Variations of pterygium prevalence by age, gender and geographic characteristics in China: A systematic review and meta-analysis

Single-cell RNA sequencing reveals the complex cellular niche of pterygium

PURPOSE

Pterygium is a vision-threatening conjunctival fibrovascular degenerated disease with a high global prevalence up to 12 %, while no absolute pharmacotherapy has been applied in clinics. In virtue of single-cell RNA sequencing (scRNA-seq) technique, our study investigated underlying pathogeneses and potential therapeutic targets of pterygium from the cellular transcriptional level.

METHODS

A total of 45605 cells from pterygium of patients and conjunctiva of normal controls (NC) were conducted with scRNA-seq, and then analyzed via integrated analysis, pathway enrichment, pseudotime trajectory, and cell-cell communications. Besides, immunofluorescence and western blot were performed in vivo and in vitro to verify our findings.

RESULTS

In brief, 9 major cellular types were defined, according to canonical markers. Subsequently, we further determined the subgroups of each major cell lineages. Several newly identified cell sub-clusters could promote pterygium, including immuno-fibroblasts, epithelial mesenchymal transition (EMT)-epithelial cells, and activated vascular endothelial cells (activated-vEndo). Besides, we also probed the enrichment of immune cells in pterygium. Particularly, macrophages, recruited by ACKR1+activated-vEndo, might play an important role in the development of pterygium by promoting angiogenesis, immune suppression, and inflammation.

CONCLUSION

An intricate cellular niche was revealed in pterygium via scRNA-seq analysis and the interactions between macrophages and ACKR1+ activated-vEndo might be the key part in the development of pterygia.

Effects of chemokine receptor CCR7 in the pathophysiology and clinical features of the immuno-inflammatory response in primary pterygium

OBJECTIVE

Chemokine receptor 7 (CCR7) has been considered a critical biomarker in inflammation and the immune response; however, little is known about CCR7 in pterygia. This study aimed to investigate whether CCR7 participates in the pathogenesis of primary pterygia and how CCR7 affects the progression of pterygia.

METHODS

This was an experimental study. Slip-lamp photographs of 85 pterygium patients were used to measure the width, extent, and area of pterygia with computer software. Pterygium blood vessels and general ocular redness were quantitatively analyzed with a specific algorithm. The expression of CCR7 and its ligands C-C motif ligand 19 (CCL19) and C-C motif ligand 21 (CCL21) in control conjunctivae and excised pterygia collected during surgery were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence staining. The phenotype of CCR7-expressing cells was identified by costaining for major histocompatibility complex II (MHC II), CD11b or CD11c.

RESULTS

The CCR7 level was significantly increased by 9.6-fold in pterygia compared with control conjunctivae (p = 0.008). The higher the expression of CCR7 was, the more blood vessels appeared in pterygia (r = 0.437, p = 0.002) and the more general ocular redness was (r = 0.51, p < 0.001) in pterygium patients. CCR7 was significantly associated with pterygium extent (r = 0.286, p = 0.048). In addition, we found that CCR7 colocalized with CD11b, CD11c or MHC II in dendritic cells, and immunofluorescence staining showed that CCR7-CCL21 is a potential chemokine axis in pterygium.

CONCLUSIONS

This work verified that CCR7 impacts the extent of primary pterygia invading the cornea and inflammation at the ocular surface, which may provide a possibility for a further in-depth understanding of the immunological mechanism in pterygia.

Amniotic membrane transplantation and conjunctival autograft combined with mitomycin C for the management of primary pterygium: A systematic review and meta-analysis

Background

Pterygium is a common ocular surface disease. Recurrence is the greatest concern in the treatment of pterygium. Thus, a standardized and effective treatment modality with minimal risk for complications is needed for the management of pterygium. The aim of this systematic review and meta-analysis was to evaluate different tissue grafting options, including conjunctival autograft (CAG) with mitomycin C (MMC), CAG alone, and amniotic membrane transplantation (AMT), for the management of primary pterygium.

Methods

We searched the MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases for relevant studies. We included randomized controlled trials (RCTs) in which CAG + MMC and AMT were compared with surgical excision with CAG alone for the treatment of primary pterygium. The rates of recurrence and adverse events reported in the studies were also evaluated. Risk ratio (RR) was used to represent dichotomous outcomes. The data were pooled using the inverse variance weighting method. The quality of the evidence derived from the analysis was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Risk of bias was assessed using the revised Cochrane risk-of-bias tool for randomized trials.

Results

Twelve RCTs (n = 1144) were deemed eligible and included for analysis. Five RCTs had a low risk of bias, five had some concerns, and two had a high risk of bias. Subgroup analysis showed a statistically significant reduction in the rate of pterygium recurrence after CAG + MMC (RR = 0.12; 95% confidence interval [CI], 0.02–0.63). This outcome was rated as high-quality evidence according to the GRADE criteria. There were insignificant differences between the rates of recurrence after AMT and CAG (RR = 1.51; 95% CI, 0.63–3.65). However, this result was rated as low-quality evidence. Regarding adverse events, patients treated using AMT showed significantly lower rates of adverse events than those treated using CAG (RR = 0.46; 95% CI, 0.22–0.95). However, this finding was rated as low-quality evidence as well. CAG + MMC showed a safety profile comparable to that of surgical excision with CAG alone (RR = 1.81; 95% CI, 0.40–8.31). This result was also rated as low-quality evidence.

