A study on prevalence and risk factors of pterygium

 

Gudla Vasantha

 

Assistant Professor, Department of Ophthalmology, Government Medical College, Nizamabad, INDIA.

 

Abstract               Background: A pterygium is a wing-shaped fibrovascular proliferation of the conjunctiva that grows across the cornea. If pterygium is left untreated and its associated risk factors are not avoided, it can result in blindness due to fibro vascular coverage of conjunctiva over the visual axis of the cornea. The prevalence of pterygium varies widely across the globe implying various risk factors which are region specific. Hardly any data is available about the southern part of India. Objective: This study aimed to determine the prevalence and risk factors associated with pterygium. Design: This was a cross-sectional study. Duration: One year i.e; from December 2017 to November 2018. Setting: Government Medical College, Nizamabad. Participants: 100 randomly selected eligible patients attending the Out Patient Departement of Ophthalmology were included in the study.  Methods: The participants were interviewed for potential risk factors of pterygium and later a comprehensive ophthalmology examination was done. Data obtained was entered in MS Excel 2016 and Statistical analysis was done using SPSS version 23. A p-value of less than 0.05 was considered as significant. Results: The prevalence of pterygium among the patients attending ophthalmology OPD was 42%. It was more among the older age group (p<0.05), those working outdoors (p<0.05), those exposed to hot and dry atmospheric conditions (p<0.05) and those belonging to lower socio-economic group (p<0.05). Conclusion: There was a considerably high prevalence of pterygium among study participants. Elderly age group, outdoor workplace, hot and dry atmospheric conditions and low socio-economic status were the observed potential risk factors for pterygium.

Key Words: Pterygium, Prevalence, Risk factors, South India.

 

 

INTRODUCTION

Pterygium is a non-malignant, slow growing, wing shaped proliferation of the fibrovascular tissue, which arising from the subconjuctival tissue, which may extend over the cornea and, thus disturbing the vision. It is organised into head, neck and body. It is a common external ocular disease with prevalence ranging between 0.3% and 36.6% globally. Progressive pterygium is thick, fleshy and vascularised whereas an atrophic pterygium is less vascular and thin. Type I pterygium shows <2 mm encroachment into the cornea. Type II between 2 to 4mm and type III - >4 mm encroachment on to the cornea. Its main clinical presentations are redness, irritation, decreased vision and ocular discomfort. It may also be asymptomatic. It can induce significant astigmatism and cause visual impairment. Pterygium is often preceded by a related non-cancerous condition called pingueculum. The prevalence rate of pterygium varies widely with the variation of altitude, age, gender, occupation and socio economic status. Treatment for pterygium has been improved in recent years. Although the anti-inflammatory drugs and lubricants minimize the patient’s discomfort, it cannot cure it. Surgical removal is the treatment of choice. Methods of pterygium excision by bare sclera technique or McReynolds operation were associated with high recurrence. Adjunct therapies such as β-radiation, thiotepa, 5-FU, and mitomycin C remain controversial. Autologous conjunctival grafting is reported to be the best method, giving both low recurrence rate and few complications. If pterygium is left untreated and its associated risk factors are not avoided or reduced, it can result in visual impairment or blindness due to fibro vascular coverage of conjunctiva over the visual axis of the cornea. This is due to the induction of astigmatism and opacity.

 

MATERIALS AND METHODS

Place Of Study: Government Medical College, Nizamabad.

Type Of Study: This was a cross-sectional study.

Sample Collection: Sample size = 100

Sampling Methods: Systematic random sampling.

Inclusion Criteria: Patients aged above 20 years attending the Ophthalmology OPD.

Exclusion Criteria:

1. Patients below 20 years of age.
2. Patients with severe dry eyes.
3. Patients with primary or secondary Sjogren’s syndrome.
4. Patients with recurrence of pterygium.

Statistical Methods: Data obtained was entered in MS Excel 2016 and Statistical analysis was done using SPSS version 23. A p-value of less than 0.05 was considered as significant.

Ethical Approval: Approval was taken from the Institutional Ethics Committee prior to commencement of the study.

 

OBSERVATIONS AND RESULTS

The prevalence of pterygium in the study population was 42% (n=42). A pterygium was operationally defined as a radially oriented fibro-vascular lesion crossing the nasal or temporal limbus and was graded clinically by slitlamp examination as Grade 1 (atrophic and transparent), Grade 2 (intermediate) and Grade 3 (fleshy and opaque).

 

Table.1: Socio-Demographic Profile Of Study Participants With Pterygium

52% of the subjects having pterygium were male. There was higher incidence of pterygium in the elderly age group (p<0.05, which was statistically significant). About 78.5% of the significant study population resided in urban settings. Lower Socio-Economic Status was highly correlated with the occurrence of pterygium (p<0.05, which was statistically significant).

Table 2: Clinical Profile of Study Participants with Pterygium

The occurrence of Pterygium in the nasal side was 93% in this study. The Pterygium involved both the eyes in 2.3% of the individuals with Pterygium. Only about 14.2% of people gave history of wearing spectacles. About 50% of Pterygium population gives history of smoking, 16% gives history of alcohol intake, 47.6% of Pterygium population are hypertensive while 42.8% is diabetic.