The prevalence and risk factors for pterygium in an adult Chinese population in Singapore: the Tanjong Pagar survey

Are Periocular and Systemic Allergy Conditions Risk Factors for Pterygium?

PURPOSE

To evaluate risk factors for pterygium and prevalence of periocular and systemic diseases among patients with pterygium.

METHODS

A retrospective case-control study was conducted among members of Clalit Health Services (CHS) in Israel, from 2001 to 2022. A total of 13,944 patients diagnosed with pterygium were included. For each case, three controls were matched among all CHS patients according to year of birth, sex, and ethnicity. Mixed models were used to assess differences in demographic characteristics, ocular and systemic diseases between the groups. Generalized estimating equation (GEE) logistic regression was used to estimate the odds ratios (OR) and adjust for confounders.

RESULTS

The average age of pterygium patients was 49 ± 17 years; 51% were male. The results showed significant associations between pterygium and risk factors of vernal kerato-conjunctivitis (OR 2.52, 95% confidence interval [CI]: [1.96-3.24]), chronic allergic conjunctivitis (OR 1.98, 95% CI: [1.65-2.39]), blepharitis (OR 1.91, 95% CI: [1.78-2.04]), chalazion (OR 1.47, 95% CI: [1.30-1.67]) and unspecified systemic allergy (OR 1.21, 95% CI [1.09-1.34]), after adjusting for rural residency status. Glaucoma (OR 0.74, 95% CI [0.64-0.85]) and smoking (OR 0.70, 95% CI [0.66-0.75]) were protective factors against pterygium.

CONCLUSION

Systemic and periocular inflammatory and allergic diseases are risk factors for pterygium.

Human papilloma virus presence and its physical status in primary pterygium

Pterygium is one of the most frequent pathologies in ophthalmology, and is a benign, overgrowth of fibrovascular tissue, often with a wing-like appearance, from the conjunctiva over the cornea. It is composed of an epithelium and highly vascular, sub-epithelial, loose connective tissue. There is much debate surround the pathogenesis of pterygium and a number of theories have been put forward including genetic instability, cellular proliferation, inflammatory influence, and degeneration of connective tissue, angiogenesis, aberrant apoptosis and viral infection. At present, the involvement of human papillomavirus (HPV) in the genesis of pterygium is controversial, as have reported that HPV is present in 58% of cases, while others have failed to detect HPV in pterygium. In this study, we evaluated the presence and viral genotype of HPV DNA in pterygia and healthy conjunctiva sample, and virus integration into the cellular genome. Forty primary pterygia samples and 12 healthy conjunctiva samples were analyzed to HPV DNA presence by polymerase chain reaction, using MY09/MY11 primers of HPV-L1 gene. Viral genotype was identified by DNA sequence analysis of this amplicon. HPV integration into the cellular genome was analyzed by western blot detecting HPV-L1 capsid protein. Presence of HPV was observed in 19 of the 40 pterygia samples. In contrast, healthy conjunctiva samples were negative. To determine virus type, sequence analyses were performed. Interestingly, 11 out of the 19-pterygium samples were identified as HPV-11 type, meanwhile, the remaining 8 pterygium samples were identified as HPV-18. HPV-L1 capsid protein were found only in 3 out of the 10 samples studied. In conclusion, our study identified the presence of HPV DNA exclusively in pterygium samples and described HPV-11 and -18 genotypes. Our results suggest that HPV may be involved in the pathogenesis of pterygium. On the other hand, the expression of the L1-HPV protein suggests viral integration into the cellular genome.

Prevalence and associated factors for pterygium in a Chinese rural population with type 2 diabetes in a cross-sectional study: Jiangsu Diabetic Eye Disease Study (JDEDS)

PURPOSE

To investigate the pterygium prevalence and evaluate risk factors of pterygium in rural type 2 diabetic (D2M) patients aged 50 years and above in Funing Country, Jiangsu Province, China.

METHODS

A cross-sectional ophthalmic survey was conducted in type 2 diabetes mellitus (D2M) patients aged ≥ 50 years in Funing County, Jiangsu Province, China, which was named Jiangsu Diabetic Eye Disease Study (JDEDS). All participants underwent a comprehensive questionnaire and ocular examination. Pterygium was diagnosed by slit lamp examination. The risk factors associated with pterygium were evaluated with logistic regression models.

RESULTS

The prevalence of pterygium was 22.37% (n = 427) and 95% confidence interval (CI) (20.50-24.24%) in D2M patients aged 50 years and above in JDEDS. The prevalence of pterygium was 18.32% (95% CI 15.33-21.32%) in men and 24.43% (95% CI 22.06-26.80%) in women. Women had a higher prevalence than men (p = 0.001). Multivariate analysis showed, for male participants with D2M, pterygium was independently associated with increasing age [70-79 years: OR and 95% CI 2.49(1.20-5.18), p = 0.014; ≥ 80 years: 4.84(2.04-11.47), p < 0.001], while cigarette smoking was the protective factors, especially in current smoker [OR and 95% CI 0.79(0.67-0.92); p = 0.003]. For female participants with D2M, age [60-69 years OR and 95% CI 1.68(1.07-2.62), p = 0.023; 70-79 years: 2.62(1.69-4.06), p < 0.001; ≥ 80 years:3.24(1.70-5.90), p < 0.001], hypertension [OR and 95% CI 1.40(1.05-1.87), p = 0.024], BMI 24-27.9 [OR and 95% CI 1.20(1.00-1.44), p = 0.047], higher HbA1c [(5.6-7.9) % OR and 95% CI 1.42(1.10-1.82), p = 0.006; (8.0-9.9) %: 1.32(1.10-1.58), p = 0.003] were risk factors.

CONCLUSIONS

D2M patients aged over 50 years has a high prevalence of pterygium in JDEDS. The pterygium prevalence is higher in female D2M participants. Diabetes and related factors may be risk factors of pterygium in female D2M patients. Further studies are needed to explore the gender difference in the pathogenesis of pterygium in D2M subjects.

Ocular surface squamous neoplasia in a patient following oral steroids for contralateral necrotising scleritis

A male patient in his 70s presented with left eye necrotising scleritis. His ocular history was significant for pterygium excision with mitomycin C 3 months prior in the affected eye, open-angle glaucoma, nuclear sclerosis cataract and previous sixth cranial nerve palsy. Scleral culture was negative and blood work was positive for rheumatoid factor and HLA-B27. The patient was treated for necrotising scleritis with oral doxycycline, vitamin C, ranitidine and prednisone with gradual taper over 45 days. Two months after initiating treatment, his necrotising scleritis achieved complete resolution; however, a new-onset ocular surface squamous neoplasia (OSSN) was identified at the temporal limbus of the contralateral eye. He was treated with topical interferon alpha-2b 1 million IU qid and achieved complete resolution after 4 months. The case highlights both the acute precipitation of OSSN following oral steroids and a sight-threatening complication following pterygium excision.

The association of sun exposure, ultraviolet radiation effects and other risk factors for pterygium (the SURE RISK for pterygium study) in geographically diverse adult (≥40 years) rural populations of India -3rd report of the ICMR-EYE SEE study group

Purpose

To determine the prevalence and risk factors for pterygium in geographically diverse regions of India.

Methods

A population-based, cross-sectional multicentric study was conducted in adults aged ≥40 years in plains, hilly and coastal regions of India. All participants underwent a detailed questionnaire-based assessment for sun exposure, usage of sun protective measures, exposure to indoor smoke, and smoking. Detailed ocular and systemic examinations were performed. Pterygium was diagnosed and graded clinically by slit-lamp examination. Association of pterygium with sociodemographic, ophthalmological, and systemic parameters was assessed. Physical environmental parameters for the study period were estimated.

Results

Of the 12,021 eligible subjects, 9735 (81% response rate) participated in the study. The prevalence of pterygium in any eye was 13.2% (95% CI: 12.5%-13.9%), and bilateral pterygium was 6.7% (95% CI: 6.2–7.2). The prevalence increased with age (<0.001) irrespective of sex and was highest in those aged 60–69 years (15.8%). The prevalence was highest in coastal (20.3%), followed by plains (11.2%) and hilly regions (9.1%). On multi-logistic regression, pterygium was positively associated with coastal location (P<0.001), illiteracy (P = 0.037), increasing lifetime sun exposure (P<0.001), and negatively associated with BMI ≥25 kg/m2 (P = 0.009).