Conclusion

A single intraoperative topical application of 0.02% MMC during excision of pterygium followed by CAG has significantly shown to decrease the rate of pterygium recurrence to 1.4% with no severe complications.

Environmental exposures to lead, cadmium, and mercury and pterygium in Korean adults

Pterygium, one of the most common eye disorders, is an abnormal fibrovascular proliferation extending from the conjunctiva to the cornea. The mechanism of development in pterygium has not been fully elucidated; however, oxidative stress is suggested to be one of the major causes. Heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg) enter the human body and induce oxidative stress. However, no study has investigated the association of these heavy metals with pterygium. Therefore, this study aimed to evaluate the associations of environmental exposures to Pb, Cd, and Hg with pterygium in the Korean general adults. We analyzed data from 6,587 adults (≥ 20 years of age) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011. Pterygium was diagnosed as the presence of a wing-shaped fibrovascular growth. The exposures of Pb, Cd, and Hg were estimated by measuring blood concentrations. The prevalence of pterygium in this study population was 4.0% (348 subjects). After adjusting for potential confounders, the Pb level in blood was found to have a significant dose-dependent association with pterygium (p for trend = 0.001), and its highest quintile (vs. the lowest) had an odds ratio (OR) of 2.22 (95% CI: 1.30, 3.78) for pterygium. The Hg level in blood in the second quintile (vs. the lowest) had an OR of 1.64 (95% CI: 1.04, 2.59) for pterygium. In conclusion, this study suggests that environmental exposures to Pb and Hg in the Korean general adults may be related to the development of pterygium.

Vitamin D, the Vitamin D Receptor, Calcitriol Analogues and Their Link with Ocular Diseases

The global prevalence of eye diseases continues to grow, bringing with it a reduction in the activity levels and quality of life of patients, and partial or complete blindness if left untreated. As such, there is considerable interest in identifying more effective therapeutic options and preventive agents. One such agent is vitamin D, known to have a range of anti-cancer, anti-angiogenic, anti-inflammatory and anti-oxidative properties, and whose deficiency is linked to the pathogenesis of a range of cardiovascular, cancer, and inflammatory diseases. This review presents the current stage of knowledge concerning the link between vitamin D and its receptor and the occurrence of eye disease, as well as the influence of analogues of calcitriol, an active metabolite of vitamin D. Generally, patients affected by various ocular disorders have vitamin D deficiency. In addition, previous findings suggest that vitamin D modulates the course of eye diseases and may serve as a marker, and that its supplementation could mitigate some disorders. However, as these studies have some limitations, we recommend further randomized trials to clarify the link between vitamin D and its activity with eye disease.

Evaluation of JUN, FN1 and LAMB1 polymorphisms in pterygium in a Chinese Han population

PURPOSE

To explore the underlying molecular mechanism of pterygium and identify the key genes regulating the development of pterygium.

METHODS

Differentially expressed mRNAs were obtained from the Gene Expression Omnibus (GEO) database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using the DAVID (http://david.abcc.ncifcrf.gov/). The differential expressions of hub genes were verified using the reverse transcription-real-time fluorescent quantitative PCR (RT-qPCR). The function of the hub genes was further confirmed based on associations between the single nucleotide polymorphisms (SNPs) in hub genes and pterygium. The genotyping results were analyzed using SNPStats online software in five gene models, including codominant, dominant, recessive, overdominant, and log-additive. Five gene models were analyzed using SNPStats.

RESULTS

We found that 240 genes were significantly differentially expressed. Functional enrichment analysis showed that focal adhesion pathway is extremely meaningful, among which JUN, FN1, and LAMB1 were verified to significantly differentially express in pterygium (P = 0.0011, P = 0.0018, and P = 0.0050, respectively). However, the all nine candidate SNPs (rs11688, rs3748814 in JUN; rs1263, rs1132741, rs1250259 in FN1; rs20556, rs35710474, rs25659, rs4320486 in LAMB1), were not statistically associated with pterygium.

CONCLUSION

Our results demonstrated that JUN, FN1, and LAMB1 polymorphisms were not associated with susceptibility to pterygium in Chinese Han population. Considering the fact that these three genes are differentially expressed in pterygium, further research is needed to explain its involvement in pterygium.

Regional features of the epidemiology of pterygium in the Republic of Bashkortostan

Background. Pterygium is ubiquitous and multifactorial; today, information on  the  prevalence of pterygium, risk factors, the relationship of its development with concomitant pathology and the type of life activity of patients in various regions of Russia is limited. All of the above led to the conduct of this epidemiological study in the Republic of Bashkortostan.

The aim of the study: to study the prevalence of pterygium, as well as to identify the relationship of risk factors for its development with the type of life activity and concomitant diseases in the urban and rural population of the Republic of Bashkortostan.

