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

A model of ocular ambient irradiance at any head orientation

Exposure to ambient ultraviolet radiation is associated with various ocular pathologies. Estimating the irradiance received by the eyes is therefore essential from a preventive perspective and to study the relationship between light exposure and eye diseases. However, measuring ambient irradiance on the ocular surface is challenging. Current methods are either approximations or rely on simplified setups. Additionally, factors like head rotation further complicate measurements for prolonged exposures. This study proposes a novel numerical approach to address this issue by developing an analytical model for calculating irradiance received by the eye and surrounding ocular area. The model takes into account local ambient irradiance, sun position, and head orientation. It offers a versatile and cost-effective means of calculating ocular irradiance, adaptable to diverse scenarios, and serves both as a predictive tool and as a way to compute correction factors, such as the fraction of diffuse irradiance received by the eyes. Furthermore, it can be tailored for prolonged durations, facilitating the calculation of radiant dose obtained during extended exposures.

Risk factors for pterygium: Latest research progress on major pathogenesis

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

Low Rate of Postoperative Pterygium Recurrence in Patients under Treatment with Low-Dose Oral Doxycycline for Chronic Blepharitis: A First Report

PURPOSE

Low doses of systemic doxycycline (LD-SD) inhibit angiogenesis and the expression of matrix metalloproteases, which are determinants of pterygium progression. This study aimed to compare the recurrence rate and visual outcome of pterygium excision in patients undergoing chronic treatment with LD-SD for chronic refractory blepharitis and LD-SD-naive patients.

METHODS

A retrospective analysis of patients that underwent surgical excision and conjunctival graft apposition was conducted. Patients were divided in a TETRA group (under LD-SD treatment at the moment of surgery) and a control group. The main outcome was the rate of recurrence at 1 year postoperatively. Secondary outcomes were the comparisons of surface regularity, visual quality, and dry-eye symptoms at 6-week, 6-month, and 1-year follow-up in the two groups.

RESULTS

The TETRA group showed a significantly lower rate of 1-year recurrence both in primary (p = 0.034) and recurrent (p < 0.001) pterygia. The best corrected visual acuity (BCVA), astigmatic error, corneal total root mean square (RMS), and ocular surface disease index (OSDI) significantly reduced during the follow-up in both groups. The surface asymmetry index and high-order aberrations (HOAs) significantly reduced only in the TETRA group. The final BCVA was significantly higher, while the OSDI score and total RMS and HOAs were significantly lower in the TETRA group compared to the control.

CONCLUSIONS

Patients under treatment with LD-SD showed a lower rate of recurrence at 1-year follow-up compared to controls. These patients also experienced higher BCVA and surface regularity and less dry-eye symptoms.

Contribution of Matrix Metalloproteinase-2 Genotypes to Taiwan Pterygium Risk

BACKGROUND/AIM

In the literature, the studies about the role of matrix metalloproteinase-2 (MMP-2) in pterygium diagnosis are mainly based on its protein expression. The role of MMP-2 variants has never been examined. The aim of this study was to examine the association of MMP-2 genotypes with pterygium risk.

MATERIALS AND METHODS

MMP-2 rs243865 and rs2285053 were genotyped in 140 pterygium cases and 280 non-pterygium controls by typical polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping technology.

RESULTS

The genotypic frequency of MMP-2 rs243865 CC, CT and TT were 86.4%, 12.9% and 0.7% in the pterygium group and 81.1%, 17.1% and 1.8% in the non-pterygium group (p for trend=0.3389). The variant CT and TT carriers had a 0.70- and 0.38-fold pterygium risk (95%CI=0.39-1.26 and 0.04-3.25, p=0.2982 and 0.6686, respectively). As for MMP-2 rs2285053, the genotypic frequency of CC, CT and TT were 67.1%, 28.6% and 4.3% in the pterygium group, non-significantly different from those in non-pterygium group (p for trend=0.7081). The CT and TT carriers had a 0.88- and 0.71-fold pterygium risk (95%CI=0.56-1.38 and 0.27-1.88, p=0.6612 and 0.6456, respectively). The allelic analysis results showed that MMP-2 rs243865 variant T allele was not associated with pterygium risk (7.1% versus 10.4%, OR=0.67, 95%CI=0.39-1.13, p=0.1649). As for MMP-2 rs2285053, the T allele was not associated with pterygium risk either (18.6% versus 21.1%, OR=0.85, 95%CI=0.59-1.23, p=0.4136).

CONCLUSION

The genotypes at MMP-2 rs243865 or rs2285053 played minor role in determining individual susceptibility for pterygium among Taiwanese.

Subconjunctival dexamethasone-assisted conjunctival autograft harvesting versus normal saline during pterygium surgery - A randomized clinical trial

PURPOSE

To evaluate the effect of subconjunctival dexamethasone compared to normal saline on conjunctival autograft harvesting in patients undergoing pterygium surgery.

METHODS

Fifty-two eyes of 52 patients who underwent pterygium excision combined with autologous conjunctival graft (CAG) using releasable suture were included in this prospective interventional study. The patients were randomized into two groups of 26 patients each. Group A consisted of patients in whom CAG was harvested using subconjunctival 0.5 ml of 0.4% dexamethasone sodium phosphate and in group B patients, normal saline was used. The patients were assessed for postoperative pain, foreign body sensation, and watering as the subjective signs of inflammation and conjunctival inflammation and lid edema as the objective signs of inflammation at 12 and 24 h postsurgery.

RESULTS

The mean age of group A and B patients was 47.69 + 13.09 and 46.00 + 10.76 years, respectively. The male:female ratio was 1.6:1 in group A and 1.1:1 in group B. The mean surgical time in group A was 243.96 ± 52.13 s and in group B was 258.08 ± 43.99 s. Postoperative pain, foreign body sensation, and watering were significantly lower in group A patients than in group B patients at both 12 and 24 h postoperatively (group A: 4.65 ± 1.33, 4.88 ± 1.73, and 3.85 ± 1.43, respectively, at 12 h; 1.89 ± 1.03, 1.69 ± 1.09, and 1.69 ± 0.97, respectively, at 24 h and group B: 6.42 ± 0.95, 6.65 ± 0.98, and 6.27 ± 1.40, respectively, at 12 h; 3.27 ± 1.43, 3.12 ± 1.25, 2.58 ± 1.14, respectively, at 24 h) ( P < 0.001). Conjunctival inflammation was significantly lower in group A at 12 h ( P < 0.05) and 24 h ( P < 0.05) after surgery compared to group B. Lid edema failed to show any significant ( P = 0.17) difference with respect to severity in both the groups at 12 and 24 h ( P = 0.699).

CONCLUSION

Subconjunctival dexamethasone decreased patient discomfort following pterygium surgery. The dexamethasone group had reduced conjunctival inflammatory signs without any notable complications.