Conclusion

Pterygium prevalence is high in the rural Indian population. The association of pterygium with several potentially modifiable risk factors reflects its multifactorial etiology and provides targets for preventive measures.

High HDL-C and high LDL-C are risk factors of pterygium in a population-based cross-sectional study in Southern China: the Dongguan Eye Study

OBJECTIVES

To investigate the relationship between serum lipids and pterygium in a large-scale rural population aged 40 years or older from Southern China.

STUDY DESIGN

The Dongguan Eye Study was a cross-sectional population-based study from September 2011 to February 2012.

SETTING

The area was set in the rural area of Dongguan, Southern China.

PARTICIPANTS

Adult rural population aged 40 or older.

METHODS

Participants underwent physical, haematological and ophthalmic examinations.

PRIMARY AND SECONDARY OUTCOME MEASURES

The frequency and risk factors of pterygium.

RESULTS

A total of 11 357 participants were eligible for inclusion and 8952 (78.8%) participants were enrolled for the systemic and ophthalmic examinations. The prevalence of pterygium was 17.3% after adjusting the sex and age distribution, 22.0% in participants with hypercholesterolaemia (total cholesterol ≥6.22 mmol/L (240 mg/dL)) and 21.8% in those with low-density lipoprotein-cholesterol (LDL-C) ≥4.14 mmol/L (160 mg/dL), respectively. After adjusting for multiple confounding factors, higher level of high-density lipoprotein-cholesterol (HDL-C) (OR: 1.23, 95% CI: 1.06 to 1.41) and LDL-C (OR: 1.13, 95% CI: 1.06 to 1.20) were positively associated with the risk of pterygium. The ORs for HDL-C or LDL-C with pterygium were significantly greater in participants aged 40-49 years than those aged 50 years or above (P for interaction <0.001). Furthermore, increased HDL-C showed greater association with pterygium in normal body mass index (BMI) group compared with overweight group (P for interaction=0.002).

CONCLUSION

Increased HDL-C and LDL-C are risk factors of pterygium, especially in people <50 years or those with normal BMI level. Strict control of HDL-C and LDL-C may be a new prevention method in reducing the risk of pterygium.

Pseudomonas aeruginosa Scleritis following Pterygium Surgery with Mitomycin C or Beta Irradiation: Three-Case Report

Purpose

To report three cases of culture-positive Pseudomonas aeruginosa scleritis following pterygium surgery. Patients and Methods. A retrospective study of all patients of Pseudomonas aeruginosa scleritis after pterygium surgery presented from May 2017 to May 2020 was performed. Patient demographics and clinical characteristics included age, gender, time between prior surgery and onset, adjunctive therapy, risk factors, initial visual acuity, final visual acuity, clinical features, medical treatment, and surgical intervention were analyzed.

Results

Three eyes of three patients with clinical characteristics and laboratory-confirmed Pseudomonas aeruginosa scleritis were identified. Two patients were related with mitomycin C application after pterygium surgery, and only one had beta irradiation. Antibiotic administration and scleral debridement were required in 3 patients. One eye was enucleated. Final visual outcomes of two patients were improved.

Conclusions

Pseudomonas aeruginosa scleritis after pterygium surgery is a crucial ophthalmic disease. An early diagnosis with a prompt intensive antibiotic treatment in combination with surgical interventions may improve visual outcome.

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. 

Sunlight exposure and eye disorders in an economically active population: data from the KNHANES 2008-2012

BACKGROUND

Sunlight exposure is a major risk factor for eye disorders. Most outdoor workers cannot avoid sunlight exposure. This study aimed to analyze the relationship between outdoor sunlight exposure and eye disorders in an economically active population.

METHODS

This study analyzed the 2008-2012 Korea National Health and Nutritional Examination Survey data. Sunlight exposure was categorized as < 5 hours and > 5 hours. We also analyzed the dose-dependent relationship between exposure to sunlight and eye disorders (cataracts, pterygium, and age-related macular degeneration [AMD]) using data from 2010 to 2012 by subdividing the exposure groups into < 2 hours, 2-5 hours, and ≥ 5 hours. Eye disorders were diagnosed by an ophthalmologist. The study participants were stratified by sex, and the results were analyzed using the χ2 test and multiple logistic regression analysis.

RESULTS

In the female group, the odds ratio of pterygium in the high-level sunlight exposure group was 1.47 (95% confidence interval [CI]: 1.15-1.89). Regarding AMD, the odds ratios were 1.42 (95% CI: 1.16-1.73), 1.33 (95% CI: 1.03-1.73), and 1.58 (95% CI: 1.15-2.16) in the total, male, and female groups, respectively. Analysis of the dose-response relationship revealed that the odds ratios of pterygium in the high-level sunlight exposure subgroups of the total and female groups were 1.62 (95% CI: 1.25-2.08) and 2.00 (95% CI: 1.39-2.88), respectively.

CONCLUSIONS

This study demonstrated a relationship between sunlight exposure and eye disorders in an economically active population. Women were found to be especially vulnerable to pterygium. However, additional prospective studies to clarify the pathophysiology of pterygium are needed.

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.

Fifteen-year incidence rate and risk factors of pterygium in the Southern Indian state of Andhra Pradesh

PURPOSE

To report 15-year incidence rate and associated risk factors of pterygium among people aged 30 years and above at baseline in the rural clusters of longitudinal Andhra Pradesh Eye Disease Study (APEDS III).

METHODS

The baseline APEDS I included 7771 participants of which 6447 (83%) were traced and 5395 (83.7%) were re-examined in APEDS III. To estimate the incidence of pterygium, we selected participants who were 30 years and above at baseline (4188), of which 2976 were traced and 2627 (88.3%) were examined, and based on inclusion criteria, 2290 participants were included in the study. The incidence rate of pterygium was defined as the proportion of people free of pterygium at baseline who had developed the condition at 15-year follow-up (range 13-17 years). Univariate and multivariable analyses for risk factors were undertaken.

RESULTS

The sex-adjusted incidence rate of pterygium was 25.2 per 100 person-years (95% CI 24.8 to 25.7) which was significantly higher for men than women (26.3 per 100 person-years (95% CI 25.6 to 27.0) and 24.7 (95% CI 24.1 to 25.3) respectively). At the multivariable analysis, male gender (RR: 1.35, 95% CI 1.0 to 1.83), no formal education (RR: 2.46, 95% CI 1.22 to 4.93), outdoor occupation (RR: 1.47, 95% CI 1.14 to 1.9) and lower body mass index (BMI) (<18.5) (RR: 1.25, 95% CI 1.02 to 1.55) were associated with increased risk of pterygium.

CONCLUSIONS

The overall incidence rate of pterygium was high in this rural population, especially in men and those engaged in outdoor activities, lack of formal education and with lower BMI. It is likely that greater exposure to ultraviolet light is a major contributing factor, thus warranting preventive strategies.

Influences of the three-dimensional parameters of pterygium on corneal astigmatism and the intraocular lens power calculation

Pterygium morphology had great effect on corneal astigmatism and intraocular lens (IOL) power calculation in cataract patients. However, previous studies all focused on the pterygium surface parameters, the invasion degree or cross-sectional area of the pterygia into the corneal stroma were neglected. We studied the effect of three-dimensional parameters of pterygium on corneal astigmatism and IOL power prediction. We enrolled 81 eyes of 81 patients with primary nasal pterygium, measured the corneal astigmatism (Pentacam HR) and predicted IOL power change (IOLmaster500) before and after pterygium surgery. The three-dimensional parameters of pterygium (length, width, area, height and invasion cross-sectional area) were measured by slit lamp photography and Scheimpflug images. After pterygium surgery, corneal astigmatism decreased from 4.35 ± 4.24 to 1.07 ± 0.95 D and total corneal refractive power increased from 43.02 ± 1.96 to 43.95 ± 0.95 D (both P < 0.001). The predicted IOL power decreased from 22.87 ± 2.82 to 21.71 ± 2.85 D (P < 0.001) after surgery. Notably, 34 eyes (41.98%) had ≥3.0 D of pterygium induced astigmatism (PIA), and 33 eyes (40.74%) had ≥1.0 D of predicted IOL power change. PIA was independently influenced by the pterygium surface area (r = 0.43, P < 0.001) and cross-sectional area (r = 1.25, P = 0.018), while the predicted IOL power change was independently affected by the pterygium width (r = 0.70, P < 0.001). Cataract surgeons could evaluate the effects of a pterygium according to its three-dimensional parameters and prepare an optimal surgical strategy for cataract combined pterygium patients.