Methods. On the basis of the Ufa Research Institute of Eye Diseases, within the framework of the Ural Eye and Medical Study (UEMS) research project, a population study of people living in urban and rural regions of the Republic of Bashkortostan was carried out. The study involved 5899  people, including men – 43.7  % (2585  people), women – 56.3 % (3314 people), urban residents made 42.3 % (2491 people), rural – 57.7 % (3408 people).

Results. As a result of our study, pterygium was diagnosed in 138 people (204 eyes – 2.3 %) (95% CI: 2.0–2.7 %). One-way analysis showed a higher prevalence of pterygium associated (p˂0.10) with a number of systemic and ophthalmic parameters. However, according to the results of multivariate analysis, it was revealed that the prevalence of pterygium was significantly associated with older age (p = 0.006), rural area of residence (p = 0.001) and low educational level (p = 0.03).

Conclusion. The prevalence of pterygium in Republic of Bashkortostan according to the UEMS study was 2.3 %, or 23 people per 1000 population among people over 40 years old. The nature of the settlement influences the prevalence of pterygium in  the Republic of Bashkortostan. Pterygium was more common among older people among all respondents who took part in the study. In the study, pterygium was not a biomarker of general somatic diseases. 

UV Protection in the Cornea: Failure and Rescue

Simple Summary

The sun is a deadly laser, and its damaging rays harm exposed tissues such as our skin and eyes. The skin’s protection and repair mechanisms are well understood and utilized in therapeutic approaches while the eye lacks such complete understanding of its defenses and therefore often lacks therapeutic support in most cases. The aim here was to document the similarities and differences between the two tissues as well as understand where current research stands on ocular, particularly corneal, ultraviolet protection. The objective is to identify what mechanisms may be best suited for future investigation and valuable therapeutic approaches.

Abstract

Ultraviolet (UV) irradiation induces DNA lesions in all directly exposed tissues. In the human body, two tissues are chronically exposed to UV: the skin and the cornea. The most frequent UV-induced DNA lesions are cyclobutane pyrimidine dimers (CPDs) that can lead to apoptosis or induce tumorigenesis. Lacking the protective pigmentation of the skin, the transparent cornea is particularly dependent on nucleotide excision repair (NER) to remove UV-induced DNA lesions. The DNA damage response also triggers intracellular autophagy mechanisms to remove damaged material in the cornea; these mechanisms are poorly understood despite their noted involvement in UV-related diseases. Therapeutic solutions involving xenogenic DNA-repair enzymes such as T4 endonuclease V or photolyases exist and are widely distributed for dermatological use. The corneal field lacks a similar set of tools to address DNA-lesions in photovulnerable patients, such as those with genetic disorders or recently transplanted tissue.

Identification of Functional Genes in Pterygium Based on Bioinformatics Analysis

Purpose

The competing endogenous RNA (ceRNA) network regulatory has been investigated in the occurrence and development of many diseases. This research aimed at identifying the key RNAs of ceRNA network in pterygium and exploring the underlying molecular mechanism.

Methods

Differentially expressed long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and mRNAs were obtained from the Gene Expression Omnibus (GEO) database and analyzed with the R programming language. LncRNA and miRNA expressions were extracted and pooled by the GEO database and compared with those in published literature. The lncRNA-miRNA-mRNA network was constructed of selected lncRNAs, miRNAs, and mRNAs. Metascape was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses on mRNAs of the ceRNA network and to perform Protein-Protein Interaction (PPI) Network analysis on the String website to find candidate hub genes. The Comparative Toxicogenomic Database (CTD) was used to find hub genes closely related to pterygium. The differential expressions of hub genes were verified using the reverse transcription-real-time fluorescent quantitative PCR (RT-qPCR).

Result

There were 8 lncRNAs, 12 miRNAs, and 94 mRNAs filtered to construct the primary ceRNA network. A key lncRNA LIN00472 ranking the top 1 node degree was selected to reconstruct the LIN00472 network. The GO and KEGG pathway enrichment showed the mRNAs in ceRNA networks mainly involved in homophilic cell adhesion via plasma membrane adhesion molecules, developmental growth, regulation of neuron projection development, cell maturation, synapse assembly, central nervous system neuron differentiation, and PID FOXM1 PATHWAY. According to the Protein-Protein Interaction Network (PPI) analysis on mRNAs in LINC00472 network, 10 candidate hub genes were identified according to node degree ranking. Using the CTD database, we identified 8 hub genes closely related to pterygium; RT-qPCR verified 6 of them were highly expressed in pterygium.

Conclusion

Our research found LINC00472 might regulate 8 hub miRNAs (miR-29b-3p, miR-183-5p, miR-138-5p, miR-211-5p, miR-221-3p, miR-218-5p, miR-642a-5p, miR-5000-3p) and 6 hub genes (CDH2, MYC, CCNB1, RELN, ERBB4, RB1) in the ceRNA network through mainly PID FOXM1 PATHWAY and play an important role in the development of pterygium.