Clinical Applications of Anterior Segment Optical Coherence Tomography: An Updated Review

Since its introduction, optical coherence tomography (OCT) has revolutionized the field of ophthalmology and has now become an indispensable, noninvasive tool in daily practice. Most ophthalmologists are familiar with its use in the assessment and monitoring of retinal and optic nerve diseases. However, it also has important applications in the assessment of anterior segment structures, including the cornea, conjunctiva, sclera, anterior chamber, and iris, and has the potential to transform the clinical examination of these structures. In this review, we aim to provide a comprehensive overview of the potential clinical utility of anterior segment OCT (AS-OCT) for a wide range of anterior segment pathologies, such as conjunctival neoplasia, pterygium, scleritis, keratoconus, corneal dystrophies, and infectious/noninfectious keratitis. In addition, the clinical applications of AS-OCT (including epithelial mapping) in preoperative planning and postoperative monitoring for corneal and refractive surgeries are discussed.

[Current possibilities for the diagnosis and treatment of pterygium]

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

Pterygium surgery using inferior rotational conjunctival autograft versus conventional conjunctival autograft with sutures - A comparative study

PURPOSE

To compare the outcomes of pterygium surgery by using an inferior rotational autograft and a conventional superior conjunctival autograft.

METHODS

This was a prospective interventional comparative study of 85 eyes of patients who were divided into two groups of 45 and 40. Standard techniques of both procedures were performed by a single surgeon. Astigmatism, recurrence rates, time taken, and other complications were compared.

RESULTS

All the subjects were in the age group 53 ± 7.56 (40-74) years. Demographic data and type of pterygium were comparable in the two groups. In the rotational group, the preoperative astigmatism was - 2.14 ± 1.36 D, which decreased in 1 week to 1.42 ± 1.11 D, in 1 month to - 1.13 ± 0.99 D, in 3 months to 0.91 ± 0.72 D, and in 6 months to 0.81 ± 0.85 D (P < 0.05 each). Preoperative astigmatism in the conventional group was - 2.63 ± 1.47 D, which decreased to - 1.43 ± 1.04 D in 1 week, -1.18 ± 0.85 D in 1 month, -1.07 ± 0.81 D in 3 months, and - 1.01 ± 0.78 D in 6 months (P < 0.05 each). There was no significant difference between the groups in terms of astigmatism at any follow-up visit (P < 0.05). Complications like dellen, graft edema, and superficial vascularization were seen in both groups. The rotational group had one recurrence (2.86%). No recurrence was noted in the conventional group. None of the complication rates was significantly different between the two groups (P < 0.05).

CONCLUSION

Inferior rotational conjunctival autografting is a good technique for management of pterygium. It has a profile similar to that of conventional conjunctival autograft.

Results of Fibrin Glue Applied Over the Corneal Surface Immediately After Pterygium Surgery: A Novel Pain Relief Technique

PURPOSE

The aim of this study was to compare the use of fibrin glue on the corneal epitheliectomy site at the end of pterygium surgery versus conventional eye patch regarding pain levels, need for oral analgesic medications, number of days feeling pain, and awakening due to pain after surgery.

METHODS

Forty-eight eyes of 24 patients with bilateral primary pterygium were included in this prospective, randomized, double-masked controlled trial. Each eye of the same patient was randomized to the intervention or control group. The intervention group received 2 drops of fibrin glue in the epitheliectomy site at the end of surgery and an eye patch, whereas the control group was only received an eye patch. Patients returned on the first and seventh days after surgery. Pain intensity (measured using the visual pain analog scale), need for oral analgesics, the number of days the pain lasted, and quality of sleep were assessed during follow-up visits and compared between groups. Comparison analysis accounted for sex, age, pterygium grading, and comorbidities.

RESULTS

Visual analog pain scale after surgery was significantly lower in eyes receiving fibrin glue (-1.58; 95% confidence interval: -2.84 to -0.32; P = 0.014). In addition, the intervention group presented a 73% lower chance of using oral analgesics (OR: 0.27; 95% confidence interval: 0.07-0.95; P = 0.041). No difference in the awakenings at night was noted ( P = 0.240) nor the mean days of ocular pain in the first week after surgery ( P = 0.474).

CONCLUSIONS

Fibrin glue at the end of pterygium surgery effectively reduces pain and the need for oral analgesics compared with conventional eye patching. This study is the first to describe the results of this strategy.

The role of HPV in the etiopathogenesis of pterygium and the relationship with recurrence

PURPOSE

The primary aim of this study was to determine the prevalence of HPV in pterygium with polymerase chain reaction (PCR) testing and to investigate the relationship with clinicopathological factors. A secondary aim was to evaluate the relationship between HPV and the recurrence of pterygium.

METHODS

The study included 60 patients. PCR analysis was used to determine the presence of HPV. All the patients were followed up in respect of the development of recurrence. Analyses were performed of patient age, pterygium site, specimen and pterygium size, histopathological findings, HPV status, operation technique and postoperative follow-up findings. In the HPV-positive patients, the relationship between HPV subtypes and other factors was evaluated. To determine the risk factors affecting recurrence rates, multivariate Cox regression analysis was applied subsequent to univariate analysis. In the Cox regression model, HPV status, age, sex, specimen size, size and site of pterygium were included among factors that may affect recurrences rates.

RESULTS

Of the total 60 patients, the HPV-PCR test result could not be analysed in 14 because of an insufficient sample. Of the 46 patients with sufficient material for HPV-PCR analysis, the HPV-PCR result was positive in 15 (32.6%). The HPV subtype most often determined was type 16. No statistically significant relationship was determined between HPV positivity and HPV subtype and age or sex. Recurrence was determined in 10% of all the patients. Of the cases determined with recurrence, 66.7% were HPV positive. According to Kaplan-Meier analysis, the recurrence rates in HPV-positive and HPV-negative patients were 26.7% and 6.5%, respectively. A statistically significant difference was found between two groups in terms of recurrence rates (p: 0.046). According to the results of multivariate Cox regression analysis, though not statistically significant, the risk of recurrence was increased 6.18 times in HPV-positive patients with pterygium compared to HPV-negative ones.

CONCLUSION

HPV infection may have a role in the development of pterygium and recurrence, but may not be sufficient alone. HPV probably has a role in the development of pterygium by acting together with several co-factors in the multi-stage process.

The role of anterior segment optical coherence tomography in the evaluation of the pterygium

BACKGROUND

To evaluate the ability of anterior segment optical coherence tomography (AS-OCT) to visualize the anatomic features of the pterygium and its invasion of the corneal layers.

METHODS

Seventy-five eyes of 54 patients diagnosed with pterygium were included. All subjects underwent complete ophthalmologic examinations, including AS-OCT. The limbus-apex distance, vertical height at the limbus, invasion of the Bowman's and stromal layers, and other morphologic structures of the pterygium tissue were analyzed.

RESULTS

The mean age of the patients was 49.67 ± 16.49 (20-85) years. The mean apex-limbus distance was 2548.37 ± 1026.32 (933-4597) μm, and the mean vertical height at the limbus was 4843.89 ± 1374.10 (1740-7784) μm. A space was observed beneath the pterygium tissue in 44 (58.67%) eyes. The mean width and height of this space were 1756.33 ± 560.22 (1009-3095) μm and 231.70 ± 85.88 (109-465) μm, respectively. Invasion of the Bowman's layer was apparent in 74 (98.67%) eyes, and invasion of the stromal layer was detected in 33 (44%) eyes. A hyperreflective layer was observed beneath the epithelial layer at the edge of the pterygium apex in 31 (41.33%) eyes. In 24 (92.31%) of the 26 advanced pterygium cases and 20 (40.82%) of the 49 early pterygium cases, a subpterygium space was found beneath the lesion (p = 0.0001).

