The prevalence and determinants of pterygium in rural areas

Incidence of refractive surprise after phacoemulsification in patients of cataract with primary pterygium

PURPOSE

The purpose of this study was to find the incidence of refractive surprise in patients of cataract with primary pterygium and compare it with patients of cataract without pterygium after phacoemulsification surgery.

METHODS

The present observational study included 30 patients who had cataract with pterygium and 30 patients of cataract without pterygium. A detailed ophthalmic examination was done in all the cases. Horizontal corneal encroachment of pterygium from the limbus was measured. Keratometry and biometric measurements were performed preoperatively to determine the target refraction which was kept between - 0.50D and + 0.50D. The achieved spherical equivalent (SE) and prediction error were calculated postoperatively. A difference of >± 1.00D SE from the targeted postoperative refraction was considered a refractive surprise.

RESULTS

The mean age of patients was 61 ± 8.32 years. The mean extension of pterygium on the cornea was 2.3 ± 0.91 mm. Refractive surprise was seen in 16.7% of cases of cataract with pterygium and 10% of cases of cataract without pterygium.

CONCLUSION

Only cataract surgery can be performed in patient having cataract with primary pterygium of up to 2.3 ± 0.91 mm horizontal corneal length, and the incidence of refractive surprise in these cases is comparable to that in patients of cataract without pterygium.

Evaluation of the Effects of Pterygium and Aging on Limbal Structure Using Optical Coherence Tomography

Previous studies suggest that regions of corneal limbus may possess structural differences. We aimed to investigate the limbal changes associated with pterygium and aging via optical coherence tomography (OCT). Palisades of Vogt epithelial thickness (POV-ET) and Bowman’s membrane epithelial thickness (BM-ET) were measured at the nasal, temporal, superior, and inferior quadrants of patients with pterygium and healthy subjects of different ages. Values were expressed as a ratio that functioned as an index used to evaluate the change of limbus. Ratio values determined for quadrants of the corneal limbus were correlated highly in young healthy subjects. Further, parameter values were significantly greater than those of elder healthy subjects. In young subjects, the temporal and superior quadrants of patients with pterygium were significantly lower than those of healthy subjects. Temporal and superior quadrants of elder pterygium patients affected by both pterygium and age were significantly lower than those of healthy subjects; however, the inferior quadrant of elderly pterygium patients was significantly higher than that of age-matched healthy subjects. Our findings revealed that the thickness of limbal epithelium was negatively correlated with age, while pterygium led to the thinning of the temporal and superior limbal epithelium and inferior limbal epithelial thickening.

Group and Shuffle Convolutional Neural Networks with Pyramid Pooling Module for Automated Pterygium Segmentation

Pterygium is an eye condition that is prevalent among workers that are frequently exposed to sunlight radiation. However, most of them are not aware of this condition, which motivates many volunteers to set up health awareness booths to give them free health screening. As a result, a screening tool that can be operated on various platforms is needed to support the automated pterygium assessment. One of the crucial functions of this assessment is to extract the infected regions, which directly correlates with the severity levels. Hence, Group-PPM-Net is proposed by integrating a spatial pyramid pooling module (PPM) and group convolution to the deep learning segmentation network. The system uses a standard mobile phone camera input, which is then fed to a modified encoder-decoder convolutional neural network, inspired by a Fully Convolutional Dense Network that consists of a total of 11 dense blocks. A PPM is integrated into the network because of its multi-scale capability, which is useful for multi-scale tissue extraction. The shape of the tissues remains relatively constant, but the size will differ according to the severity levels. Moreover, group and shuffle convolution modules are also integrated at the decoder side of Group-PPM-Net by placing them at the starting layer of each dense block. The addition of these modules allows better correlation among the filters in each group, while the shuffle process increases channel variation that the filters can learn from. The results show that the proposed method obtains mean accuracy, mean intersection over union, Hausdorff distance, and Jaccard index performances of 0.9330, 0.8640, 11.5474, and 0.7966, respectively.

Association among pterygium, cataracts, and cumulative ocular ultraviolet exposure: A cross-sectional study in Han people in China and Taiwan

Purpose

Pterygium is an ocular surface disorder mainly caused by ultraviolet (UV) light exposure. This study explored the relationships between six cataract types with pterygium and UV exposure.

Methods

We have previously studied cataracts in residents of three regions in China and Taiwan with different UV intensities. From that study, we identified 1,547 subjects with information on the presence or absence of pterygium. Pterygium severity was graded by corneal progress rate. Cataracts were graded by classification systems as three main types (cortical, nuclear, posterior subcapsular) and three subtypes (retrodots, waterclefts, fiber folds) with high prevalence in middle-aged and elderly people. We calculated the cumulative ocular UV exposure (COUV) based on subject data and National Aeronautics and Space Administration data on UV intensities and used logistic regression to calculate odds ratios for the associations of COUV, cataract, and pterygium.