Design and baseline data of a population-based metabonomics study of eye diseases in eastern China: the Yueqing Ocular Diseases Investigation

Background

China is undergoing a massive transition toward an urban and industrial economy. These changes will restructure the demographics and economy which will eventually influence the future patterns of disease. The risk factors of vision-impairing eye diseases remain ambiguous and poorly understood. Metabolomics is an ideal tool to understand and shed light on the ocular disease mechanisms for earlier treatment. This article aims to describe the design, methodology and baseline data of the Yueqing Ocular Diseases Investigation (YODI), a developed county population-based study to determine the prevalence and primary causes of visual impairment; also with metabonomics analysis we aimed to identify, predict and suggest some preventive biomarkers that cause blindness.

Methods

A population-based, cross-sectional study. Randomized clustering sampling was used to identify adults aged 50 years and older in Xiangyang Town, Yueqing county-level City. The interviews covered demographic, behavioral, ocular risk factors and mental health state. The ocular examination included visual acuity, autorefraction, intraocular pressure, anterior and posterior segment examinations, fundus photography, retinal tomography and angiography, and visual field testing. Anthropometric measurements included height and weight, waist and hip circumference, blood pressure, pulse rate, electrocardiogram, and abdominal ultrasound scan. A venous blood sample was collected for laboratory tests and metabonomics studies.

Results

Of the 5319 individuals recruited for the YODI, 4769 (89.7%) subjects were enrolled for analyses. The median age was 62.0 years, and 45.6% were male. The educational level of illiteracy or semi-illiteracy, primary, middle and high school or above was 29.8%, 45.5%, 20.1%, and 3.3%, respectively. Majority of the participants were female, younger, and less educated when compared with nonparticipants. The average body mass index and waist-hip ratios were 24.4 ± 3.4 kg/m² and 0.9 ± 0.1 respectively. Blood sample collection reached a sample size of 1909 (479 from subjects with self-reported diabetes and 1430 from one-third of the 4290 subjects without self-reported diabetes).

Conclusions

The YODI provides population-based data with a high response rate (89.7%) on the prevalence and primary causes of major vision-impairing eye diseases in developed county areas in eastern China. Metabonomics analysis from YODI will provide further association of metabolic characteristics with the visual impairment eye diseases. The risk prediction model could be created and has the potential to be generalized to developed eastern areas in China for prevention.

Pterygium in adults from the Brazilian Amazon Region: prevalence, visual status and refractive errors

AIMS

To determine prevalence of pterygium, its role as main cause of unilateral and bilateral visual impairment and blindness and its impact on refractive errors from adults living in a high ultraviolet exposure area in the Brazilian Amazon Region.

METHODS

Cluster sampling was used in randomly selecting subjects ≥45 years of age from urban and rural areas of Parintins city. Eligible subjects were enumerated through a door-to-door household survey and invited for an eye exam including refraction. Pterygium was assessed considering location (nasal, temporal or both) and size (<3 mm or ≥3 mm reaching or not pupillary margin).

RESULTS

A total of 2384 persons were enumerated and 2041 (85.6%) were examined. Prevalence of pterygium was 58.8% (95% CI 53.8% to 63.7%) and associated with male gender (OR=1.63; 95% CI 1.37 to 1.94; p=0.001), while higher education was a protective factor (OR=0.63; 95% CI 0.44 to 0.92; p=0.018). Older age and rural residence were associated with pterygium ≥3 mm reaching or not pupillary margin, while higher education was a protective factor for pterygium ≥3 mm reaching pupillary margin. Prevalence of pterygium as cause of visual impairment and blindness was 14.3% and 3.9%, respectively. Significantly higher hyperopic refractive errors were found in eyes with pterygium ≥3 mm reaching or not pupillary margin.

CONCLUSIONS

Pterygium was highly prevalent and the second cause of visual impairment and blindness after provision of refractive correction. Risk factors for pterygium were male gender, advanced age, lower education and rural residency. Strategies to provide pterygium early detection and proper management should be considered by healthcare authorities in this population.

Pterygium Prevalence and Its Associations in a Russian Population: The Ural Eye and Medical Study

PURPOSE

To assess the prevalence of pterygia and its associations in a population in Russia.

DESIGN

Population-based cross-sectional study.

METHODS

The Ural Eye and Medical Study was performed in a rural and urban area in Ufa/Bashkortostan 1300 km east of Moscow. Out of 7328 eligible individuals aged 40+ years, 5899 (80.5%) individuals participated and underwent an ocular and systemic examination. Pterygia, defined as conjunctival extensions onto the clear cornea, were diagnosed upon slit-lamp examination and on corneal photographs.

RESULTS

Mean pterygium prevalence (per individual) was 138/5888 (2.3%; 95% confidence intervals [CI]:2.0, 2.7), with bilateral occurrence in 45 individuals (32.6% of patients with pterygium; 0.8% of study population). Pterygium prevalence increased from 0.8% (95% CI: 0.02, 1.6) in the age group from 40 to <45 years to 3.6% (95% CI: 2.1, 5.1) in the age group of 75+ years. In multivariable analysis, higher pterygium prevalence was associated with older age (P = .006; odds ratio [OR]: 1.03; 95% CI: 1.01, 1.04), rural vs urban region of habitation (P < .001; OR: 2.33; 95% CI: 1.57, 3.46), and lower level of education (P = .03; OR: 0.89; 95% CI: 0.81, 0.99), while the pterygium prevalence was statistically independent of sex (P = .34), Russian vs non-Russian ethnicity (P = .59), presence of diabetes mellitus (P = 1.00), arterial hypertension (P = .86), vegetarian vs mixed diet (P = 1.00), blood lipid concentration (P > .30), history of cardiovascular disease (P = .49), or axial length (P = .52).

CONCLUSIONS

In this rural and urban, typically multiethnic Russian study population aged 40+ years, a higher pterygium prevalence (mean: 2.3%) was correlated with older age, rural region of habitation, and lower educational level, while it was statistically independent of most other systemic or ocular parameters. A pterygium was not a biomarker for an internal medical disease.

Shared gene signature between pterygium and meibomian gland dysfunction uncovered through gene-expression meta-analysis

BACKGROUND

Pterygium and meibomian gland dysfunction (MGD) are two clinically correlated ocular diseases. We propose to investigate the shared gene signature between pterygium and MGD.

METHODS

Microarray datasets were retrieved from the Gene Expression Omnibus (GEO) database. Initial processing of the data was performed using the R programming package. Gene-expression values were log2 transformed and normalized by quantile normalization. The differentially expressed genes (DEGs) in each individual dataset were analyzed by the limma package. The integration of different pterygium datasets and gene-expression meta-analysis was conducted by the NetworkAnalyst package. A Venn diagram was created to find the overlapped DEGs between MGD and pterygium datasets. Gene ontology enrichment and pathway analysis were performed using the ToppGene Suite.

RESULTS

We found 193 DEGs significantly up-regulated in pterygium, with the combined effect sizes ranging from 1.53 to 3.78. A gene signature consisting of 11 DEGs were found to be shared by pterygium and MGD (SPRR3, SERPINB13, NMU, KRT10, IL37, KRT6B, PI3, S100A2, MAL, AURKA, and RGCC), and bioinformatics analyses showed that these overlapped DEGs were significantly enriched in pathways related to keratinization, cell-cycle regulation, and formation of the cornified envelope.

