Patients who are older than 60 years are significantly more likely to develop dry eye disease (DED) compared with younger populations, according to a meta-analysis published in The Ocular Surface. The findings suggest that aging is a risk factor in DED.
Researchers reviewed studies published in PubMed, EMBASE, and Web of Science with the search terms “dry eye,” “dry eye disease,” “ageing,” “aging,” “age,” “senescence,” and “cellular senescence.” Articles were required to have an experimental study design with original data results. Studies were excluded if they assessed patients with Sjogren syndrome, used test subjects other than humans and mice, utilized gene manipulation, or were epidemiologic studies with less than 3000 participants.
Of the 14 large, epidemiological studies found, 8 were analyzed for DED prevalence. The prevalence of DED in patients 60 years and older was 9.2% (5519 of 60,107), which resulted in an odds ratio of 1.313 (95% confidence interval [CI]; 1.107, 1.557) when compared with the younger age group (<60 years).
The researchers identified 44 studies relating to ocular changes due to aging. Of those, 25 articles discussed decreased tear volume, decreased tear break up time, and increases in tear osmolarity as age increased. They also found 24 studies that reported on changes in the ocular surface, including decreased barrier epithelial barrier function and an increase in antigen-presenting cells (APCs), and 13 studies that examined the meibomian gland, finding decreases in density and diameter and increases in dropout and obstruction, leading to tear film instability. Also, 13 studies discussed age-related changes to the lacrimal gland.
The increased prevalence of DED with increased age suggests that aging is a risk factor for DED, researchers believe. The changes to the ocular structures and functions that the research team noted help explain how aging can contribute to the pathophysiology of DED.
“Our systematic review regarding age-related alteration of the ocular surface reports a decrease of acinar density and diameter in the lacrimal gland and meibomian gland accompanied by the infiltration of inflammatory immune cells (mainly T cells and APCs),” researchers explain. “As a result, the quality and quantity of tear film on the ocular surface became unstable, yielding a decrease of corneal and conjunctival surface integrity.”
A limitation of this study is the exclusion of patients with Sjogren syndrome, which was intentionally done to focus on the effect of natural aging. Additionally, all articles related to DED were included, regardless of their diagnostic definition or severity. Last, researchers excluded data based on sex.
Kitazawa K, Inomata T, Shih K, et al. Impact of aging on the pathophysiology of dry eye disease: a systematic review and meta-analysis. Ocul Surf. 2022;25:108-118. doi:10.1016/j.jtos.2022.06.004