CONCLUSION

AS-OCT enables measurement of the actual size and thickness of pterygia, assessment of invasion of the Bowman's and stromal layers of the cornea, and evaluation of the pterygium structure. Over half of the eyes exhibited space beneath the pterygium.

Genomic instability and eye diseases

Background

Genetic information is stored in the bases of double-stranded DNA. However, the integrity of DNA molecules is constantly threatened by various mutagenic agents, including pollutants, ultraviolet light (UV), and medications. To counteract these environmental damages, cells have established multiple mechanisms, such as producing molecules to identify and eliminate damaged DNA, as well as reconstruct the original DNA structures. Failure or insufficiency of these mechanisms can cause genetic instability. However, the role of genome stability in eye diseases is still under-researched, despite extensive study in cancer biology.

Main text

As the eye is directly exposed to the external environment, the genetic materials of ocular cells are constantly under threat. Some of the proteins essential for DNA damage repair, such as pRb, p53, and RAD21, are also key during the ocular disease development. In this review, we discuss five ocular diseases that are associated with genomic instability. Retinoblastoma and pterygium are linked to abnormal cell cycles. Fuchs' corneal endothelial dystrophy and age-related macular degeneration are related to the accumulation of DNA damage caused by oxidative damage and UV. The mutation of the subunit of the cohesin complex during eye development is linked to sclerocornea.

Conclusions

Failure of DNA damage detection or repair leads to increased genomic instability. Deciphering the role of genomic instability in ocular diseases can lead to the development of new treatments and strategies, such as protecting vulnerable cells from risk factors or intensifying damage to unwanted cells.

TFOS Lifestyle Report: Impact of environmental conditions on the ocular surface

Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality, prevalence and possible interactions between risk factors are reviewed. Environmental factors can be (a) climate-related: temperature, humidity, wind speed, altitude, dew point, ultraviolet light, and allergen or (b) outdoor and indoor pollution: gases, particulate matter, and other sources of airborne pollutants. Temperature affects ocular surface homeostasis directly and indirectly, precipitating ocular surface diseases and/or symptoms, including trachoma. Humidity is negatively associated with dry eye disease. There is little data on wind speed and dewpoint. High altitude and ultraviolet light exposure are associated with pterygium, ocular surface degenerations and neoplastic disease. Pollution is associated with dry eye disease and conjunctivitis. Primary Sjögren syndrome is associated with exposure to chemical solvents. Living within a potential zone of active volcanic eruption is associated with eye irritation. Indoor pollution, "sick" building or house can also be associated with eye irritation. Most ocular surface conditions are multifactorial, and several environmental factors may contribute to specific diseases. A systematic review was conducted to answer the following research question: "What are the associations between outdoor environment pollution and signs or symptoms of dry eye disease in humans?" Dry eye disease is associated with air pollution (from NO2) and soil pollution (from chromium), but not from air pollution from CO or PM10. Future research should adequately account for confounders, follow up over time, and report results separately for ocular surface findings, including signs and symptoms.

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

Use of Cryopreserved Amniotic Membrane During Pterygium Excision: Health Economic Analysis

Purpose

To determine the health economic opportunity cost or gain associated with performing pterygium excision surgery using the TissueTuck technique with cryopreserved amniotic membrane (AM) instead of conjunctival autograft (CAU).

Methods

We performed a literature review to determine the average surgical duration of pterygium surgery using CAU with fibrin glue or sutures to calculate the average time saved with the TissueTuck technique. Such time savings was then used to determine the opportunity revenue gain per national average Medicare reimbursement if adjusted to the average surgical duration of cataract surgery.

Results

The time savings achieved using the TissueTuck technique over CAU with fibrin glue is 8.9 min per procedure, which can be applied to additional MSICS or phacoemulsification procedures to generate an opportunity revenue gain of $1167 or $762 per 2022 National Average Medicare reimbursement, respectively. After subtracting the current list cost of AmnioGraft (ie, $645), the opportunity gain is $522 or $117 if the time saving is applied to the above procedures, respectively. Alternatively, the time savings achieved by using the TissueTuck technique over CAU with sutures is 23.4 min per procedure, which can be applied to additional MSICS or phacoemulsification procedures to generate an opportunity revenue gain of $3068 and $2004 per TissueTuck procedure or $2423 or $1359 when accounting for the list cost of AmnioGraft, respectively.

Conclusion

The TissueTuck surgical technique using cryopreserved AM for pterygium takes less time, has lower recurrence rates, and provides an opportunity gain compared to pterygium excision with CAU.

Epidemiologic characteristics and the change of surgical methods of pterygium and pseudopterygium from 2013 to 2019 in China: A retrospective analysis

Introduction

Pterygium is a common multifactorial external eye disease, which causes various ocular symptoms and negatively affects appearance. The aim of this study was to analyze the epidemiological characteristics and the change of surgical methods of pterygium and pseudopterygium in China from 2013 to 2019.

Materials and methods

This study was a hospital-based nationwide retrospective study to estimate the epidemiologic characteristics and the change of surgical methods of pterygium and pseudopteygium in China from 2013 to 2019. The data was extracted from the Hospital Quality Monitoring System (HQMS) database. The diagnosis was based on the tenth revision of the International Classification of Diseases (ICD-10) code.

Results

Our study included 1,007,800 pterygium and 2,681 pseudopteygium inpatients. From 2013 to 2019, the proportion of pterygium and pseudopterygium patients who underwent surgery, among all ophthalmology inpatients, increased from 3.3% in 2013 to 7.84% in 2019. The male-female ratio of surgically treated pterygium and pseudopterygium is 1:1.8 and 1.6:1 respectively. Among all age groups, the hospitalized pterygium patients who received surgery were mainly 60-69 years old, accounting for 36.53%. The pseudopterygium patients who received surgery were mostly 50-59 years old, accounting for 24.02%. Among the 31 provinces of mainland China, Yunnan Province has the highest proportion of pterygium patients treated surgically (6.40%), while Shanghai has the highest proportion of pseudopterygium patients treated surgically (12.98%). The most common occupation of participants in the study was farmer, accounting for 47.62% and 28.53%, respectively. During the study period, the application of autologous stem cell transplantation increased year by year, and became the first choice for pterygium and pseudopterygium surgery.

Discussion

This study was the first to describe the epidemiological characteristics and surgical methods of hospitalized pterygium and pseudopterygium patients in China. This study provides important information for better diagnosis, treatment and prevention of pterygium and pseudopterygium.