Pterygium excision with modified bare sclera technique combined with mitomycin C

PURPOSE

Numerous surgical methods, with varying rates of recurrence, have been applied for the treatment of pterygium. Adjuvant mitomycin C (MMC) application has shown promising results in the prevention of recurrence. Here we propose and describe modified bare sclera technique combined with the intraoperative application of MMC for pterygium excision.

STUDY DESIGN

Retrospective study.

METHODS

Primary pterygium patients who underwent pterygium excision via the bare sclera combined with 0.04% MMC technique from January 2014 to December 2016 were reviewed. In all patients, the subconjunctival pterygium strand was exposed and then sufficiently excised in combination with the safe use of MMC; i.e., the prevention of MMC dilution and diffusion to surrounding tissue. Surgical complications, recurrence rates, and recurrence onset were recorded.

RESULTS

This study involved 32 primary pterygium eyes (grade T1 = 22 eyes; 68.7%). The mean postoperative follow-up period was 26.4 ± 14.5 months (range: 12-60 months). MMC was applied for 1-3 min. The mean complete epithelialization was 12.6 ± 7.6 days and no surgical complications were observed. In 1 patient with double-head primary pterygium, recurrence occurred at 15-months postoperative.

CONCLUSIONS

The modified bare sclera technique combined with MMC application was found to be safe, effective, and presents good cosmetic appearance for the treatment of primary pterygium when safety points are strictly applied.

Prevalence of pterygium and its associated factors among adults aged 18 years and above in Gambella town, Southwest Ethiopia, May 2019

INTRODUCTION

A pterygium is a wing-shaped fibro-vascular growth of conjunctiva on the superficial cornea/conjunctiva. It is an elastotic degeneration of conjunctival stroma mainly due to Ultraviolet light exposure. The prevalence of pterygium varies in different environmental conditions. Its magnitude varies widely from 1.1% to 53% globally and in Ethiopia, it reaches from 8.8% to 38.7%.

OBJECTIVE

To determine the prevalence of pterygium and its associated factors among adults aged 18 years and above in Gambella town, Southwest Ethiopia, 2019.

METHODS AND MATERIALS

A community based cross-sectional study was conducted from April 15 to May 3, 2019, in Gambella town. A total of 402 study participants were selected using a systematic random sampling technique. A pre-tested semi-structured questionnaire, torch, and magnifying loops were used to collect data. The data was entered into epidemiological information 7.1 and exported to statistical package for social science version 20 for analysis. The binary and multivariate logistic regression analysis model was fitted to identify factors associated with pterygium. Odds ratio with respected 95% CI was used to identify the direction and strength of association.

RESULTS

A total of 400 participants were examined with a response rate of 99.50%. The mean age of the study participants was 39.9±9.8years. The prevalence of pterygium among adults aged 18 years and above in Gambella town was 127(31.80%), (95% CI: 27.3, 36.3). male sex (AOR = 2.10 (95% CI: 1.26, 3.45), sunlight exposure (AOR = 6.86 (95% CI: 4.00, 11.79) and outdoor works (AOR = 2.10 (95% CI: 1.21, 3.60) were positively associated with pterygium whereas wearing sunglass/hat was a protective factor.

CONCLUSION

The prevalence of pterygium was high among adults living in Gambella town. Wearing sunglass/hat and reducing exposure time to the sun was important to reduce the development of pterygium in adults.

Does systemic inflammation play a role in patients with pterygium?

PURPOSE

To compare parameters of systemic inflammation and serum lipid levels in patients with pterygium versus healthy individuals.

METHODS

Thirty-five patients with pterygium and 30 healthy individuals were enrolled as two respective groups in a retrospective study. The participants' complete blood count (CBC) parameters and levels of serum total cholesterol, low-density lipoprotein, high-density lipoprotein (HDL), and triglycerides (TG) were obtained from digital records and compared. Their neutrophil/lymphocyte, platelet/lymphocyte, and monocyte/HDL ratios were calculated and compared as well. As secondary outcomes, longitudinal length (LL), basal length (BL), and total area (TA) of pterygium among the patients were quantitatively measured by using ImageJ software. Correlations between serum parameters and pterygium measurements were analyzed.

RESULTS

Although between-group differences in CBC parameters and the ratios were not statistically significant, HDL levels were significantly lower (p = 0.014) and TG levels significantly higher (p = 0.031) among patients with pterygium than among the controls. A positive correlation was detected between the patient's age and the pterygium's BL (p = 0.002, r = 0.516), LL (p = 0.00, r = 0.547), and TA (p = 0.00, r = 0.515). Neutrophil levels negatively correlated with LL (p = 0.025, β = - 0.308) and TA (p = 0.002, β = - 0.420).

CONCLUSION

Local instead of systemic inflammation should be considered in the management of pterygium. Besides, decreased HDL levels may indicate systemic oxidative stress in patients with the condition.

Clinical demographics of pterygium excision and prevalence of conjunctival intraepithelial neoplasia: a 15-year review

PURPOSE

To find clinical demographics of pterygium surgery and prevalence of conjunctival intraepithelial neoplasia (CIN) in pterygium specimen.

