Review: Role of vitamin D in glaucoma requires further investigation
Click Here to Manage Email Alerts
Low vitamin D is a potential risk factor for glaucoma, but further research is needed to determine the exact mechanism and evaluate the temporal and causal relationship.
“The aim of this review is to summari[z]e the evidence implicating low vitamin D status as a potential risk and prognostic factor in primary open-angle glaucoma (POAG) and identify future areas of research,” Brandon Huynh, of Westmead Hospital in Australia, and colleagues wrote. “There has been increasing interest in vitamin D status and glaucoma as low vitamin D has been identified by some studies as an independent risk factor for glaucoma.”
Researchers cited studies that proposed oxidative stress contributes to retinal ganglion cell (RGC) degeneration and glaucoma, as well as studies that showed altering reactive oxygen species can either trigger or prevent RGC apoptosis. Other studies hypothesized that the role of vitamin D in glaucoma is due to its role as an antioxidant and in suppressing genes involved in inflammation.
“Ultimately, the multiple complex pathways leading to RGC damage under oxidative stress are likely varied and overlapping,” researchers wrote. “The relationship between vitamin D and glaucoma may be a consequence of altered vitamin D metabolism in affected individuals or due to low vitamin D levels.”
Researchers noted that there are varying benchmarks for low vitamin D status and different ways to measure serum 25(OH)D, although there is consensus in the literature that low vitamin D is common worldwide.
The investigators cited findings of significant associations between low vitamin D and primary open angle glaucoma. Studies found that IOP declined with vitamin D administration and that participants with glaucoma had lower serum 25(OH)D.
However, other studies showed “conflicting results,” such as no IOP differences between participants with low vs. high serum 25(OH)D.
Nonetheless, the authors wrote that the research “lend[s] significant weight to pursue further studies.” Some avenues of future research suggested by the researchers would address the limitations of previous studies, such as investigating intramuscular, topical or other supplementation methods. Other studies could address current gaps in the research, such as the relationship between sun exposure and primary open angle glaucoma.
“There is a potential physiological role for vitamin D as an anti-inflammatory agent in the oxidative stress-driven pathogenesis of POAG; however, many interacting phenotypic, genetic, epigenetic and environmental factors are likely involved,” researchers wrote. “The studies to date do not provide a direct link between vitamin D deficiency and POAG; however, they do lend significant weight to pursue further studies.”
Perspective
Back to Top
Various reports investigating the association of oxidative stress and the pathogenesis of glaucoma have increased the interest in researching low vitamin D as a potential risk factor for developing POAG. While old studies identify low vitamin D as an independent risk factor for glaucoma, the authors of this review concluded that current studies do not support a direct link between vitamin D deficiency and POAG development, nor is there confirmation that vitamin D supplementation is preventive or therapeutic for POAG. Limitations to this review include the assessment of studies from last century, studies using non-human subjects and minimal studies assessing vitamin D administration other than oral supplementation. The authors therefore comment on a need for future studies that focus on vitamin D supplementation via topical or intramuscular administration.
It is established that low vitamin D is associated with cardiovascular disease, diabetes and autoimmune conditions. This knowledge highlights the importance of recognizing potential correlations between a patient’s uncontrolled systemic vascular disease, increased retinal ganglion cell loss and glaucomatous disease progression. The practicing optometrist must recognize that POAG is a multifactorial disease that requires a spectrum of systemic and ocular treatment and management.
Collapse
Read more about
Click Here to Manage Email Alerts