TFOS lifestyle: Impact of societal challenges on the ocular surface

Societal factors associated with ocular surface diseases were mapped using a framework to characterize the relationship between the individual, their health and environment. The impact of the COVID-19 pandemic and mitigating factors on ocular surface diseases were considered in a systematic review. Age and sex effects were generally well-characterized for inflammatory, infectious, autoimmune and trauma-related conditions. Sex and gender, through biological, socio-economic, and cultural factors impact the prevalence and severity of disease, access to, and use of, care. Genetic factors, race, smoking and co-morbidities are generally well characterized, with interdependencies with geographical, employment and socioeconomic factors. Living and working conditions include employment, education, water and sanitation, poverty and socioeconomic class. Employment type and hobbies are associated with eye trauma and burns. Regional, global socio-economic, cultural and environmental conditions, include remoteness, geography, seasonality, availability of and access to services. Violence associated with war, acid attacks and domestic violence are associated with traumatic injuries. The impacts of conflict, pandemic and climate are exacerbated by decreased food security, access to health services and workers. Digital technology can impact diseases through physical and mental health effects and access to health information and services. The COVID-19 pandemic and related mitigating strategies are mostly associated with an increased risk of developing new or worsening existing ocular surface diseases. Societal factors impact the type and severity of ocular surface diseases, although there is considerable interdependence between factors. The overlay of the digital environment, natural disasters, conflict and the pandemic have modified access to services in some regions.

Uncovering the role of transient receptor potential channels in pterygium: a machine learning approach

OBJECTIVES

We aimed at identifying the role of transient receptor potential (TRP) channels in pterygium.

METHODS

Based on microarray data GSE83627 and GSE2513, differentially expressed genes (DEGs) were screened and 20 hub genes were selected. After gene correlation analysis, 5 TRP-related genes were obtained and functional analyses of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed. Multifactor regulatory network including mRNA, microRNAs (miRNAs) and transcription factors (TFs) was constructed. The 5 gene TRP signature for pterygium was validated by multiple machine learning (ML) programs including support vector classifiers (SVC), random forest (RF), and k-nearest neighbors (KNN). Additionally, we outlined the immune microenvironment and analyzed the candidate drugs. Finally, in vitro experiments were performed using human conjunctival epithelial cells (CjECs) to confirm the bioinformatics results.

RESULTS

Five TRP-related genes (MCOLN1, MCOLN3, TRPM3, TRPM6, and TRPM8) were validated by ML algorithms. Functional analyses revealed the participation of lysosome and TRP-regulated inflammatory pathways. A comprehensive immune infiltration landscape and TFs-miRNAs-mRNAs network was studied, which indicated several therapeutic targets (LEF1 and hsa-miR-455-3p). Through correlation analysis, MCOLN3 was proposed as the most promising immune-related biomarker. In vitro experiments further verified the reliability of our in silico results and demonstrated that the 5 TRP-related genes could influence the proliferation and proinflammatory signaling in conjunctival tissue contributing to the pathogenesis of pterygium.

CONCLUSIONS

Our study suggested that TRP channels played an essential role in the pathogenesis of pterygium. The identified pivotal biomarkers (especially MCOLN3) and pathways provide novel directions for future mechanistic and therapeutic studies for pterygium.

The effects of exposure to solar radiation on human health

This assessment by the Environmental Effects Assessment Panel (EEAP) of the Montreal Protocol under the United Nations Environment Programme (UNEP) evaluates the effects of ultraviolet (UV) radiation on human health within the context of the Montreal Protocol and its Amendments. We assess work published since our last comprehensive assessment in 2018. Over the last four years gains have been made in knowledge of the links between sun exposure and health outcomes, mechanisms, and estimates of disease burden, including economic impacts. Of particular note, there is new information about the way in which exposure to UV radiation modulates the immune system, causing both harms and benefits for health. The burden of skin cancer remains high, with many lives lost to melanoma and many more people treated for keratinocyte cancer, but it has been estimated that the Montreal Protocol will prevent 11 million cases of melanoma and 432 million cases of keratinocyte cancer that would otherwise have occurred in the United States in people born between 1890 and 2100. While the incidence of skin cancer continues to rise, rates have stabilised in younger populations in some countries. Mortality has also plateaued, partly due to the use of systemic therapies for advanced disease. However, these therapies are very expensive, contributing to the extremely high economic burden of skin cancer, and emphasising the importance and comparative cost-effectiveness of prevention. Photodermatoses, inflammatory skin conditions induced by exposure to UV radiation, can have a marked detrimental impact on the quality of life of sufferers. More information is emerging about their potential link with commonly used drugs, particularly anti-hypertensives. The eyes are also harmed by over-exposure to UV radiation. The incidence of cataract and pterygium is continuing to rise, and there is now evidence of a link between intraocular melanoma and sun exposure. It has been estimated that the Montreal Protocol will prevent 63 million cases of cataract that would otherwise have occurred in the United States in people born between 1890 and 2100. Despite the clearly established harms, exposure to UV radiation also has benefits for human health. While the best recognised benefit is production of vitamin D, beneficial effects mediated by factors other than vitamin D are emerging. For both sun exposure and vitamin D, there is increasingly convincing evidence of a positive role in diseases related to immune function, including both autoimmune diseases and infection. With its influence on the intensity of UV radiation and global warming, the Montreal Protocol has, and will have, both direct and indirect effects on human health, potentially changing the balance of the risks and benefits of spending time outdoors.

Double Flip Technique for Graft Transfer in Autograft Pterygium Surgery

A 50-year-old man with recurrent pterygium and a 46-year-old woman with primary pterygium underwent surgery using a novel autograft transfer technique that facilitates autograft suturing and ensures correct graft orientation. After removing the pterygium, three edges of the autograft were cut. The autograft was flipped first over the uncut edge and secured to the superior margin of the recipient bed with two sutures. Afterward, the fourth side of the graft was cut and the second flip was done over the sutured edge. Thus, the autograft was in correct surface and side orientation and was sutured to the recipient bed. This simple technique provides both easy transfer and correct orientation of the graft in autograft pterygium surgery.

Autologous fibrin glue versus sutures for conjunctival autograft in primary pterygium: a randomized clinical trial

PURPOSE

To describe and compare the autologous fibrin glue and traditional sutures for conjunctival graft attachment in patients undergoing primary pterygium excision surgery.

METHOD

A randomized clinical trial included patients who underwent pterygium surgery with conjunctival autologous graft (CAG). Using randomization, a single-trained surgeon performed graft fixation with autologous glue or sutures. The glue was prepared immediately before the surgery, using the patient's blood components. After centrifugation, the plasma was collected and enhanced with calcium gluconate. Postoperative assessments were performed on Days 1, 7, 21, 30 and 180. The study evaluated postoperative edema and pain and complications. The mean surgical time was compared. Recurrence of the pterygium was assessed 6 months postoperatively.

RESULTS

The study evaluated 61 eyes. Thirty-three eyes underwent pterygium surgery using the glue technique, and 28 underwent the traditional suture technique. Fifty-one patients (83.60%) had successful graft adhered to at the end of follow-up. Ten patients (10/33) lost their graft in the glue group, and only 69.70% maintained graft presence in the fourth week versus 100% of the patients in the suture group (p = 0.001). Pain scores were lower in the glue group, and clinical edema was significantly higher. There was no significant difference in graft retraction or the presence of granuloma, necrosis or postoperative infection.

CONCLUSION

Autologous fibrin glue is an affordable option for CAG fixation in particular contexts where commercial fibrin glue is unavailable, and it could offer advantages compared to sutures. A higher graft loss rate was observed and might be related to topical anesthesia, and improvements to the technique are needed.

CLINICALTRIALS

gov Identifier: NCT04151017. https://clinicaltrials.gov/ct2/show/NCT04151017?term=20170467&draw=1&rank=1 .