METHODS

This is a retrospective, institutional study. The records of patients who had received pterygium excision from 2000 to 2014 were reviewed. Patients after complete ophthalmic "examinations", surgical procedures, and pathological reports were enrolled. Surgical procedures, pathology, external eye photography, prevalence of CIN in specimen, and demographic data were described.

RESULTS

Of 1787 pterygium cases, 928 were male and 859 were female. The mean age was 65.19 ± 14.21 years. Of these 1787 cases, 1435 (80.3%) cases had primary pterygium excision, while the others (n = 352; 19.7%) had pterygium excision for recurrence. Four cases presented CIN within pterygium tissue (0.22%). The mean age of pterygium patients with CIN was 57.75 ± 7.80 years. In stratified data, our patients who received primary and secondary pterygium excision were found prevalent in the eighth (28.2%) and seventh (26.1%) decade, respectively. Twelve percent of patients who underwent secondary pterygium excision had a recurrence and required another surgery. Patients requiring amniotic membrane transplantation (AMT) during primary pterygium excision were significantly younger (median, 58 years) than those (median, 67 years) without the assistance of AMT (p < 0.001). Similarly, AMT was utilized in younger patients (median, 56 years) during secondary pterygium excision, compared to those without AMT (median, 64 years) (p = 0.001).

CONCLUSION

CIN combined with pterygium is very rare. However, the possibility of the development of ocular surface squamous neoplasia in pterygium tissue should not be ignored. Meticulous pathological investigation of the surgical samples is important.

Prevalence and Associated Factors of Pterygium Among Adults Living in Kolla Diba Town, Northwest Ethiopia

Background

Pterygium is a disfiguring disease that can potentially lead to blindness. It is more common in warm, windy and dry climates of tropical and sub-tropical regions of Africa. Globally, the prevalence ranging from 0.07% to 53%. Studies conducted on the prevalence of pterygium in developing countries were limited with a wider discrepancy between them. In this study, we aimed to assess the prevalence of pterygium and its associated factors among adults in Kolla Diba town.

Methods

A community-based cross-sectional study was done in Kolla Diba town from May 30-June 16, 2019. A systematic random sampling technique was used to select 627 study participants. The basic ophthalmic examination was performed using portable slit lamp, 3x magnifying loop with torch light and a pretested structured questionnaire was completed. The data entered into EPI INFO version 7 and analyzed using SPSS version 20. Descriptive statistics and binary logistic regression analysis were employed. P-values of <0.05 were considered statistically significant.

Results

A total of 605 study participants were involved with a response rate of 96.5%. Among them, 317 (52.4%) participants were males. The mean age of the respondents was 38.18 ± 15.56 with a range of (18–95) in years. The overall prevalence of pterygium was 112 (18.5% (95% CI (15.6–21.7)). Being widowed (AOR = 7.32 (95% CI: 2.88, 18.57)), outdoor occupation (AOR = 2.50 (95% CI: 1.46, 4.29)), sun exposure (AOR = 2.38 (95% CI: 1.28, 4.43)), wind exposure (AOR = 1.97 (95% CI: 1.04, 3.72)), alcohol drinking (AOR = 2.26 (95% CI: 1.48, 4.63)), and severe blepharitis (AOR = 2.45 (95% CI: 1.48, 4.05)) had statistically significant positive association with pterygium.

Conclusion

The prevalence of pterygium was relatively higher. Being widowed, outdoor occupation, sun exposure, wind exposure, alcohol drinking, and severe blepharitis were significantly associated with the development of pterygium.

Clinical profile of pterygium in patients seeking eye care in India: electronic medical records-driven big data analytics report III

OBJECTIVE

To describe the clinical profile of pterygium in patients presenting to a multi-tier ophthalmology hospital network in India.

METHODS

This cross-sectional hospital-based study included 1,610,843 new patients presenting between 2010 and 2019. Patients with a clinical diagnosis of pterygium in at least one eye were included as cases. The data were collected using an electronic medical record system. Multiple logistic regression analysis with odds ratios (OR) was performed to identify the associated risk factors.

RESULTS

Overall, 168,807 (10.5%) new patients were diagnosed with pterygium, of which 43,692 (26%) patients complained about the lesion. The prevalence rates were 0.7% in children and 12.6% in adults. Majority of patients were female (54.5%) and had unilateral (57%) affliction. Among the 241,631 affected eyes, the pterygia were primary in 99.6%, nasally located in 94%, and were grade I-II in 84.8%. Four in 5 eyes did not have any cylindrical refractive error, and 44% had coexistent cataract. Pterygium surgery was indicated in 10.3% eyes. Female sex (OR 1.37), increasing age (OR 19.5), rural residence (OR 1.21), agriculture work (OR 2.19), manual labor (OR 2.05), low socioeconomic status (OR 2.14) and geographical location closer to the equator (OR 3.4) were identified as the risk factors for developing pterygium.

