Deficiencies in vitamin D have been tied to many conditions, including autoimmune diseases, lymphoma and various forms of neuropathy. While the relationship between low levels of serum vitamin D and Sjögren’s syndrome have shown contrasting results in previous investigations, a new study from a team of Korean researchers reports vitamin D levels may be associated with dry eye severity in Sjögren’s syndrome.

The study, published in Cornea, enrolled 74 eyes of 74 patients diagnosed with primary Sjögren’s syndrome, and the more severe eye was used for analysis. Only women were included, reflecting the higher prevalence of Sjögren’s syndrome in females, and the average age was 53. The study divided the patients into three groups: vitamin D deficiency (48 patients), vitamin D insufficiency (14 subjects) and a healthy, control group (12 patients).

Exclusion criteria included allergic conjunctivitis, meibomian gland dysfunction above grade 2, any ocular surgeries within the past six months, contact lens wear, punctal plugs, systemic medication use or topical treatments other than artificial tears within the past three months.

The study collected several dry eye measures including tear break-up time (TBUT), Schirmer I values, corneal and conjunctival staining scores and ocular surface disease index (OSDI) results.

The average vitamin D level was 20.4 ± 8.0ng/mL. The study noted a strong negative correlation between serum vitamin D levels and corneal and conjunctival staining scores. Additionally, the Schirmer I value and TBUT showed a significant positive link with vitamin D levels.

The researchers found vitamin D levels didn’t seem to have an impact on OSDI scores.

The current study does have some limitations, including its retrospective design, small sample size and lack of consideration for nutritional status, the investigators noted. Additional studies may also be warranted that expand the dry eye parameters and look at associations with other ocular inflammatory diseases such as graft-vs.-host disease induced dry eye, the investigators added.

Lee JH, Kim SJ, Byun YS, et al. The association of serum vitamin D level with the severity of dry eye parameters in primary Sjögren syndrome. Cornea. December 20, 2019. [Epub ahead of print].