Ophthalmology foundation Ophthalmic Surgical Competency Assessment Rubric (OSCAR) for pterygium surgery

Background

Pterygium surgery is a procedure commonly performed by ophthalmologists. Valid, objective methods are needed to assess competence in this procedure.

Methods

A panel of 5 specialists consisting of members from different regions of the world including Pakistan, United States, Iran, Mongolia and Peru was formed to create a rubric for assessment of pterygium surgery by residents. The assessment rubric was developed using the standard template of Ophthalmology Surgical Competency Assessment Rubrics (OSCARs) previously published. The rubric was designed using a modified Dreyfus model of skill acquisition on a four-point behavioral scale.

Results

The rubric consisted of 14 essential steps in pterygium surgery and 5 global indices. The content and face validity of the rubric was refined by repeatedly reviewing the rubric on Googledocs and considering critiques by a panel of 10 cornea specialists from around the world. Each step was divided into four levels, from novice to competent. The skill required for each level was described specifically to help decrease rater subjectivity.

Conclusions

The OSCAR for pterygium surgery has face-validity and can be used effectively for both teaching and assessing ophthalmology residents in training programs across the world.

Deep learning algorithms for automatic detection of pterygium using anterior segment photographs from slit-lamp and hand-held cameras

BACKGROUND/AIMS

To evaluate the performances of deep learning (DL) algorithms for detection of presence and extent pterygium, based on colour anterior segment photographs (ASPs) taken from slit-lamp and hand-held cameras.

METHODS

Referable pterygium was defined as having extension towards the cornea from the limbus of >2.50 mm or base width at the limbus of >5.00 mm. 2503 images from the Singapore Epidemiology of Eye Diseases (SEED) study were used as the development set. Algorithms were validated on an internal set from the SEED cohort (629 images (55.3% pterygium, 8.4% referable pterygium)), and tested on two external clinic-based sets (set 1 with 2610 images (2.8% pterygium, 0.7% referable pterygium, from slit-lamp ASP); and set 2 with 3701 images, 2.5% pterygium, 0.9% referable pterygium, from hand-held ASP).

RESULTS

The algorithm's area under the receiver operating characteristic curve (AUROC) for detection of any pterygium was 99.5%(sensitivity=98.6%; specificity=99.0%) in internal test set, 99.1% (sensitivity=95.9%, specificity=98.5%) in external test set 1 and 99.7% (sensitivity=100.0%; specificity=88.3%) in external test set 2. For referable pterygium, the algorithm's AUROC was 98.5% (sensitivity=94.0%; specificity=95.3%) in internal test set, 99.7% (sensitivity=87.2%; specificity=99.4%) in external set 1 and 99.0% (sensitivity=94.3%; specificity=98.0%) in external set 2.

CONCLUSION

DL algorithms based on ASPs can detect presence of and referable-level pterygium with optimal sensitivity and specificity. These algorithms, particularly if used with a handheld camera, may potentially be used as a simple screening tool for detection of referable pterygium. Further validation in community setting is warranted.

SYNOPSIS/PRECIS

DL algorithms based on ASPs can detect presence of and referable-level pterygium optimally, and may be used as a simple screening tool for the detection of referable pterygium in community screenings.

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.

Risk Factors Associated With Pterygium Reoperation in the IRIS Registry

This cohort study used data from the IRIS Registry to assess the risk factors associated with pterygium reoperation.

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.

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.

Autologous simple conjunctival epithelial transplantation for primary pterygium

PURPOSE

To evaluate the feasibility of a new method of conjunctival transplantation to achieve recovery of the normal conjunctival epithelium over the bare sclera after pterygium excision and prevent its recurrence.

METHODS

After excision of the primary pterygium, we performed simple conjunctival epithelial transplantation (SCET) in which we glued an amniotic membrane patch pre-loaded with tiny autologous conjunctival tissue fragments over the scleral defect. Slit-lamp evaluation was performed at 2 and 7-10 days, and then at 1, 3, 6, and 12 months after surgery, together with confocal microscopy at 3, 6, and 12 months.

RESULTS

Surgical excision and SCET for nasal primary pterygium were performed in 6 eyes (6 patients). No graft detachment occurred. An inflammatory granuloma was excised without sequelae in one patient 2 months after surgery. No signs of recurrence or sight-threatening complications were recorded at 12 months, and in vivo confocal microscopy showed progressive expansion of the conjunctival cell population and formation of a clear corneal-conjunctival transition.

CONCLUSIONS

SCET takes advantage of the ability of the amniotic membrane and conjunctival cells to renew. Outcomes after SCET are comparable to conventional conjunctival flap surgery and can be achieved in less surgical time and with less donor tissue to be removed.

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. 

Computer-Assisted Pterygium Screening System: A Review

Pterygium is an eye condition that causes the fibrovascular tissues to grow towards the corneal region. At the early stage, it is not a harmful condition, except for slight discomfort for the patients. However, it will start to affect the eyesight of the patient once the tissues encroach towards the corneal region, with a more serious impact if it has grown into the pupil region. Therefore, this condition needs to be identified as early as possible to halt its growth, with the use of simple eye drops and sunglasses. One of the associated risk factors for this condition is a low educational level, which explains the reason that the majority of the patients are not aware of this condition. Hence, it is important to develop an automated pterygium screening system based on simple imaging modalities such as a mobile phone camera so that it can be assessed by many people. During the early stage of automated pterygium screening system development, conventional machine learning techniques such as support vector machines and artificial neural networks are the de facto algorithms to detect the presence of pterygium tissues. However, with the arrival of the deep learning era, coupled with the availability of large training data, deep learning networks have replaced the conventional networks in screening for the pterygium condition. The deep learning networks have been successfully implemented for three major purposes, which are to classify an image regarding whether there is the presence of pterygium tissues or not, to localize the lesion tissues through object detection methodology, and to semantically segment the lesion tissues at the pixel level. This review paper summarizes the type, severity, risk factors, and existing state-of-the-art technology in automated pterygium screening systems. A few available datasets are also discussed in this paper for both classification and segmentation tasks. In conclusion, a computer-assisted pterygium screening system will benefit many people all over the world, especially in alerting them to the possibility of having this condition so that preventive actions can be advised at an early stage.

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.

