Abstract
Purpose :
Preliminary evidence states hypovitaminosis D as a risk factor for the development of peripheral neuropathy in Sjogren’s syndrome (SS); however, the relationship between vitamin D levels and ocular surface disease in these patients has not been carefully studied. The current study examines the interplay of SS and vitamin D deficiency on corneal nerves. We hypothesize that hypovitaminosis D, SS patients will exhibit a reduction in the corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD) and corneal nerve fiber length (CNFL). We also hypothesize that they will report greater dry eye and dry mouth symptoms.
Methods :
Subjects were enrolled into one of four arms; SS patients with a vitamin D deficiency (<30 ng/mL) (Group 1), SS patients with sufficient vitamin D (≥30 ng/mL) (Group 2), non-SS patients with a vitamin D deficiency (Group 3) and lastly, non-SS patients with sufficient vitamin D (Group 4). Blood samples were tested for serum levels of total 25-hydroxy Vitamin D (D2+D3). Corneal nerves in the sub-basal plexus were captured using confocal microscopy imaging on the Heidelberg Retina Tomograph II (HRTII) and analyzed with ImageJ. Tortuosity was scored subjectively by two independent graders. Dry eye and dry mouth symptoms were assessed using the Ocular Surface Disease Index (OSDI) and a dry mouth questionnaire, respectively.
Results :
58 subjects are enrolled to date, 12 in Group 1, 21 in Group 2, 10 in Group 3, and 15 in Group 4. Subjects in Group 1 exhibited significantly less CNFB as compared to Group 2 (P=0.015). The mean CNFDs were 0.604 and 0.825 for Groups 1 and 2, respectively. Additionally, Groups 1 and 2 exhibited trending, but at this time, insignificant differences in CNBD and CNFL (Table 1). SS subjects with vitamin D deficiency also showed increased tortuosity and irregular distribution of fibers (Figure 1). Subjects in Groups 3 and 4 showed no appreciable difference in CNFB, CNBD or CNFL (Table 1).
Conclusions :
Our data suggests that hypovitaminosis D contributes to corneal neuropathy in SS patients. SS patients with vitamin D deficiency showed abnormal CNFD and morphology compared to SS patients with sufficent vitamin D, while non-SS patients did not vary between sufficient and insufficient vitamin D levels. Future work will focus on enrolling patients with a wider range of serum vitamin D levels and studying the effects of systemic vitamin D supplementation on corneal nerves.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.