogenesis of this condition. METHODS: This study aimed to investigate the expression patterns of receptor-interacting serine/threonine kinase 3 (RIPK3) and receptor-interacting serine/threonine kinase 1 (RIPK1) genes in pterygium tissues. 41 patients undergoing pterygium excision surgery were recruited. Resected pterygium samples and normal conjunctival tissues were collected, and RIPK3 and RIPK1 mRNA levels were measured using quantitative real-time PCR. RESULTS: Our findings reveal that the expression of RIPK3 is significantly increased in samples obtained from individuals with pterygium. However, no significant alterations were observed in the expression of RIPK1 in these samples. Results showed significantly higher RIPK3 expression in pterygium tissues compared to controls. Moreover, increased RIPK3 levels correlated negatively with pterygium recurrence rates. CONCLUSIONS: These findings suggest RIPK3 may play a protective role against pterygium recurrence through necroptosis.

Functional assessment of a novel biallelic MYH3 variation causing CPSKF1B (contractures, pterygia, and spondylocarpotarsal fusion syndrome1B).

BACKGROUND: The MYH3-associated myosinopathies comprise a spectrum of rare neuromuscular disorders mainly characterized by distal arthrogryposis with or without other features like pterygia and vertebrae fusion. CPSKF1B (contractures, pterygia, and spondylocarpotarsal fusion syndrome1B) is the only known autosomal recessiveMYH3-associated myosinopathy so far, with no more than two dozen cases being reported. MATERIALS AND METHODS: A boy with CPSKF1B was recruited and subjected to a comprehensive clinical and imaging evaluation. Genetic detection with whole-exome sequencing (WES) was performed on the patient and extended family members to identify the causative variation. A series of in silico and in vitro investigations were carried out to verify the pathogenicity of the two variants of the identified compound heterozygous variation. RESULTS: The patient exhibited moderate CPSKF1B symptoms including multiarticular contractures, webbed neck, and spondylocarpotarsal fusion. WES detected a compound heterozygous MYH3 variation consisting of two variants, namely NM_002470.4: c.3377A>G; p. (E1126G) and NM_002470.4: c.5161-2A>C. It was indicated that the NM_002470.4: c.3377A>G; p. (E1126G) variant mainly impaired the local hydrogen bond formation and impacted the TGF-B pathway, while the NM_002470.4: c.5161-2A>C variant could affect the normal splicing of pre-mRNA, resulting in the appearance of multiple abnormal transcripts. CONCLUSIONS: The findings of this study expanded the mutation spectrum of CPSKF1B, provided an important basis for the counseling of the affected family, and also laid a foundation for the functional study of MYH3 mutations.

[Modified mini-SLET for treatment of complex cases in pterygium surgery]. / Modifizierte Mini-SLET zur Behandlung von komplexen Fällen in der Pterygiumchirurgie.

BACKGROUND: The major problem associated with the benign but destructive growing pterygium is the high recurrence rate. A new surgical technique to lower recurrence rates is minor ipsilateral simple limbal epithelial transplantation (mini-SLET), where the regeneration potential of limbal stem cells is used in combination with amniotic membrane transplantation (AMT) for surgical reconstruction. The aim of this study is to assess the surgical outcome of the mini-SLET technique with tenonectomy, mitomycin C, and AMT as used in the authors' hospital. MATERIALS AND METHODS: A total of 16 eyes from 15 patients undergoing mini-SLET after surgical pterygium removal with tenonectomy, mitomycin C, and AMT were analyzed retrospectively. Two different groups of pterygia were enrolled: group 1 included recurrent pterygia (n = 10) and group 2 comprised primary large pterygia such as double-head pterygia (n = 6). In addition to assessment of best corrected visual acuity and compete ophthalmological examination, preoperative slip-lamp examination with photo documentation served to calculate the corneal size of the pterygium head using VISUPAC software (Zeiss, Oberkochen, Germany). Postoperatively, best corrected visual acuity and slit-lamp examination were routinely evaluated. The surgical outcome was defined by the postoperatively achieved best corrected visual acuity, restoration of the ocular surface, recurrence rate, and rate of postoperative complications. RESULTS: Median follow-up in all patients was 27 months; in groups 1 and 2 it was 30.7 and 25.3 months, respectively. No recurrence developed in 15 eyes (93.75%). Only one group 1 patient (6.25%) suffered a recurrent lesion after 10 months. Postoperatively, logMAR visual acuity did not change significantly. During follow-up, complications were limited to one case of early wound dehiscence. CONCLUSION: Mini-SLET in combination with tenonectomy, mitomycin C, and AMT enables good surgical reconstruction of the ocular surface, and almost complete healing in the sense of restitutio ad integrum is possible. The results of the present study have shown the technique's effectiveness for recurrence prevention.