Transcriptomics and network analysis highlight potential pathways in the pathogenesis of pterygium

Pterygium is a common ocular surface condition frequently associated with irritative symptoms. The precise identity of its critical triggers as well as the hierarchical relationship between all the elements involved in the pathogenesis of this disease are not yet elucidated. Meta-analysis of gene expression studies represents a novel strategy capable of identifying key pathogenic mediators and therapeutic targets in complex diseases. Samples from nine patients were collected during surgery after photo documentation and clinical characterization of pterygia. Gene expression experiments were performed using Human Clariom D Assay gene chip. Differential gene expression analysis between active and atrophic pterygia was performed using limma package after adjusting variables by age. In addition, a meta-analysis was performed including recent gene expression studies available at the Gene Expression Omnibus public repository. Two databases including samples from adults with pterygium and controls fulfilled our inclusion criteria. Meta-analysis was performed using the Rank Production algorithm of the RankProd package. Gene set analysis was performed using ClueGO and the transcription factor regulatory network prediction was performed using appropriate bioinformatics tools. Finally, miRNA-mRNA regulatory network was reconstructed using up-regulated genes identified in the gene set analysis from the meta-analysis and their interacting miRNAs from the Brazilian cohort expression data. The meta-analysis identified 154 up-regulated and 58 down-regulated genes. A gene set analysis with the top up-regulated genes evidenced an overrepresentation of pathways associated with remodeling of extracellular matrix. Other pathways represented in the network included formation of cornified envelopes and unsaturated fatty acid metabolic processes. The miRNA-mRNA target prediction network, also reconstructed based on the set of up-regulated genes presented in the gene ontology and biological pathways network, showed that 17 target genes were negatively correlated with their interacting miRNAs from the Brazilian cohort expression data. Once again, the main identified cluster involved extracellular matrix remodeling mechanisms, while the second cluster involved formation of cornified envelope, establishment of skin barrier and unsaturated fatty acid metabolic process. Differential expression comparing active pterygium with atrophic pterygium using data generated from the Brazilian cohort identified differentially expressed genes between the two forms of presentation of this condition. Our results reveal differentially expressed genes not only in pterygium, but also in active pterygium when compared to the atrophic ones. New insights in relation to pterygium's pathophysiology are suggested.

Comparison of pterygium recurrence with and without using postsurgical topical cyclosporin a 0.05%: A randomized clinical trial

Purpose:

To evaluate the efficacy of 3-month administration of topical cyclosporin A (CsA) 0.05% on postoperative recurrence after pterygium surgery.

Methods:

In this randomized clinical trial, 78 patients undergoing pterygium surgery (using the rotational conjunctival flap technique with mitomycin C [MMC]) were enrolled and randomly allocated into the control (n = 39) and case (CsA) (n = 39) groups in a single-blind method. The patients were examined on postoperative days 1, 3, and 7 and months 1, 3, and 6, and their best-corrected visual acuity, intraocular pressure, clinical inflammation, postoperative complications, and recurrence were compared.

Results:

The mean age of patients was 53.22 ± 9.99 years; most (57.7%) of them were men. The two groups were not different in terms of demographics, pterygium size, or pterygium grade. The clinical inflammation at the first and third postoperative months was not different between the groups (P = 0.108 and 0.780, respectively). No serious complications were detected; complication rates were not different between the groups (P = 0.99). The recurrence rate was 5.1% in the case group and 7.7%% in the control group (P = 0.99).

Conclusion:

The present study showed no priority for 3-month administration of CsA 0.05% drops on postoperative outcomes, including prevention of pterygium recurrence, complications, and inflammation after the rotational conjunctival autograft technique with MMC.

Optimizing the ocular surface prior to cataract surgery

PURPOSE OF REVIEW

Ocular surface disease can significantly impact the outcomes of cataract surgery. Recent studies have examined the efficacy of several new dry eye disease (DED) therapies, the extent to which epithelial debridement affects keratometric measurements in epithelial basement membrane dystrophy (EBMD) and Salzmann nodular degeneration (SND), and the predictability of refractive error following combined pterygium and cataract removal. This review aims to incorporate these newer studies in updating and further emphasizing the need for careful management and optimization of common ocular surface conditions prior to cataract surgery.

RECENT FINDINGS

Common ocular surface conditions such as DED, EBMD, SND, and pterygium can cause significant irregular astigmatism and higher-order aberrations. Their resolution can substantially alter biometry measurements in preparation for cataract surgery, affecting the final visual outcome. Newer therapies for DED, such as topical lifitegrast and thermal pulsation treatment, can aid in this optimization process. If superficial keratectomy or excisions of lesions on the ocular surface are performed, sufficient healing time is needed to allow the ocular surface to reach stability prior to biometry measurements.

SUMMARY

Ocular surface optimization is key to successful cataract surgery planning and reaching desired outcomes.

Impact of fibrin glue versus suture closure on double-headed pterygia in Asian eyes - a 7-year study in a tertiary institution

BACKGROUND

To compare the recurrence rate and outcomes of double-headed pterygia using fibrin glue versus suture closure of conjunctival autograft.

METHODS

All patients with double-headed pterygia who underwent pterygia excision with conjunctival autograft from January 2012 to January 2019 in the National University Hospital of Singapore were included. Patients were divided into 2 groups depending on whether fibrin glue or sutures were used to secure the conjunctival autograft in place. All patients had a minimum of 6 months follow-up.

RESULTS

A total (26 patients) of 22 eyes had fibrin glue, while eight eyes underwent suture closure of their conjunctival autograft. Fibrin glue group had 4.5% recurrence rate, while suture group had 37.5% recurrence rate (p = .021). There is statistically significant improvement for overall visual acuity (p = .009) and cylinder (p = .002). There is also statistically significant improvement for visual acuity in the glue group (p = .026), but not in the suture group. Fibrin glue group had a shorter operation duration time compared to suture group (p < .001).There were no cases of graft dislocation, contraction or limbal stem cell deficiency.

CONCLUSIONS

Low recurrence rates and good postoperative visual outcomes can be achieved with the split conjunctival autograft technique. Our study suggests that fibrin glue has an additional benefit over the use of sutures in the management of these complex cases.

Pterygium Recurrence Rates in the Hispanic Population in the Northeastern United States

Purpose:

To determine the rate and factors affecting pterygium recurrence in the Hispanic population of the Northeastern United States, based on patient demographic information.

Methods:

In this retrospective cross-sectional study, data were collected on ethnically Hispanic patients from 2013 to 2018 who had primary single-headed pterygia excision and conjunctival autograft, with the minimum of 4-month follow-up time. This study was conducted in an academic institution in the Northeastern United States, with all patients being from the surrounding community.

Results:

In 168 Hispanic patients with confirmed primary single-headed pterygium, most pterygia occurred nasally (161/168). The average age of presentation was 46.3 ± 12.0 years (range, 23–77 years). There were 22 recurrences (13.1%), occurring at an average of 3.0 ± 1.6 months (1–8 months). This cohort demonstrated a unimodal recurrence distribution. Age is significantly inversely correlated with the incidence of recurrence (r = −0.219, P = 0.004), but not with the size of the recurrent pterygia (r = −0.112, P = 0.621). There was no significant difference between recurrence based on gender (P = 0.265), location (P = 0.824), or laterality (right or left eye) (P = 0.213). Mean corrected visual acuity improved from 20/40 to 20/32 after pterygium excision (P < 0.001). Cox regression analysis for age groups shows the risk of recurrence for patients aged 20–29 is 11.4-time that of patients aged 50 and above (P < 0.001).

Conclusions:

Recurrence occurred unimodally at around 3 months postoperatively. Younger patients are significantly more susceptible to recurrence. Future studies may seek to determine the incidence of pterygia and their recurrence patterns in relation to occupations and sun exposure time in a geographic area.

Does pterygium morphology affect corneal astigmatism?

Purpose:

The purpose of this study was to evaluate the correlation between corneal astigmatism and the morphology of pterygium with anterior segment optic coherence tomography (AS-OCT).