CONCLUSION

We identified a shared gene signature between pterygium and MGD through gene-expression meta-analysis. The analysis of this signature underlined that keratinization-related pathways may play important roles in the development of these two clinically correlated pathologies.

Prevalence, pattern and factors associated with ocular disorders in small-scale welders in Katwe, Kampala

Background

Welders are at an increased risk of eye disorders as a result of their occupation, leading to enormous vocational and economic consequences. With limited published studies among welders in low resource settings, we sought to determine the prevalence, pattern and factors associated with ocular disorders among small-scale welders in Katwe, Kampala.

Methods

In a field-based cross-sectional study, we recruited 343 small-scale welders. Simple random sampling was done to select the study participants. A pretested questionnaire was used to collect information on demographics, ocular, general history, systemic and ocular examination. The proportion of small-scale welders with ocular disorders (defined as any abnormal finding on eye examination) was determined. The bivariate and multivariate analyses were carried out, using logistic regression methods at a level of significance of 0.05.

Results

The mean age of the participants was 36 years (SD ± 12). The overall prevalence of ocular disorders was found to be 59.9%. The common ocular disorders included conjunctiva disorders (32%) and presbyopia (27%). There was a statistically significant relationship between females (OR = 4.279, P-value = 0.007), age 35 and above (OR = 4.244, P-value< 0.001), history of foreign body removal (OR = 1.677, P-value = 0.041), and ocular disorders.

Conclusions

There is a high prevalence of ocular disorders among small-scale welders. Conjunctiva disorders, presbyopia and myopia were the commonest. Being female, age 35 and above and foreign body removal, were significantly associated with ocular disorders among welders. Policies should be put in place to ensure all welders use proper personal -protective equipment (welding helmets), and also receive regular eye checkup and health education.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1150-x) contains supplementary material, which is available to authorized users.

Association between Blepharoptosis and Pterygium in Korea: A Population-Based Study during 2010-2012

PURPOSE

To investigate possible correlations between blepharoptosis and pterygium in a nationally representative sample of the Korean population.

METHODS

This population-based, cross-sectional study was comprised of 3,685 males and 4,792 females (≥ 19 years of age) participating in the fifth annual Korea National Health and Nutrition Examination Survey (KNHANES) from 2010 to 2012. The enrolled subjects underwent interviews, clinical examinations, and laboratory tests. Statistical tests were used to compare the prevalence of blepharoptosis, according to pterygium subtypes or pterygium existence. Multiple logistic regression analyses were also used to find the associations of blepharoptosis with pterygium.

RESULTS

Pterygium was present in 10.3% of males and 9.8% of females. The odds ratios (ORs) of pterygium in Korean males significantly decreased as the severity of blepharoptosis increased (p for trend = 0.0252). Using three models in multivariate analyses, males with blepharoptosis had an OR (95% confidence interval, (CI)) of 0.643 (0.435 ~ 0.951) for pterygium compared with males with no blepharoptosis, after adjusting for age, body mass index, smoking status, alcohol consumption, physical activity, serum vitamin D levels, diabetes mellitus, metabolic syndrome, high blood pressure, and stress intolerance. There was no significant association between blepharoptosis and females.

CONCLUSIONS

The association between blepharoptosis and pterygium in the Korean population showed a gender difference. Epidemiologic evidence only showed a negative correlation between blepharoptosis and pterygium in Korean males. Further studies are needed, therefore, to examine the sex difference in the pathogenesis of pterygium.

The Effect of Gender on Visual Field Sensitivity: The Singapore Chinese Eye Study

PURPOSE

Visual field (VF) sensitivity is known to be age-dependent, but there is a paucity of evidence on whether it is gender-dependent. We therefore investigated the effect of gender on VF sensitivity.

METHODS

An observational study involving 491 adults from the population-based Singapore Chinese Eye Study (SCES). Study participants underwent a comprehensive and standardised ocular examination and VF assessment on the Humphrey Field Analyzer II (Carl Zeiss Meditec, Inc., Dublin, CA, USA). The effect of gender on the mean deviation (MD) and pattern standard deviation (PSD) was analysed with linear regression models.

RESULTS

The mean age was 52.9 ± 5.9 years, and 229 (46.6%) participants were women. A total of 800 reliable VFs from 655 healthy eyes without visual impairment, glaucoma and significant cataract were included. The mean (± standard deviation) MD was -0.45 ± 1.01 dB in men, and -0.84 ± 1.20 dB in women. The MD [95% confidence interval] was 0.28 [-0.44 to -0.12] dB lower in females compared to males (P = 0.001) after adjusting for reliability indices, degree of lens opacity, and other potential confounders. The PSD was not significantly different between the genders.

CONCLUSIONS

In the SCES, the population-average of the central VF sensitivity was significantly lower in women compared to men by a small amount (0.28 dB). This effect was observed in healthy eyes, and was not explained by multiple potential confounders. Hence, this likely represents a physiological gender-based difference that is unaccounted for in standard automated perimetry. Further studies in other populations would be needed to corroborate our findings.

Association between pterygium, sun exposure, and serum 25-hydroxyvitamin in a nationally representative sample of Korean adults

Purpose

Ultraviolet-B (UVB) light exposure is the major risk factor for developing a pterygium, and serum 25-hydroxyvitamin D (25(OH)D) level is an objective measure of UVB light exposure. In this study, we investigated the association between pterygium, sun exposure, and serum 25(OH)D.

Methods

This population-based, cross-sectional study comprised 12,258 adults (aged ≥19 years) participating in the fifth annual Korea National Health and Nutrition Examination Survey from 2010 to 2012. The enrolled subjects underwent interviews, clinical examinations, and laboratory investigations. The serum 25(OH)D levels were measured, and pterygium was examined by using a slit lamp. We used three adjusted logistic regression models and selected covariates as potential confounders.

Results

The overall prevalence of pterygium was 7.09, and 53.1% of these subjects were women. The prevalence of pterygium was higher in elderly subjects and those who lived at low latitudes. In multivariate analysis with adjustment for confounding factors, subjects with a serum 25(OH)D level > 30 ng/mL, 25–30 ng/mL, and 15–20 ng/mL had an odds ratio (OR) (95% confidence interval [CI]) of 1.565 (1.035–2.366), 1.545 (1.086–2.198), 1.8 (1.358–2.386), and 1.535 (1.216–1.938), respectively, compared to those with a serum 25(OH)D level < 15 ng/mL. Subjects with a daily sun exposure > 5 h had an OR (95% CI) of 1.761 (1.395–2.223) compared to subjects with a daily sun exposure < 2 h.

Conclusion

The present study provides epidemiological evidence of an association of daily sun exposure and serum 25(OH)D levels with pterygium in a representative Korean population.

Ocular Exposure to Particulate Matter and Development of Pterygium: A Case-Control Study

Background:

Formation of pterygium has been mainly attributed to exposure to the ultraviolet (UV) radiation. Other factors such as dry weather, wind exposure and microtrauma with dust particles, have been linked to development of pterygium.

Objective:

To determine the association between ocular exposure to particulate matter and development of pterygium.

Methods:

This case-control study was conducted in a company dedicated to the production and marketing of toilets. We included a total of 90 cases identified in November 2013 and 184 controls. The diagnosis of pterygium was based on clinical examination. Variables studied included age and job tenure of the participants. Logistic regression analysis was used to assess the effect of exposure on developing pterygium.

Results:

All study participants were male. The mean age of the cases and controls was 39.9 (SD 9.5) and 37.8 (SD 7.3) years, respectively. 115 (42%) of the participants had a job tenure of 5–8 years. The percentages of cases and controls exposed to particulate matter were 31.1% (n=28) and 30.4% (n=56), respectively (OR 1.08, 95% CI 0.61 to 1.91).

Conclusion:

We could not observe any association between ocular exposure to particulate matter and development of pterygium.

Projection of Eye Disease Burden in Singapore

INTRODUCTION

Singapore's ageing population is likely to see an increase in chronic eye conditions in the future. This study aimed to estimate the burden of eye diseases among resident Singaporeans stratified for age and ethnicity by 2040.