Results

We found an overall pterygium prevalence of 23.3%, with significant variation among the three regions. Four cataract types (cortical, nuclear, posterior subcapsular, and retrodots) were significantly associated with the presence of pterygium.

Conclusions

There was a significant association between COUV and pterygium, indicating that COUV is associated with the risk of pterygium development and that pterygium is useful as an index of UV exposure. Furthermore, the type of cataract in eyes with pterygium may indicate the level of UV exposure.

Rapid bioprinting of conjunctival stem cell micro-constructs for subconjunctival ocular injection

Ocular surface diseases including conjunctival disorders are multifactorial progressive conditions that can severely affect vision and quality of life. In recent years, stem cell therapies based on conjunctival stem cells (CjSCs) have become a potential solution for treating ocular surface diseases. However, neither an efficient culture of CjSCs nor the development of a minimally invasive ocular surface CjSC transplantation therapy has been reported. Here, we developed a robust in vitro expansion method for primary rabbit-derived CjSCs and applied digital light processing (DLP)-based bioprinting to produce CjSC-loaded hydrogel micro-constructs for injectable delivery. Expansion medium containing small molecule cocktail generated fast dividing and highly homogenous CjSCs for more than 10 passages in feeder-free culture. Bioprinted hydrogel micro-constructs with tunable mechanical properties enabled the 3D culture of CjSCs while supporting viability, stem cell phenotype, and differentiation potency into conjunctival goblet cells. These hydrogel micro-constructs were well-suited for scalable dynamic suspension culture of CjSCs and were successfully delivered to the bulbar conjunctival epithelium via minimally invasive subconjunctival injection. This work integrates novel cell culture strategies with bioprinting to develop a clinically relevant injectable-delivery approach for CjSCs towards the stem cell therapies for the treatment of ocular surface diseases.

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.

Gender and ethnic differences in pterygium prevalence: an audit of remote Australian clinics

CLINICAL RELEVANCE

Developing an accurate picture of the demographic profile and refractive status of Aboriginal and non-Aboriginal individuals with pterygium will facilitate health planning and appropriate deployment of health-care resources in rural Australia.

BACKGROUND

To date, there is a paucity of reports in the literature regarding Aboriginal ocular health and refractive error. This study examines clinical data from a rural ophthalmology outreach clinic - a predominantly Aboriginal population.

METHODS

An assessment was undertaken of data of 293 patients noted to have pterygium present in at least one eye, from a sample of 2,072 individuals seen in rural northern Western Australia in 2017 by the Lions Outback Vision Visiting Optometry Service.

RESULTS

Pterygium was found in 14.1 per cent (n = 293) of patients using the Lions Outback Vision service. The mean age of those with pterygium (n = 293) was 57.1 ± 11.9-years (mean ± standard deviation); 188 were female (64.1 per cent); 260 identified as Aboriginal (88.7 per cent), 22 identified as non-Aboriginal (7.5 per cent) and 11 did not specify (3.8 per cent). There were more males than females with pterygium in the non-Aboriginal group (18.0 per cent versus 6.4 per cent); however, the reverse was true in the Aboriginal group (11.7 per cent versus 17.0 per cent). Analysis of the subjective refractive data in those with pterygium revealed an overall mean spherical equivalent value of +0.66 ± 1.28 DS. The median (interquartile range) best-corrected visual acuity was 0.0 (-0.1 to 0.0) logMAR (6/6 Snellen equivalent).

CONCLUSIONS

This paper increases our knowledge of ocular health in a remote Australian population, with an emphasis on the differences between Aboriginal and non-Aboriginal individuals, males and females.

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

Background

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

Methods

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

Results

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

Conclusion

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

Clinical Aspects of Pterygium in the Presence of Cataract

Two of the most common UV-induced eye affections are pterygium and cataract. They are both defined as progressive diseases that impair patients’ vision and share some common elements in their evolution process. The purpose of this study was to determine whether the presence of cataract influences the clinical signs and symptoms of patients with pterygium. Therefore, we have analyzed 84 patients with pterygium, among which 23 also presented cataract, as an overall study lot, as well as divided by age decades. We have determined that almost all patients with both pterygium and cataract declared extensive UV exposure in antecedents and have also reported a blurred vision. We found no correlation between the presence of cataract and the size of pterygium lesions, or symptoms like foreign body sensation, tearing or symblepharon.