Material and Methods:

The size of pterygium (horizontal length, vertical width) was measured manually; pterygium area and percentage extension of the pterygium onto the cornea were calculated. Anterior and posterior corneal astigmatism, Sim K, K1, K2 were measured using a dual Scheimpflug analyzer. Morphological patterns of the pterygium analyzed with AS-OCT were determined according to the extension of the pterygium apex below the corneal epithelium. Two tomographic patterns were identified: continuous and nodular. Correlation between anterior corneal astigmatism and pterygium size, percentage extension of the pterygium, and morphological pattern of the pterygium was analyzed.

Results:

The mean ages of the 47 patients were 49.4 ± 16.6 (22–80) years. Mean horizontal pterygium length, vertical width, pterygium area, and percentage extension of the pterygium were 2.8 ± 1.2 mm, 4.8 ± 1.6 mm, 7.42 ± 5.6 mm² and 24.5 ± 10.4%, respectively. Mean anterior corneal astigmatism was 2.3 ± 2.3 D and simulated keratometry was 43.4 ± 2.02 D. In terms of the morphological pattern of the pterygium, 24 eyes had continuous, 23 eyes had a nodular pattern and the median (interquartile range) anterior corneal astigmatism was 1.87 (1.01–3.80) and 1.22 D (0.58–2.35), respectively (p = 0.102). Other topographic and pterygium size parameters were similar between groups. Analyzing the correlations in groups separately, a positive moderate statistically significant correlation was present between vertical width, percentage extension, pterygium area, and anterior corneal astigmatism in both continuous and nodular groups.

Conclusions:

Although not statistically significant, anterior corneal astigmatism was higher in continuous group. Using AS-OCT to standardize the morphology of pterygium could provide additional clinical information.

Pterygium-The Good, the Bad, and the Ugly

Pterygium is a multifaceted pathology that displays apparent conflicting characteristics: benign (e.g., self-limiting and superficial), bad (e.g., proliferative and potentially recurrent) and ugly (e.g., signs of preneoplastic transformation). The natural successive question is: why are we lacking reports showing that pterygium lesions become life-threatening through metastasis, especially since pterygium has considerable similarities with UV-related malignancies on the molecular level? In this review, we consider how our pathophysiological understanding of the benign pterygium pathology overlaps with ocular surface squamous neoplasia and skin cancer. The three UV-related disorders share the same initial insult (i.e., UV radiation) and responsive repair mechanisms to the ensuing (in)direct DNA damage. Their downstream apoptotic regulators and other cellular adaptations are remarkably alike. However, a complicating factor in understanding the fine line between the self-limiting nature of pterygium and the malignant transformation in other UV-related diseases is the prominent ambiguity in the pathological evaluation of pterygium biopsies. Features of preneoplastic transformation (i.e., dysplasia) are used to define normal cellular reactions (i.e., atypia and metaplasia) and vice versa. A uniform grading system could help in unraveling the true nature of this ancient disease and potentially help in identifying the earliest intervention point possible regarding the cellular switch that drives a cell’s fate towards cancer.

Pterygium: an update on pathophysiology, clinical features, and management

Pterygium is a relatively common ocular surface disease. The clinical aspects and the treatment options have been studied since many years ago, but many uncertainties still exist. The core pathologic pathway and the role of heredity in the development of pterygium are still attractive fields for the researchers. The role of pterygium in corneal irregularities, in addition to the refractive properties of pterygium removal, has been increasingly recognized through numerous studies. The association between pterygium and ocular surface neoplasia is challenging the traditional beliefs regarding the safe profile of the disease. The need for a comprehensive clinical classification system has encouraged homogenization of trials and prediction of the recurrence rate of the pterygium following surgical removal. Evolving surgical methods have been associated with some complications, whose diagnosis and management are necessary for ophthalmic surgeons. According to the review, the main risk factor of pterygium progression remains to be the ultraviolet exposure. A major part of the clinical evaluation should consist of differentiating between typical and atypical pterygia, where the latter may be associated with the risk of ocular surface neoplasia. The effect of pterygium on astigmatism and the aberrations of the cornea may evoke the need for an early removal with a purpose of reducing secondary refractive error. Among the surgical methods, conjunctival or conjunctival-limbal autografting seems to be the first choice for ophthalmic surgeons because the recurrence rate following the procedure has been reported to be lower, compared with other procedures. The use of adjuvant options is supported in the literature, where intraoperative and postoperative mitomycin C has been the adjuvant treatment of choice. The efficacy and safety of anti–vascular endothelial growth factor agents and cyclosporine have been postulated; however, their exact role in the treatment of the pterygium requires further studies.

Characteristics and recurrence of pterygium in Saudi Arabia: a single center study with a long follow-up

Background

This study described the clinical features of patients with pterygium and analyzed the recurrence rate of conjunctival autografting alone, conjunctival autografting combined with intraoperative mitomycin C, and amniotic membrane grafting.

Methods

A retrospective cohort study of primary pterygium was conducted between January 2017 and February 2020. Factors associated with pterygium severity and recurrence were analyzed by univariate analysis and logistic regression models.

Results

The study included 292 patients with an average age of 53.3 ± 14.1 years, while the number of operated cases was 94. Pterygia involving the cornea were observed in 55 % of the cases. The overall rate of recurrence for the three procedures was 17 %. The average time of recurrence was 14.2 ± 11.9 months, with 37 % of the recurrences occurring after the first year. The only factor associated with a significant risk of recurrence was dry eye disease in both univariate (p = 0.021) and multivariate analysis (p = 0.026). The recurrence rates following conjunctival autografting with and without mitomycin C were 15.6 and 15.8 %, respectively. The recurrence rate following the amniotic membrane graft was  twofold (OR= 2.02)  (27 %) that following the conjunctival autograft (15.8 %).

Conclusions

The only factor associated with the recurrence of pterygium was dry eye disease. More than one-third of recurrences developed after the first year, which stresses the importance of a long follow-up. The recurrence rate in our study following conjunctival graft was slightly higher compared to the literature mainly due to differences in study areas, populations, and follow-up periods.

Comparison of vitamin D levels between patients with pterygium and healthy subjects

PURPOSE

The purpose of this study was to compare vitamin D (VD) deficiency frequency among patients with pterygium to that of healthy subjects and to investigate the VD deficiency among patients with pterygium.

METHODS

One-hundred eight pterygium patients and 94 healthy subjects were included in the study. Blood samples were collected from groups during the same time interval and the samples were saved. Serum 25-hydroxyvitamin D (25(OH)D) and parathormone (PTH) levels were measured and analyzed.

RESULTS

The pterygium group consisted of 57 female and 51 male patients, while the control group consisted of 47 female and 47 male patients. The mean age, sex and mean BMI were similar in the two groups (p > 0.05). The percentage of time that individuals spent outdoors was higher in the pterygium group (p = 0.02). The percentage of VD deficiency was 83.3% in the pterygium group and 61.7% in the control group (p = 0.001). There was a positive correlation between VD and time spent outdoors (p < 0.05).

CONCLUSIONS

VD deficiency can play a role in pterygium etiopathogenesis. Wide population-based studies in different regions are needed to evaluate this result.

[Pterygium: pathogenesis, diagnosis and treatment]

The pterygium is a frequent ultraviolet (UV) light-induced focal fibrovascular proliferation of the conjunctival tissue onto the cornea. Surgical excision should be performed in the case of reduced visual acuity, progressive astigmatism, impending invasion of the optical axis and ocular surface complaints. The main factors in preventing recurrence include optimal surgical treatment by an excision combined with a free conjunctival autograft, consistent postoperative treatment with preservative-free artificial tears and topical steroids as well as long-term UV protection.