MATERIALS AND METHODS

Prevalence data on myopia, epiretinal membrane (ERM), retinal vein occlusion (RVO), age macular degeneration (AMD), diabetic retinopathy (DR), cataract, glaucoma and refractive error (RE) by age cohorts and educational attainment from the Singapore Epidemiology of Eye Diseases (SEED) study were applied to population estimates from the Singapore population model.

RESULTS

All eye conditions are projected to increase by 2040. Myopia and RE will remain the most prevalent condition, at 2.393 million (2.32 to 2.41 million) cases, representing a 58% increase from 2015. It is followed by cataract and ERM, with 1.33 million (1.31 to 1.35 million), representing an 81% increase, and 0.54 million (0.53 to 0.549 million) cases representing a 97% increase, respectively. Eye conditions that will see the greatest increase from 2015 to 2040 in the Chinese are: DR (112%), glaucoma (100%) and ERM (91.4%). For Malays, DR (154%), ERM (136%), and cataract (122%) cases are expected to increase the most while for Indians, ERM (112%), AMD (101%), and cataract (87%) are estimated to increase the most in the same period.

CONCLUSION

Results indicate that the burden for all eye diseases is expected to increase significantly into the future, but at different rates. These projections can facilitate the planning efforts of both policymakers and healthcare providers in the development and provision of infrastructure and resources to adequately meet the eye care needs of the population. By stratifying for age and ethnicity, high risk groups may be identified and targeted interventions may be implemented.

Protective effect of smoking against pterygium development in men: a nationwide longitudinal cohort study in South Korea

OBJECTIVE

The present study aimed to evaluate the association between smoking and incident pterygium in adult Korean men.

DESIGN

A retrospective nationwide longitudinal cohort.

SETTING

National Health Insurance database of South Korea.

PARTICIPANTS

This study included Korean men (age range: 40-79 years) registered in the Korea National Health Insurance Service database from 2002 through 2013. We compared HRs for pterygium between 90 547 current/past and 90 547 never-smokers via 1:1 propensity-matched analysis.

PRIMARY OUTCOME MEASURE

Incident cases of pterygium were identified from the database.

RESULTS

Pterygium developed in 5389 (6.0%) never-smokers and 3898 (4.3%) past/current smokers (P<0.001). The incidence of pterygium per 1000 person-years in never-smokers and in past/current smokers was 6.5 and 4.7, respectively (age-adjusted HR, 0.73; 95% CI, 0.70 to 0.76). This protective effect was more pronounced among current smokers than among past smokers (for current smokers: HR, 0.68; 95% CI, 0.65 to 0.71 and for past smokers: HR, 0.85; 95% CI, 0.80 to 0.90). A longer duration of smoking and higher amounts of cigarette consumption were associated with a lower incidence of pterygium.

CONCLUSIONS

Longitudinally, cigarette smoking was associated with a reduced risk of pterygium, and this protective effect was more pronounced among current smokers than among past smokers.

Prevalence and factors associated with age-related macular degeneration in a southwestern island population of Japan: the Kumejima Study

AIMS

To evaluate the prevalence of and factors associated with age-related macular degeneration (AMD) in a rural population of southwestern Japan.

METHODS

This population-based cross-sectional study of all residents aged 40 years or older was conducted on the island of Kumejima, Okinawa, Japan. Of 4632 eligible residents, 3762 completed a comprehensive questionnaire and underwent ocular examination (participant rate, 81.2%). A non-mydriatic fundus photograph was used to grade AMD lesions according to the Wisconsin protocol. Prevalence of AMD was calculated and factors associated with AMD were identified by logistic regression.

RESULTS

Of 3068 subjects with gradable photographs, 469 had early AMD and 4 had late AMD. Age-adjusted prevalence was 13.4% for any AMD, 13.3% for early AMD and 0.09% for late AMD. In multivariate analysis, any AMD was positively associated with age (OR 1.04 per year, 95% CI 1.03 to 1.05), male sex (OR 1.42, 95% CI 1.14 to 1.75) and history of cataract surgery (OR 1.35, 95% CI 1.00 to 1.82) and was negatively associated with longer axial length (OR 0.85 per millimetre, 95% CI 0.74 to 0.96). Early AMD similarly showed significant associations with these same factors.

CONCLUSIONS

Prevalence of early or late AMD in a southwestern island population of Japan was 13.4% or 0.09%. Our data suggest relatively high prevalence for early AMD and low prevalence for late AMD in this sample of rural Japanese population. Significant factors associated with any or early AMD were mostly similar to that of previous studies.

Autophagy mediates cell cycle response by regulating nucleocytoplasmic transport of PAX6 in limbal stem cells under ultraviolet-A stress

Limbal stem cells (LSC) account for homeostasis and regeneration of corneal epithelium. Solar ultraviolet A (UVA) is the major source causing oxidative damage in the ocular surface. Autophagy, a lysosomal degradation mechanism, is essential for physiologic function and stress defense of stem cells. PAX6, a master transcription factor governing corneal homeostasis by regulating cell cycle and cell fate of LSC, responds to oxidative stress by nucleocytoplasmic shuttling. Impaired autophagy and deregulated PAX6 have been reported in oxidative stress-related ocular surface disorders. We hypothesize a functional role for autophagy and PAX6 in LSC’s stress response to UVA. Therefore, human LSC colonies were irradiated with a sub-lethal dose of UVA and autophagic activity and intracellular reactive oxygen species (ROS) were measured by CYTO-ID assay and CM-H₂DCFDA live staining, respectively. Following UVA irradiation, the percentage of autophagic cells significantly increased in LSC colonies while intracellular ROS levels remained unaffected. siRNA-mediated knockdown (KD) of ATG7 abolished UVA-induced autophagy and led to an excessive accumulation of ROS. Upon UVA exposure, LSCs displayed nuclear-to-cytoplasmic translocation of PAX6, while ATG7KD or antioxidant pretreatment largely attenuated the intracellular trafficking event. Immunofluorescence showing downregulation of proliferative marker PCNA and induction of cell cycle regulator p21 indicates cell cycle arrest in UVA-irradiated LSC. Abolishing autophagy, adenoviral-assisted restoration of nuclear PAX6 or antioxidant pretreatment abrogated the UVA-induced cell cycle arrest. Adenoviral expression of an ectopic PAX gene, PAX7, did not affect UVA cell cycle response. Furthermore, knocking down PAX6 attenuated the cell cycle progression of irradiated ATG7KD LSC by de-repressing p21 expression. Collectively, our data suggest a crosstalk between autophagy and PAX6 in regulating cell cycle response of ocular progenitors under UVA stress. Autophagy deficiency leads to impaired intracellular trafficking of PAX6, perturbed redox balance and uncurbed cell cycle progression in UVA-stressed LSCs. The coupling of autophagic machinery and PAX6 in cell cycle regulation represents an attractive therapeutic target for hyperproliferative ocular surface disorders associated with solar radiation.

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

BACKGROUND

Pterygium is a common chronic ophthalmic condition, which may result in significant visual morbidity or lead to blindness in extreme cases. The prevalence of pterygium in China has not been reported at the sub-national level.

METHODS

In this study, we conducted a systematic review and meta-analysis to estimate the prevalence of pterygium in China. China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Biomedicine Literature Database (CBM-SinoMed), PubMed, Embase and Medline were searched before September 2016. We performed a multilevel mixed-effect meta-regression based on the included studies, our results showed that age, gender and latitude were significantly associated with pterygium prevalence. Based on the final model, the age and gender-specific prevalence of pterygium in 31 Chinese provinces (except Hongkong, Macau and Taiwan) and the whole country was generated.

RESULTS

In 2010, the overall prevalence of pterygium in Chinese people aged 15-84 years was 9.84% (95% CI: 6.72-14.14), and the number of pterygium cases in China was 108.65 million (95% CI: 74.23-156.13).

CONCLUSIONS

In conclusion, the prevalence of pterygium in Chinese population in 2010 was estimated at both the national and provincial levels. The higher burden of pterygium across the country calls for efforts to advocate public health education encouraging people to take appropriate protective measures.

