Decreased tear levels of neuropeptide Y (NPY) and calcitonin gene–related peptide (CGRP) are linked to damaged tear function, according to a paper published in the Archives of Ophthalmology.
Dr Alessandro Lambiase et al., Department of Ophthalmology, Campus Bio-Medico, University of Rome, Italy, studied 19 patients with dry eye disease and 12 healthy participants. All patients were examined by slitlamp examination, Schirmer testing, fluorescein staining, and tear film break-up time. Tear samples were gathered, along with the grading of dry eye severity. Substance P, calcitonin gene–related peptide (CGRP), neuropeptide Y (NPY), vasoactive intestinal peptide, and nerve growth factor (NGF) concentrations were assessed by enzyme-linked immunoassay and linked to the clinical results.
It was found that nerve growth factor tear levels were significantly higher in patients with dry eye disease. CGRP and NPY concentrations were significantly reduced compared to healthy participants.
The severity of dry eye was directly linked to NGF and inversely correlated with CGRP and NPY tear levels. Conjunctival hyperemia and fluorescein staining results were directly correlated with nerve growth tear factor.
CGRP was directly linked to Schirmer test results and NPY was inversely linked to tear film break-up time. NGF tear levels strongly correlate with corneal epithelial damage. The study suggests the importance of NPY, CRGP and NGF as markers of dry eye severity.