CONCLUSION

About one-tenth of individuals seeking eye care in India have pterygium in at least one eye. It rarely impacts vision, is commonly unilateral and nasal and usually does not require surgery. It is associated with increasing age, females, outdoor work, low income and geographical location closer to the equator.

Corneal Reinnervation and Sensitivity Recovery after Pterygium Excision

Purpose

To evaluate changes in corneal sensitivity and subbasal nerve density after pterygium excision.

Methods

This prospective trial included 22 eyes with nasal primary pterygium and 18 controls. Corneal sensitivity was evaluated using a Cochet–Bonnet esthesiometer in the nasal, superior, temporal, inferior, and center quadrants of the cornea before surgery and 10 days, 1 month, and 3months after surgery. The central cornea was analyzed using in vivo confocal microscopy (IVCM) before surgery and 1 and 3 months after surgery. Subbasal nerve density and other nerve parameters were analyzed using NeuronJ. Nerve tortuosity was evaluated and graded in individual IVCM scans. The tear film break-up time (TBUT) test and Schirmer's test were performed before surgery, as well as 1 and 3 months after surgery. All the same tests were performed in the controls.

Results

All affected eyes showed a significant increase in corneal sensitivity in the nasal corneal quadrant after surgery when compared with preoperative data (F = 37.3; P < 0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (P < 0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (P < 0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (P < 0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (F = 37.3; P < 0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (P < 0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (F = 37.3; P < 0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (

Conclusion

Pterygium patients demonstrated deteriorated corneal subbasal nerve fibers when compared with healthy controls in terms of nerve length, nerve trunks, and nerve branches. Therefore, pterygium excision improves corneal sensitivity and increases corneal subbasal nerve density.

Optical coherence tomography angiography for marginal corneal vascular remodelling after pterygium surgery with limbal-conjunctival autograft

PURPOSE

To demonstrate the marginal corneal vascular remodelling using optical coherence tomography angiography (OCTA) after pterygium surgery.

METHODS

Twenty-two eyes of 19 patients (8 males, 11 females; age, 58.68 ± 0.34 years) with primary grade-T3 nasal pterygium were enroled in this study. The eyes underwent excision of the pterygium followed by a free limbal-conjunctival autograft. OCTA was performed in the nasal limbal area before surgery and at 10 days, 1 month, and 3 months after surgery. The scans were analyzed in terms of postoperative vascular remodelling of the autograft and marginal corneal vascular arcades (MCAs).

RESULTS

Preoperatively, the pterygium presented as abnormal centripetal vascular growth in OCTA scans. The conjunctival vessel density in the nasal quadrant was 29.26% ± 1.00%, 15.80% ± 0.83%, 19.80% ± 0.88%, and 20.26% ± 0.89% before and 10 days, 1 month, and 3 months, respectively, after surgery (F = 1.55, P < 0.01). The vessel density of MCAs was 28.33% ± 0.88%, 42.09% ± 0.41%, and 42.46% ± 0.31% 10 days, 1 month, and 3 months, respectively, after surgery (F = 188.2, P < 0.01).

CONCLUSIONS

We describe a new application of OCTA for MCA vasculature imaging. Vascular remodelling of the graft and MCAs appeared at 1 month and continued for 3 months after surgery.

Effects of excimer laser phototherapeutic keratectomy in limbal-conjunctival autograft transplantation for recurrent pterygium: a retrospective case control study

BACKGROUND

Repeated surgery excisions could induce obvious irregular astigmatism in patients with recurrent pterygium. Our study is aimed to illustrate the effect of adjunct excimer laser phototherapeutic keratectomy (PTK) in limbal-conjunctival autograft transplantation on visual quality for patients with recurrent pterygium.

METHODS

Retrospective case-control study. Eyes that underwent pterygium excision with (PTK group) or without (control group) PTK from 2006 to 2017 were retrospectively included. Recurrence rate, preoperative and postoperative surface regularity index (SRI), surface asymmetry index (SAI), cylinder and LogMAR vision were collected. Postoperative anterior segment optical coherence topography and in vivo confocal microscopy were performed to monitor the cornea epithelium healing and cellular recovery process respectively.

RESULTS

A total of 99 eyes of 99 patients were collected, of which 39 were treated with PTK and 60 without PTK. The mean follow-up time was 50.4 ± 38.1 months. The recurrence rate was 10.3% (4 eyes) in the PTK group and 13.3% (8 eyes) in the control group (p = 0.759). The SRI decreased 0.53 (range: - 0.88, 2.81), SAI decreased 0.53 (range: - 0.64, 2.94), and the cylinder decreased 2.08 (range:-0.16, 9.40) D in the PTK group, and the corresponding values were 0.48 (range:-0.45, 2.27), 0.27 (range:-1.06, 2.21) and 0.71 (range:-1.75, 3.55) D in the control group, respectively (Z = 1.76, 2.15, and 3.97, p = 0.005, 0.016, and 0.000 respectively). LogMAR vision improved in both groups after surgery, with an improvement of 0.18 (range: 0.00, 0.70) in the PTK group and 0.06 (range: - 0.12, 0.50) in the control group (Z = 4.08, p = 0.000). Besides, the eyes treated with PTK showed faster re-epithelization and better cellular recovery.