The incidence and prevalence of pterygium in South Korea: A 10-year population-based Korean cohort study

Although numerous population-based studies have reported the prevalences and risk factors for pterygium, information regarding the incidence of pterygium is scarce. This population-based cohort study aimed to evaluate the South Korean incidence and prevalence of pterygium. We retrospectively obtained data from a nationally representative sample of 1,116,364 South Koreans in the Korea National Health Insurance Service National Sample Cohort (NHIS-NSC). The associated sociodemographic factors were evaluated using multivariable Cox regression analysis, and the hazard ratios and confidence intervals were calculated. Pterygium was defined based on the Korean Classification of Diseases code, and surgically removed pterygium was defined as cases that required surgical removal. We identified 21,465 pterygium cases and 8,338 surgically removed pterygium cases during the study period. The overall incidences were 2.1 per 1,000 person-years for pterygium and 0.8 per 1,000 person-years for surgically removed pterygium. Among subjects who were ≥40 years old, the incidences were 4.3 per 1,000 person-years for pterygium and 1.7 per 1,000 person-years for surgically removed pterygium. The overall prevalences were 1.9% for pterygium and 0.6% for surgically removed pterygium, and the prevalences increased to 3.8% for pterygium and 1.4% for surgically removed pterygium among subjects who were ≥40 years old. The incidences of pterygium decreased according to year. The incidence and prevalence of pterygium were highest among 60–79-year-old individuals. Increasing age, female sex, and living in a relatively rural area were associated with increased risks of pterygium and surgically removed pterygium in the multivariable Cox regression analysis. Our analyses of South Korean national insurance claims data revealed a decreasing trend in the incidence of pterygium during the study period.

Risk Factors for Pterygium in Ilam Province, Iran

Purpose:

To evaluate the risk factors for pterygium in the dry, high altitude province of Ilam, Iran.

Methods:

The study included patients who presented to ophthalmology clinic. The patients were divided into two groups: 210 diagnosed with pterygium or pinguecula (unilateral or bilateral), and 210 healthy controls. Demographic variables, living environment, disease type, disease laterality, family history of pterygium as well as history of smoking, working outdoors, baking, welding, ocular conditions (trachoma keratopathy, glaucoma, refractive error, and dry eye), use of glasses, ultraviolet light exposure, and systemic conditions were collected from both groups and compared for risk assessment.

Results:

Univariate analysis revealed that age (P = 0.001), sex (P = 0.001), family history of pterygium (P = 0.001), positive history of smoking (P < 0.001), history of baking (P = 0.045), welding experience (P < 0.001), severe blepharitis (P < 0.001), hyperopia (P < 0.001), dry eye (P < 0.001), hypertension (P < 0.001), ischemic heart disease (P < 0.001), obesity (P = 0.038), and primary residential area (P = 0.025) had significant associations with increased incidence of pterygium. However, in multivariate analysis, only family history of pterygium, cigarette smoking, history of baking, age, and severe blepharitis were significantly associated with the incidence of pterygium (P<0.001, P<0.001, P = 0.002, P = 0.023 and P = 0.002, respectively).

Conclusion:

This study tested more risk factors related to the prevalence of pterygium compared to previous studies. It also confirmed previously established risk factors. Family history of pterygium and blepharitis were risk factors that have not been reported in previous studies and were found to be significantly associated with the development of pterygium in this study.

Association between pterygium and obesity status in a South Korean population

This study examined the association between pterygium and obesity status by examining a nationally representative sample of South Korean adults.This population-based, cross-sectional study comprised 16,234 adults (aged ≥19 years) who had participated in the fifth annual Korea National Health and Nutrition Examination Survey from 2010 to 2012. The enrolled subjects underwent interviews, clinical examinations, and laboratory investigations. We compared body mass index (BMI) and waist circumference (WC), according to the presence of pterygium. Multiple logistic regression analysis was conducted to examine the associations of each obesity parameter with pterygium after adjusting for age, smoking status, alcohol consumption, physical activities, educational levels, outdoor occupation, area of residence, and daily sun exposure duration.The prevalence rate of pterygium tended to increase as the BMI increased only in women, and both male and female subjects with higher WC were likely to have more pterygium in both sexes. In the multivariate analysis, overweight women had an odd ratio (OR) (95% confidence interval (CI)) of 1.16 (0.86-1.55) and obese women had an OR (95% CI) of 1.35 (1.02-1.77) compared to women with normal weight (P for trend for ORs = 0.04). Compared to women without abdominal obesity, abdominally obese women had an OR (95% CI) of 1.26 (1.01-1.58). There was no significant association between obesity and pterygium in men.The present study provides epidemiologic evidence of an association between obesity and pterygium in women. Further studies are needed to examine the sex difference in the pathogenesis of pterygium.

The prevalence and risk factors for pterygium in South Korea: the Korea National Health and Nutrition Examination Survey (KNHANES) 2009-2010

OBJECTIVES

To determine the prevalence and risk factors for pterygium in the adult Korean population of South Korea.

METHODS

Data were analyzed from 9,193 participants who were 40 years of age or older from the Korea National Health and Nutrition Examination Survey (KNHANES), conducted from 2009 to 2010. Standardized slit-lamp examinations were performed by study ophthalmologists to examine the anterior segment for evidence of pterygium. Pterygium was graded clinically as T1 (atrophic), T2 (intermediate), or T3 (opaque). Every participant underwent ocular and systemic examinations, as well as interviewer-administered questionnaires. Any evidence of pterygium and observed association between the risk factors were recorded.

RESULTS

The mean age of the subjects was 55.7 (±0.2) years. Of the 9,193 eligible subjects, 935 had pterygium in at least one eye. In a multivariate logistic regression analysis adjusted for age and sex, pterygium was significantly associated with rural vs. urban residence (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.4 to 2.0), lower level of education (OR, 4.5; 95% CI, 3.1 to 6.6), low income (OR, 1.3; 95% CI, 1.0 to 1.8), smoking (OR, 0.7; 95% CI, 0.5 to 1.0), and more hours of sun exposure (OR, 1.5; 95% CI, 1.2 to 1.8). After adjusting for all variables, the prevalence of pterygium was significantly associated with age, sex, residence, education level, and smoking.

CONCLUSIONS

This is a nationwide epidemiologic study in South Korea to assess the prevalence of and risk factors for pterygium. The overall prevalence of pterygium was 8.8% among Koreans aged 40 years or older. Older age, male gender, rural residence, lower level of education, and non-smoking were associated with the development of pterygium.

Design and baseline characteristics of a population-based study of eye disease in southern Chinese people: the Dongguan Eye Study

BACKGROUND

To describe the study design, methodology and baseline characteristics of the Dongguan Eye Study.

DESIGN

Population-based, cross-sectional study

PARTICIPANTS

A total of 8952 rural-dwelling residents aged 40 years or older in Hengli, Dongguan.

METHODS

The Dongguan Eye Study was conducted from September 2011 to February 2012. The interview covered demographic data, socio-economic status and health- and vision-related quality of life. Physical measurements included height, weight, waist and hip circumference, heart rate and blood pressure. Laboratory tests included fasting blood glucose, haemoglobin A1c, oral glucose tolerance, serum total cholesterol, triglycerides, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, serum creatinine, blood urea nitrogen and uric acid. Ophthalmic examinations included visual acuity and autorefraction testing, intraocular pressure measurement, slit-lamp examination, ocular biometry, gonioscopy, fundus photography, retinal nerve fibre layer imaging and visual field testing.

MAIN OUTCOME MEASURES

Prevalence and risk factors for visual impairment, blindness, eye diseases and their associations with systemic medical indicators or health-related lifestyles, as well as epidemiological data on diabetic subjects. Methodology, response rates and baseline characteristics are presented.

RESULTS

Of the 11 357 individuals eligible for the Dongguan Eye Study, 8952 (78.82%) subjects participated. All participants were self-identified Han Chinese. The average age was 54.0 years, 59.9% were female, 48.4% were farmers and 77.2% had elementary or junior middle school educational levels. The average body mass index and waist-hip ratio were 24.6 ± 3.9 kg/m(2) and 0.9 ± 0.2.