Cost-effectiveness analysis : fibrin glue versus sutures for conjonctival fixation during pterygion surgery

OBJECTIVE

Pterygium surgery requires the removal of pterygium tissue and repair of the conjunctiva with either sutures or fibrin glue. The literature suggests that the cost of fibrin glue could be compensated by reducing procedure time and be more cost-effective. However, to our knowledge, no formal studies have examined this hypothesis.

METHOD

Retrospective chart review of patients who received pterygium surgery with only sutures between January 2008 and January 2010, and those whose surgeons used fibrin glue with or without sutures, between April 2017 and November 2018. Equipment cost, operating room (OR) maintenance, and surgeon's remuneration were compared between the groups.

RESULTS

A total of 164 eyes were included. Three different procedure methods were noted: use of sutures only, combination of sutures and fibrin glue, or application of fibrin glue alone. The equipment cost was $97, $169.50, and $152.10 for the suture group, dual method, and fibrin-only method. Average procedure time was 35.8 minutes for the sutures-only group, 21.1 minutes for the dual method, and 25.6 minutes for the method using only glue. OR maintenance cost was $51.20 CAD per minute. The total cost for the method using only sutures was $2528.90, whereas the average cost for the protocol using only fibrin glue was $2063.

CONCLUSION

Although using fibrin glue for conjunctival graft adhesion increases the equipment cost, it significantly decreases procedure time, which allows a reduction of the total surgery cost. Therefore, fibrin glue is a more cost-effective approach than sutures alone.

Changes of Corneal Biomechanical Properties upon Exclusive Ytt-/Sr-90 Irradiation of Pterygium

BACKGROUND

It is known that pterygia above a certain size cause astigmatism and other aberrations of the human cornea and thus impair the quality of vision. Exclusive Sr-/Ytt-90 beta irradiation is a highly effective treatment for primary pterygia. The aim of this retrospective study is to determine the extent to which higher order corneal aberrations are affected by this treatment.

METHODS

Evaluation of corneal topographies and wavefront aberration data of 20 primary pterygia patients generated before and at different points in time in the first year after irradiation. Additionally, the size of the pterygium was measured.

RESULTS

The study showed a significant increase in coma and triple leaf aberrations in pterygia with a horizontal length of 2 mm and more. It was also found that a pterygium size greater than 2 mm significantly induces astigmatism. Both phenomena reduce visual quality. In none of the patients could a pterygium recurrence be detected after irradiation.

CONCLUSIONS

If the pterygium size is less than 2 mm, early exclusive Sr/Ytt-90 beta irradiation can be recommended. If the size is more than 2 mm, a pterygium excision 6 months after beta irradiation can be discussed.

Prevalence of Pterygium and Associated Risk Factors in the High-Altitude Area of Ta'if City, Saudi Arabia

Background

Pterygium is an important public health problem. The prevalence rates of this disease varies widely from 1.2% to 23.4%.

Aim

To determine the prevalence rates and the associated risk factors of pterygium in the high-altitude area - Ta’if city, Saudi Arabia.

Material and method

A cross-sectional study was carried out from September 2018 till September 2019 at the ophthalmology outpatient clinics of King Abdul-Aziz Specialist Hospital, Ta’if area.

Results

Prevalence rate of pterygium in the high-altitude area, Ta’if city, Saudi Arabia was 2.4%. It is significantly higher in older patients belonging to the age group of more than 40 years. As for gender, it was significantly higher in male patients compared to females (2.6% vs. 1.9%). Pterygium prevalence was significantly higher among patients with outdoor occupations compared to indoor occupations (2.9% vs. 2.1%), and among patients with sunlight exposure during daily activities for more than 5 hours (2.6% vs. 2%) (p =< 0.05).

Conclusion

The overall incidence of pterygium in Al-Ta’if area, Saudi Arabia, was 2.4% but still lower than overall worldwide incidence (10.2%). There was an increased incidence of pterygium with age, high-altitude areas, rural areas, outdoor occupations, which is directly proportional to dose of sunlight exposure. Furthermore, smoking might be reported as a protective factor against pterygium.

A randomized clinical trial of freeze-dried amniotic membrane transplantation and conjunctival-limbal graft for pterygium excision and evaluation of conjunctival inflammation marker in tears

BACKGROUND Minimizing inflammation on the ocular surface after pterygium surgery is essential to prevent recurrence. Currently, limited data are available for the comparison between freeze-dried amniotic membrane (FD-AM) and conjunctival–limbal graft (CLG). Therefore, this study aimed to assess conjunctival inflammation and the interleukin (IL)-6 levels in tears after pterygium excision between both techniques. METHODS This prospective, single-blinded, randomized clinical trial included 26 eyes of 26 patients with primary or recurrent pterygium and who were indicated for pterygium surgery at Cipto Mangunkusumo Hospital, Indonesia from October 2017 until February 2018. The patients were scheduled for pterygium excision with FD-AM or CLG based on block randomization. Conjunctival inflammation and the level of IL-6 in tears were measured on day-7 and -28 after surgery. RESULTS The 26 eyes (13 in each group) were subjected to a complete 1-month follow-up period. Day-7 after the surgery, severe inflammation occurred in 4/13 (31%) eyes having FD-AM and 8/13 eyes (62%) having CLG (p = 0.59). The IL-6 tear level increased similarly in FD-AM (22.85 pg/ml) and CLG (23.51 pg/ml) in (p = 0.78). No severe adverse events occurred. CONCLUSIONS Pterygium excision using FD-AM yield a milder inflammation than CLG on day-7 and -28 after surgery. The tear IL-6 levels similarly increased on day-7.

Handing it to pterygium: Explaining pterygium laterality

PURPOSE

To evaluate any correlation between pterygium laterality and patient handedness.

METHODS

Our study represents a retrospective observational study of a series of consecutive pterygium patients recruited from two centres. Each patient was assessed for their handedness which was compared to the laterality of their presenting pterygium. Patients that possessed bilateral disease comparisons between pterygium size and handedness were made. Correlation statistics were performed to compare patient handedness and pterygium location (right or left). For patients possessing bilateral disease only, the pre-surgical differences between lengths and areas of pterygium were calculated and compared.

RESULTS

A total of 219 patients were recruited into our study. 172 patients possessed unilateral disease and in 47 patients, the disease was bilateral. A significant association was identified between handedness and pterygium laterality (p < 0.001). Patients with right-sided pterygia were more likely to be right-handed (OR 2.327) and left-sided presentations who were more likely to be left-handed (OR 5.717). For bilateral presentations, patients were found to have longer (mean increase 3.50 ± 0.47 mm) and larger (mean increase 4.38 ± 0.48 mm²) pterygia in the eye ipsilateral to their dominant hand.

CONCLUSIONS

A new insight of handedness as a contributing factor to pterygium laterality is consistent with evidence relating to the asymmetrical development of cortical cataract as well as to theories underlying the geometry of ocular UV exposure. A more complete understanding of factors contributing to ocular insolation may further inform as to improved protective measures and provides further evidence for the role of peripheral light focusing in pterygium pathogenesis.