CONCLUSIONS

For recurrent pterygium, surgical excision with adjunct PTK might be a better option with improved corneal surface and vision outcomes.

Identification and Interaction Analysis of Significant Genes and MicroRNAs in Pterygium

PURPOSE

MiRNAs have been widely analyzed in the occurrence and development of many diseases, including pterygium. This study aimed to identify the key genes and miRNAs in pterygium and to explore the underlying molecular mechanisms.

METHODS

MiRNA expression was initially extracted and pooled by published literature. Microarray data about differentially expressed genes was downloaded from Gene Expression Omnibus (GEO) database and analyzed with the R programming language. Functional and pathway enrichment analyses were performed using the database for Annotation, Visualization and Integrated Discovery (DAVID). The protein-protein interaction network was constructed with the STRING database. The associations between chemicals, differentially expressed miRNAs, and differentially expressed genes were predicted using the online resource. All the networks were constructed using Cytoscape.

RESULTS

We found that 35 miRNAs and 301 genes were significantly differentially expressed. Functional enrichment analysis showed that upregulated genes were significantly enriched in extracellular matrix (ECM) organization, while downregulated genes were mainly involved in cell death and apoptotic process. Finally, we concluded the chemical-gene affected network, miRNA-mRNA interacted networks, and significant pathway network.

CONCLUSION

We identified lists of differentially expressed miRNAs and genes and their possible interaction in pterygium. The networks indicated that ECM breakdown and EMT might be two major pathophysiological mechanisms and showed the potential significance of PI3K-Akt signalling pathway. MiR-29b-3p and collagen family (COL4A1 and COL3A1) might be new treatment target in pterygium.

Prevalence and risk factors for pterygium: a cross-sectional study in Han and Manchu ethnic populations in Hebei, China

AIMS

To investigate the prevalence, ethnic differences and associated risk factors for pterygium in Han and Manchu populations aged 40-79 years in Hebei province, China.

DESIGN

Cross-sectional study, as a part of the China National Health Survey.

SETTING

Hebei province, China.

PARTICIPANTS

A multistage cluster sampling method with urbanisation level-based stratification was used to select participants for this study. A total of 4591 individuals over 40 years were recruited for this study. Inclusive criteria: (1) residents who had been living in Hebei for more than 1 year; (2) Han individuals with both parents being Han, or Manchu individuals with both parents being Manchu; (3) underwent ophthalmic examinations and (4) information in the questionnaire was complete.

MAIN OUTCOME MEASURES

Multiple logistic regression analysis was used to evaluate the association between pterygium prevalence and factors of interest.

RESULTS

A total of 3790 individuals (2351 Hans and 1439 Manchus) met the study criteria, of which 248 were diagnosed with pterygium (6.5%). There was no significant difference between the prevalence rates in Hans (6.2%) and Manchus (7.2%) (p=0.232). Multivariate analysis revealed that the risk factors for grade 2 or higher pterygium were increasing age (p<0.001) and rural residence (OR 1.83; 95% CI 1.11 to 3.02; p=0.018), while the protective factors include gender (female) (OR 0.58; 95% CI 0.37 to 0.88; p=0.011), cigarette smoking (OR 0.53; 95% CI 0.34 to 0.83; p=0.005) and myopia (OR 0.50; 95% CI 0.33 to 0.77; p=0.002). Premature menopause (OR 2.66; 95% CI 1.05 to 6.72; p=0.038) increased the risk of grade 2 or higher pterygium in females, while higher high-density lipoprotein (HDL) (OR 1.94; 95% CI 1.08 to 3.47; p=0.027) was a risk factor of grade 2 or higher pterygium in males.

CONCLUSION

The overall prevalence of pterygium in Han and Manchu population in Hebei, China was approximately 6.1%. There were no differences in the prevalence of pterygium between Hans and Manchus, and the race was not a risk factor. This is the first study to report on the positive association between premature menopause and pterygium in females and between higher HDL levels and pterygium in males.

Evaluation of antimitotic and antiangiogenic effect of preoperative subconjunctival application of mitomycin C in primary pterygium: a randomized trial

PURPOSE

To evaluate the influence of preoperative mitomycin C (MMC) on the proliferative behavior of fibroblasts and fibrovascular tissue derived from the primary pterygium using the immunohistochemical method (Ki67 and CD34).

DESIGN

Randomized clinical trial.

SUBJECTS, PARTICIPANTS AND/OR CONTROLS

Sixty-five patients with primary pterygium were randomly selected and divided into one of three groups. The control group had 29 patients that were only submitted to pterygium removal. The group that received the MMC injection a month before surgery had 16 patients, and the group that received the MMC 2 weeks before surgery had 20 patients. Each patient only had one eye operated on.

METHODS

Sixty-five patients were selected to undergo pterygium excision surgery. We randomly placed the patients into three groups: one without MMC (n = 29), one with MMC application 1 month before surgery (n = 16) and another with MMC application 2 weeks before surgery (n = 20). Subconjunctival injection was applied with 0.1 ml of 0.02% MMC in the pterygium body, and patients were followed for 2 years.