CONCLUSIONS

Data from the Dongguan Eye Study provide information concerning the prevalence, risk factors and impacts of eye diseases in rural residents undergoing urbanization in southern China.

Results of pterygium excision adjunct with conjunctival autograft transplantation for primary pterygium by ophthalmology trainees

To evaluate the results of pterygium excision with conjunctival autograft transplantation for primary pterygium performed by trainee ophthalmologists. Design Prospective interventional case series. Setting A tertiary eye care center in northern Thailand. Participants Patients with primary pterygium recruited from July 2011 to August 2012. Intervention In all cases, the affected eye underwent pterygium excision followed by a superior conjunctival autograft carried out by trainee ophthalmologists. Main outcome measure The recurrence of pterygium and other post-operative complications. Results Sixty-two eyes from 54 patients were studied. There were 36 females (66.7 %) and 18 males (33.3 %). The mean age of the patients was 54.5 (±9.8) years with the mean corneal invasion measured at 3.3(±0.8) mm. Pterygium morphologies of Grade 1, Grade 2, and Grade 3 were 33.9, 48.4, and 17.7 %, respectively, with the mean follow-up time of 17.3 (±7.9) months. Pterygium recurred in the cornea of six eyes (9.7 %). All recurrences occurred within 6-month post-operation. Other post-operative complications included conjunctival recurrence (4.8 %), graft retraction (3.2 %), conjunctival cyst (3.2 %), and increased intraocular pressure (1.6 %). The recurrence of pterygium was not associated with the patient age (p = 0.72), occupation (p = 0.23), sun exposure time (p = 0.18), pterygium duration (p = 0.22), pterygium size (p = 0.67), or pterygium morphology (p = 0.85). Conclusion The recurrence rate and post-operative complications of pterygium excision with conjunctival autograft performed by trainee ophthalmologists were within acceptable limits. All recurrence occurred within 6 months after surgery.

Monitor corneal epithelial healing under bandage contact lens using ultrahigh-resolution optical coherence tomography after pterygium surgery

OBJECTIVE

To monitor corneal epithelial healing under bandage contact lens (BCL) using ultrahigh-resolution optical coherence tomography (UHR-OCT) after pterygium surgery.

METHODS

Thirty-nine eyes of 39 patients undergoing pterygium excision and conjunctival autografting were randomly allocated into 2 groups: 20 eyes were covered with silicone hydrogel BCLs at the end of surgery and 19 eyes served as a control. Ultrahigh-resolution optical coherence tomography scans of the cornea were performed sequentially at 1, 2, and 3 days, and then every other day until the end of re-epithelialization after surgery. Complete epithelial healing was verified with fluorescein staining examination after removal of BCLs. Postsurgery pain was evaluated using the visual analog scale.

RESULTS

All BCLs were successfully fit without any contact lens-related complications. Ultrahigh-resolution optical coherence images clearly revealed the architectural features of postoperative cornea with BCL in situ and showed epithelial healing process. Ultrahigh-resolution optical coherence tomography imaging agreed with the fluorescein staining examinations in detecting corneal epithelial defect. Based on the assessment by UHR-OCT, the average time course of re-epithelialization in the BCL group was 3.9±1.2 days, whereas in the control group, it was 5.7±1.8 days (P=0.001). Visual analog scale scoring showed lower pain levels in the BCL group comparing with the control group at each point of time (all P<0.05).

CONCLUSIONS

Ultrahigh-resolution optical coherence tomography is an excellent tool in monitoring corneal epithelial healing under BCLs and determining the appropriate time for lens removal. Silicone hydrogel BCL is recommended as an adjuvant therapy after pterygium surgery for its efficacy in improving re-epithelialization and postoperative comfort.

Epidemiology and Associated Morbidity of Pterygium: A Large, Community-Based Case-Control Study

BACKGROUND

To evaluate the prevalence and risk factors of various conditions among patients with pterygium.

METHODS

A retrospective observational case control study of 4,037 patients who were diagnosed with pterygium in the Central District of Clalit Health Services in Israel from 2000-2009. A total of 16,054 randomly selected controls from the district HMO members. Personal, medical, and demographic information were extracted from patients' files. We calculated the prevalence of various ocular, systemic, and demographic conditions as risk factors for pterygium.

RESULTS

The average age of pterygium patients was 58.4 ± 14 years; 56.9% were male. A significant tendency to develop pterygium was found among individuals of lower socioeconomic status (p < 0.001) and in populations living in rural areas (p < 0.001). A logistic regression model adjusted to marital status, socio-economic class, and area of living was performed. The following conditions were significantly associated with pterygium: blepharitis (OR = 1.71; 99.9% CI: 1.53-1.93), chalazia (OR = 1.46; 99.9% CI: (1.19-1.78)), anxiety (OR = 1.14, 99.9% CI: 0.98-1.33), and G6PD deficiency (OR = 1.85; 99.9% CI: 1.11-3.07). Schizophrenia (OR 0.31; 99.9% CI: 0.19-0.50) and smoking (OR 0.82; 99.9% CI: 0.76-0.89) were significantly less prevalent among pterygium patients.

CONCLUSIONS

Pterygium etiology is multifactorial. Some demographic, systemic, and periocular conditions are significantly more prevalent and some are less prevalent among pterygium patients. Better understanding of the pathophysiological association between those diseases and pterygium may help in its prevention and treatment.

Prevalence of and risk factors for pterygia in a rural Northern Chinese population

PURPOSE

To determine the prevalence of and associated risk factors for pterygia development in a high-latitude-dwelling Northern Chinese population.

METHODS

A prospective population-based survey was conducted between November 2008 and July 2009. A stratified, clustered, randomized sampling procedure was used to select 8445 subjects, aged ≥18 years, all with diagnosed, graded pterygia. Risk factors associated with the occurrence of pterygia were evaluated according to logistic regression models.

RESULTS

A total of 8445 residents (aged 18-94 years) from the Heilongjiang Province, China, participated in the study. Of these, 208 (2.5%) had at least one diagnosed pterygium. The prevalence of bilateral pterygia was 1.2% (95% confidence interval, CI, 1.0-1.4%). According to multivariable analysis, pterygia were significantly more likely to occur in persons aged 70-94 years than in those aged 18-39 years (odds ratio, OR, 29.0, 95% CI 13.6-61.6, p < 0.01). Pterygia were significantly associated with male sex (OR 1.9, 95% CI 1.4-2.6, p < 0.01) and outdoor work (OR 1.8, 95% CI 1.2-2.6, p < 0.01). Multivariable analysis indicated that pterygia were not associated with smoking status (OR 1.0, 95% CI 0.8-1.4) or alcohol intake (OR 1.0, 95% CI 0.7-1.4, p > 0.05).

CONCLUSIONS

This study details the occurrence of and risk factors for pterygia in a Chinese population residing in a rural, high-latitude, cold-climate area of Northern China. The primary risk factors for pterygia were age, male sex, and outdoor work.

Seasonal effects on pterygium surgery outcome: implications for the role of sunlight exposure

PURPOSE

The aim of this study was to compare the results of pterygium surgery in patients when performed in the summer with the results of surgery performed in the winter.

METHODS

This retrospective study enrolled 55 eyes of 53 patients with primary pterygia who underwent a surgery between December 2011 and January 2012 (winter group, 32 eyes) or between June and July 2012 (summer group, 23 eyes). All the patients were followed up for at least 1 year. Pterygium recurrence, ocular discomfort, persistent conjunctival inflammation, and graft complications were evaluated postoperatively.

RESULTS

There was no significant difference between the groups in terms of age or gender. All the patients were farmers in rural areas. The overall pterygium recurrence rate was 14.5% (8 of 55 eyes). The recurrence rate in the summer group was significantly higher than in the winter group (26.1% vs. 6.2%, P = 0.048). Persistent conjunctival inflammation was also significantly higher in the summer group than in the winter group (30.4% vs. 6.2%, P = 0.022). Pterygium recurrence was significantly higher in eyes with persistent conjunctival inflammation than in eyes without inflammation (66.6% vs. 4.3%, P < 0.001). Mild and moderate ocular discomfort was significantly more frequent in the summer group than in the winter group (69.5% vs. 34.3%, P = 0.01).

