Obstruction of the nasolacrimal duct leads to the excess overflow of tears called epiphora, a common complaint among ophthalmic patients. Physiologically, the mucosa of the lacrimal sac is very resistant to infection, occasionally distal obstruction of the nasolacrimal duct may occur, which can trigger inflammatory and infectious processes1.
Pathologies of tear duct drainage account for about 3% of eye consultations, of which dacryocystitis is by far the most common cause of epiphora. Dacryocystitis is inflammation of the tear sac, and is classified according to the time of evolution in acute and chronic2. Of these two varieties, chronic dacryocystitis is the most common, and is associated with nasolacrimal duct obstruction. Chronic dacryocystitis usually affects both children and adults more often women ≥ 40 years old.3.
The prevalence of chronic dacryocystitis exceeds acute infection, this is related to the microbiological pathogenesis of dacryocystitis, as well as the patterns of geographic variation of the etiological agents in these infections. Another influencing factor is the co-occurrence of nasal pathologies with the presence of chronic dacryocystitis1,4.
Causes of chronic dacryocystitis range from idiopathic causes to secondary causes to infectious processes, local or systemic inflammations, nasal trauma, nasal polyps, nasal septum deviation, hypertrophic rhinitis, lower corneal hypertrophy, congenital disorder or neoplasms, which triggers a buildup of tears in the sac, mucoid secretions and flaky cells, which cannot be drained to the nose, but usually overflow to the outside of the eye5. The accumulation of cell debris, mucus and tears leads to the arrival of bacteria and with it the origin of dacriocystitis6.
Chronic dacryocystitis associated with bacterial infections represents around 61–95% of all dacryocystitis6,7. The causative agents of the infection colonize and multiply in the nasolacrimal duct and produce relevant symptoms such as epiphora, pyorrhea, ophthalmodynia and conjunctival hyperemia, among others, which affect the quality of life of patients. Delayed treatment can trigger infection extension to other tissues, such as orbital cellulitis, abscesses, meningitis, cavernous sinus thrombosis, and sepsis7.
Symptoms associated with chronic dacryocystitis include continuous epiphoria, regurgitation of mucoid or mucopurulent secretions to digitopression in the tear sac or by infusing fluids into the tear drainage system2.
Vitamin D is a known steroid hormone which can be endogenously synthesized or ingested in the diet. The role of vitamin D has been established at the eye level. Several studies describe the presence of vitamin D receptors in numerous eye structures, such as the corneal epithelium, lens, ciliary body, corneal endothelium and pigment epithelium, ganglion cells and retinal photoreceptors8,9. Vitamin D hydrolase has also been shown to be present in various structures of the human eye, so a conversion of 25-hydroxyvitamin D to the active form 1.25-hydroxyvitamin D or calcitriol in the eye has been proposed. Similarly, epithelial limb cells, aqueous and vitreous humor and tear film could also be considered sources of origin of vitamin D in the eye9.
An improvement in cornea epithelial bore has been reported in patients with vitamin D supplementation, because it regulates narrow joints between cells10. In addition, vitamin D immunomodulatory mechanisms have been proposed in inflammatory eye processes, expressed in inhibition of inflammatory cell migration (Th1 and Th2 cells), increased interleucine synthesis (IL) 10, reduction of inflammatory cytokines such as IL6, C-reactive protein and tumor necrosis factor (TNF) alpha11,12. Other described functions of this vitamin is act as a stabilizer of the eye surface, through the reduction of the osmolarity of tears12. So vitamin D can influence the functions of the tear system10.
Normal levels of vitamin D in adults according to the Center for Disease Control and Prevention (CDC) range from 20–80 ng/ml, described as vitamin D deficiency at levels below 20 ng/ml and severe vitamin D deficiency for levels below 10 ng/ml). Tests to evaluate vitamin D may be total levels of 25 (OH) D (diagnosis and monitoring of vitamin D deficiency) and measurement of the 25 (OH) D2 and 25 (OH) D3 (treatment follow-up) 13.
Human studies have determined a link between elevated serum vitamin D levels with improved symptoms in dry eye syndrome14, and highlighting that 25-hydroxyvitamin D deficiency linked to lack of sun exposure are associated with dry eye syndrome10. That is, adequate levels of vitamin D have a positive impact on dry eye syndrome.
According to the review, this is the first study to evaluate the association between vitamin D levels in the presence of chronic dacryocystitis.
H0: There is no association between chronic dacriocystitis and vitamin D levels.
H1: Chronic dacriocystitis is associated with vitamin D levels.
Based on the background described, it is proposed to determine the association between vitamin 25-OH-hydroxyvitamin D levels in patients with chronic dacryocystitis.