MAIN OUTCOME MEASURES

Proliferative behavior of fibroblasts and fibrovascular tissue using the immunohistochemical method (Ki67 and CD34) comparing the three groups.

RESULTS

Of the total 29 patients (44.6%) in the control group (without MMC application), 11 cases had recurrence (37.9%), of which seven (63.6%) were within 3 months of follow-up and four (36.3%) within 6 months of follow-up. The mean proliferation index of the recurrent cases was 4.5%, and of the cases without recurrence, it was 6.1%. There were 16 patients (24.6%) in the MMC application group 1 month before surgery, in which one case (6.25%) recurred at 6 months. In the group with MMC application 2 weeks before surgery, of the total of 20 patients (30.7%), there was one case of recurrence (5%) at 6 months. The proliferation index of the group that had MMC administered and did not have a recurrence was 7.2%, and in the group with recurrence, it was 6.4%. The CD34-labeled cell count was 5.8% among cases with recurrence and 5.6% in cases without recurrence. No side effects of MMC application were reported during the study follow-up period.

CONCLUSION

MMC was efficient to reduce the recurrence index despite the absence of a direct relation with its antimitotic and antiangiogenic effect in the samples that were analyzed.

National and subnational prevalence and burden of glaucoma in China: A systematic analysis

Background

Glaucoma, the second leading cause of blindness, affects approximately 64.3 million individuals worldwide. In China, demographic ageing is in rapid progress. Yet detailed and up-to-date estimates of the scale of glaucoma are rare. We aimed to quantify and understand the prevalence and burden of glaucoma in China from 1990 to 2015, with projections until 2050.

Methods

For this systematic review and meta-analysis, we searched China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Biomedicine Literature Database (CBM-SinoMed), PubMed, Embase and Medline using comprehensive search strategies to identify all relevant articles that have reported the prevalence of glaucoma in the general Chinese population. We used a multilevel mixed-effect meta-regression to estimate the prevalence rates of primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG), and a random-effects meta-analysis to pool the overall prevalence of secondary glaucoma. United Nations population data were used to estimate and project the number of people with glaucoma from 1990 to 2050. Univariable and multivariable meta-regressions were conducted to assess the association between the prevalence of POAG and PACG and relevant demographic and geographic factors. The national burden of POAG and PACG in the years 2000 and 2010 were distributed to six geographic regions accordingly.

Results

From 1990 to 2015, the prevalence of all glaucoma ranged from 2.59% (95% CI = 1.96-3.49) to 2.58% (95% CI = 1.94-3.47). For different subtypes of glaucoma, the overall prevalence of POAG ranged from 1.03% (95% CI = 0.67-1.58) in 1990 to 1.02% (95% CI = 0.67-1.57) in 2015, PACG from 1.41% (95% CI = 1.18-1.68) to 1.40% (95% CI = 1.17-1.68). The overall prevalence of secondary glaucoma was 0.15% (95% CI = 0.10-0.23) during this period. The number of people with all glaucoma in China was 5.92 million (95% CI = 4.47-7.97) in 1990, and 13.12 million (95% CI = 9.88-17.68) in 2015. This increasing trend was also witnessed in different subtypes of glaucoma. The number of people affected by POAG increased from 2.35 million (95% CI = 1.54-3.60) in 1990 to 5.22 million (95% CI = 3.40-7.98) in 2015, PACG from 3.22 million (95% CI = 2.70-3.84) to 7.14 million (95% CI = 5.97-8.53), and secondary glaucoma from 0.34 million (95% CI = 0.23-0.53) to 0.76 million (95% CI = 0.51-1.17). In 2015, more than half (54.42%) of the glaucoma cases were PACG, followed by POAG (39.79%) and secondary glaucoma (5.79%). By 2050, the number of all glaucoma cases in China will be 25.16 million (95% CI = 18.96-33.86). In the multivariable meta-regressions, the odds ratio (OR) for each decade's increase in age was 1.43 (95% CI = 1.33-1.55) for POAG, and 1.65 (95% CI = 1.51-1.80) for PACG; males were more likely to have POAG (OR 1.36, 95% CI = 1.17-1.59), but less likely to have PACG (OR 0.53, 95% CI = 0.46-0.60) compared with females. After adjustment of age and gender, people living in urban areas were more likely to have POAG compared with those in rural areas (OR 1.54, 95% CI = 1.02-2.35). People in Northeast China were at a higher risk (OR 1.77, 95% CI = 1.07-2.94) of having PACG than people in East China. Among the six regions, East China owed the most POAG and PACG cases, whereas Northwest China owed the least.

Conclusions

This systematic review and meta-analysis suggests a substantial burden of glaucoma in China, with great variances among the different age groups, genders, settings and geographic regions. With the dramatic ageing trend in the next three decades, the prevalence and burden of glaucoma will continue to increase. More elaborate epidemiological studies are needed to optimise public health strategies for mitigating this important health problem.