CONCLUSIONS

Pterygium recurrence rates were higher, and postsurgical discomfort was more common when pterygium surgery was performed in the summer compared with that in the winter, potentially because of the increased exposure to sunlight during the summer.

Prevalence and risk factors for pterygium in rural older adults in Shandong Province of China: a cross-sectional study

To investigate the prevalence and risk factors for pterygium in rural older adults in Shandong Province, eastern China, a population-based, cross-sectional study was performed from April to July 2008. By means of cluster random sampling methods, a total of 19,583 people aged 50 years or above were randomly selected from four rural counties. Out of 19,583 people, 1,767 residents were excluded mainly because they were migrant workers when this study was performed. Finally, 17,816 (90.98%) people were included as eligible subjects. They received a comprehensive eye examination and a structured questionnaire voluntarily. Patients with pterygium were defined as having pterygium at the time of survey or pterygium surgery had been performed. 1,876 people were diagnosed as pterygium, either unilateral (1,083) or bilateral (793), which is equivalent to a prevalence of 10.53% (95% CI, 10.08–10.98). The multivariate logistic regression analysis showed that pterygium was independently associated with older age, areas, outdoor time, educational level, and use of hat and/or sunglasses. The prevalence of pterygium increased with age and hours spent under sunshine per day. Meanwhile, the higher the educational level and the more use of hat and/or sunglasses, the lower the pterygium prevalence.

Risk factors associated with pterygium and its subtypes in Korea: the Korean National Health and Nutrition Examination Survey 2008-2010

PURPOSE

To assess the sociodemographic and health-related risk factors associated with pterygium and its subtypes in Korea.

METHODS

From 2008 to 2010, a total of 14,920 randomly selected national representative participants of the Korean National Health and Nutrition Examination Survey underwent additional ophthalmologic examinations by the Korean Ophthalmologic Society. The risk factors for pterygium in general or according to subtype (atrophic, intermediate, and fleshy) were identified using multivariate logistic regression analysis.

RESULTS

The prevalence of pterygium was 6.7% (95% confidence interval, 5.9-7.5) in subjects aged 30 years or older. Older age, male sex, lower educational level, rural habitation, nonsmoking, and sun exposure were independent risk factors for pterygium. Among subjects with pterygium, older age, male sex, lower educational level, and nonsmoking were independent risk factors for all types of pterygium. Sun exposure for >5 h/d was the independent risk factor for the severe pterygium subtype.

CONCLUSIONS

Socioeconomic disparities in pterygium development exist. Proper ocular examination and education to avoid excessive sun exposure would be helpful in reducing disease risk.

Prevalence and associated factors for pterygium in rural agrarian central India. The central India eye and medical study

Purpose

To evaluate the prevalence of pterygia and associated factors in a rural population in a mostly undeveloped agrarian region.

Methods

The Central India Eye and Medical Study is a population-based study performed in a rural region of Central India. The study comprised 4711 subjects (aged 30+ years). A detailed ophthalmic and medical examination was performed. A pterygium was diagnosed during the slit lamp examination and confirmed on corneal photographs. It was defined as a fleshy fibrovascular growth, crossing the limbus and typically seen on the nasal, and sometimes temporal, conjunctiva.

Results

A pterygium was detected in 798 eyes (prevalence rate: 8.47±0.29%) of 608 (12.91±0.49%) subjects. Bilateral pterygia were present in 190 subjects (4.0% of study population). Pterygia prevalence increased from 6.7±0.8% in the age group 30-39 years, to 13.5±1.2% in the age group 50-59 years, to 25.3±2.1% in the age group 70-79 years. Prevalence of pterygia was associated with older age (P<0.001; regression coefficient B: 0.02; odds ratio (OR): 1.02; 95%CI: 1.01, 1.03), male gender (P<0.001;B:-0.73;OR: .48;95%CI:0.39,0.61), lower level of education (P<0.001;B:-0.30;OR:0.74;95%CI:0.69,0.80), lower body height (P=0.001;B:-0.02;OR:0.98;95%CI:0.97,0.99), and higher cylindrical refractive error (P<0.001;B:0.23;OR:1.26;95%CI:1.18,1.34). If the education level was dropped, the number of hours spent with vigorous activity outdoors (P=0.001;B:0.001;OR:1.001;95%CI:1.000,1.0001) was significantly associated with the prevalence of pterygia, in addition to older age (P<0.001;B:0.03;OR:1.03;95%CI:1.03,1.04), male gender (P<0.001;B:-0.49;OR:0.62;95%CI:0.49,0.77), lower body height (P=0.005;B:-0.02;OR:0.98;95%CI:0.97,0.99), and higher cylindrical refractive error (P<0.001;B:0.23;OR:1.25;95%CI:1.18,1.34).

Conclusions

Pterygium prevalence in rural Central India is about 13% among adult Indians aged 30+ years. Older age, male gender, lower educational level, lower body height and more time spent outdoors with vigorous work were associated factors. Since the living conditions in the study location were mostly untouched by modern developments, the results may show the prevalence and associations of pterygia without major medical or technologic influences.

Geographical prevalence and risk factors for pterygium: a systematic review and meta-analysis

OBJECTIVE

Pterygium is considered to be a proliferative overgrowth of bulbar conjunctiva that can induce significant astigmatism and cause visual impairment; this is the first meta-analysis to investigate the pooled prevalence and risk factors for pterygium in the global world.

DESIGN

A systematic review and meta-analysis of population-based studies.

SETTING

International.

PARTICIPANTS

A total of 20 studies with 900 545 samples were included.

PRIMARY OUTCOME MEASURE

The pooled prevalence and risk factors for pterygium.

RESULTS

20 studies were included. The pooled prevalence of pterygium was 10.2% (95% CI 6.3% to 16.1%). The pooled prevalence among men was higher than that among women (14.5% vs 13.6%). The proportion of participants with unilateral cases of pterygium was higher than that of participants with bilateral cases of pterygium. We found a trend that the higher pooled prevalence of pterygium was associated with decreasing geographical latitude and age in the world. The pooled OR was 2.32 (95% CI 1.66 to 3.23) for the male gender and 1.76 (95% CI 1.55 to 2.00) for outdoor activity, respectively.

CONCLUSIONS

The pooled prevalence of pterygium was relatively high, especially for low latitude regions and the elderly. There were many modifiable risk factors associated with pterygium to which healthcare providers should pay more attention.

Prevalence and associated factors for pterygium in a rural adult population (the Southern Harbin Eye Study)

PURPOSE

To estimate the prevalence of pterygium and identify associated risk factors in a Southern Harbin population at low altitude in a cold climate.

METHODS

A prospective population-based survey was conducted in 2006. A stratified, clustered, randomized sampling procedure was used to select 5057 subjects aged 50 years and older. Pterygia were diagnosed and graded, and the association between pterygium and astigmatism was investigated. Risk factors associated with pterygium were evaluated with logistic regression models.

RESULTS

A total of 5057 persons aged 50 to 96 years (91.0% of the eligible population) who were residents of Southern Harbin, Heilongjiang Province, China, participated in the study, and 323 (6.4%) had at least 1 pterygium. The prevalence of pterygium in the unilateral and bilateral eyes of the participants was 3.7% and 2.6%, respectively. The presence of a pterygium was significantly associated with the presence of astigmatism (cylinder ≥ ± 0.5 diopters, P < 0.001). Pterygium was independently associated with male sex (odds ratio 1.73; 95% confidence interval, 1.37-2.19) and smoking (odds ratio 1.90; 95% confidence interval, 1.51-2.35) (P < 0.001).

CONCLUSIONS

This study details pterygium in a rural population of Harbin at low altitude in a cold climate. The prevalence of pterygium in the population is lower than that reported in other regions of the world. The primary causative factors were related to male sex and smoking, the latter of which is easily preventable. Public health schemes to address this serious health issue are urgently needed.