Evaluation of scleral thickness in patients with pterygium.

OBJECTIVES: To evaluate scleral thickness measurements of pterygium patients using anterior segment optical coherence tomography (AS-OCT) and to compare them with healthy individuals. MATERIAL AND METHODS: Scleral thickness was measured from 2, 4, 6 mm posterior to the scleral spur with AS-OCT (Swept Source OCT Triton, Topcon, Japan) in 4 quadrants (superior, inferior, nasal and temporal). RESULTS: Eyes with pterygium were determined as Group 1, and contralateral eyes without pterygium were determined as Group 2. Healthy controls were determined as Group 3. In the measurements made from 4 mm posterior, no significant difference was found between Group 1 and Group 2 in any quadrants (p > 0.05). In all measurements made from 4 mm posterior to the scleral spur, scleral thickness was found to be significantly higher in Group 1 compared to Group 3 (p < 0.05). Measurements made from 2 mm posterior to the scleral spur in Group 1 was found to be significantly higher in the superior and temporal quadrants compared to Group 3 (p = 0.05), while no significant difference was found in the nasal and inferior quadrants (p > 0.05). When Group 2 and Group 3 were compared, scleral thickness measurements made from 4 mm posterior to the scleral spur was significantly thicker in all quadrants in Group 2 (p > 0.05). CONCLUSION: Scleral thickness was found to be higher in pterygium patients compared to healthy controls, especially when measured from 4 mm posterior to the scleral spur. It has been predicted that high scleral thickness may be associated with high fibroblast activity in subconjunctival structures, and this may predispose to pterygium.

Herpes Simplex Keratitis as a Complication of Pterygium Surgery.

BACKGROUND Infectious keratitis after pterygium surgery is a rare but potentially devastating complication. The present study presents 5 cases of herpes simplex keratitis (HSK) after pterygium surgery. CASE REPORT This study was conducted in our clinic in a 5-year period from February 2017 to September 2021. The 5 patients were men, aged between 42 and 73 years, with no prior history of herpes simplex virus (HSV) infections. Symptoms appeared near 1 month (median 30 days, range 10 to 70 days) after primary pterygium surgery. Diagnosis was based on clinical symptoms and laboratory test results, such as tear HSV-sIgA, corneal tissue polymerase chain reaction, and next-generation sequencing of metagenomics. The epithelial (1/5) and stromal (4/5) subtypes of HSK were identified. The patients received topical ganciclovir gel, immunosuppressive eyedrops, and oral acyclovir tablets, along with additional surgical interventions if necessary. Three were healed with conservative therapy, 1 eye required amniotic membrane transplantation due to corneal melt, and 1 was perforated and followed by corneal grafting. Finally, a literature review of previous publications on HSK after ocular surgeries was conducted. CONCLUSIONS HSK is a rare but serious complication that can arise after uneventful pterygium surgery. It is worthy of attention that both epithelial and stromal forms can occur. Timely diagnosis and treatment are crucial to prevent unfavorable outcomes. Consequently, routine corneal fluorescein staining, tear sIgA examination, and corneal scraping for polymerase chain reaction or next-generation sequencing of metagenomics should be performed in any suspected cases.