KARACHI: A study published in an international journal has found a high prevalence of dry eye disease in Karachi.
It also demonstrates a range of factors such as age, contact lens wear, ocular allergies, hypertension and diabetes that can influence the disease.
Titled `Distribution and Correlation of Ocular Surface Disease Index Scores in a Non-Clinical Population: The Karachi Ocular Surface Disease Study`, the research was published in the Cureus Journal of Medical Science last year.
The study the first of its kind on the subject in Pakistan was conducted in 2019 by a team of researchers led by Dr Nauman Hashmani of Hashmanis Group of Hospitals.
According to experts, the dry eye disease, also known as dry eye syndrome, is a common condition that occurs when tears are inadequate to provide sufficient lubrication for eyes. This tear instability happens due to a variety of reasons and leads to inflammation and damage to the eye`s surface.
A total of 2,433 individuals over the age of 18 years with no active eye disease participated in the study.
It found that 35 to 60 per cent of the study population suffered from dry eyes with an average age of fewer than 30 years. It also found that older age, smoking and diabetes increased the risk for the disease.
"Many studies have linked the female gender as a risk factor for dry eye disease. One study in Jordan shows no effect of gender at a younger age. However, above 45 years of age, females seemed to have a higher risk for the disease. Androgens regulate the secretory activity of the lacrimal gland and their levels correlate with the signs and symptoms of dry eye disease."
Therefore, it was theorized that due to the lower baseline of androgens in females, the minimum required levels for the optimal functioning of the gland is reached quicker in ageing women. "Additionally, estrogen has been shown to stimulate meibomian gland (the tiny oil glands which line the margin of the eyelids) activity, which exacerbates this problem in postmenopausal women," the study says.
However, it doesn`t show statistically significant gender correlation, though the disease was found to have a direct link with growing age, smoking and comorbidities, such as diabetes.
Past international studies, the research says, suggest that some antihypertensive medications are among the risk factors.
"The exact reasons behind this complex disease are still being explored."
However, we know that excessive digital usage, pollution and increased indoor time in cold and dry environments are major risk factors for the disease,` said Dr Nauman Hashmani, the study author and lead investigator.
Excessive digital usage had been shown to decrease the rate of blinking that caused evaporation of the tear film, exacerbating the disease process, he explained.
"While the study was done before the outbreak of Covid-19, it`s logical to assume that the disease incidence must have increased due to lockdowns and work from home policies.`Increased indoor time in cold and dry environments alters the tear film stability while pollution may cause inflammation that damages and blocks important glands."
About the long-term health implications of the disease and its treatment, he said simple lifestyle changes and medical treatment helped the patient but the problem would affect the quality of life in different ways if left unattended.
"In its mild form, a person can experience eye strain and temporary blurred vision or have difficulty in opening eyes due to intense photophobia. Additionally, due to the lack of a tear film deflecting pathogens, the likelihood of infections rises exponentially."