Objective: High-pressure physiological saline isotonic solution (HPpSIS) delivery into the nasal cavity was found to modulate the local expression of immune cells, increase NGF protein, and enhance the NGF receptors' expression. Since the nasal cavity directly communicates with the eye and as NGF was previously found to ameliorate the symptoms of dry eye when topically delivered, the aim of this study was to establish whether the HPpSIS might ameliorate ocular dryness and tear film composition.
Subjects and methods: This is an observational self-controlled case study carried out on 16 patients with dry-eye diagnosis, concerning 3-month self-administration of HPpSIS and two serial assessments of the ocular surface and tear film. OSDI questionnaire was used for ocular symptoms of dryness. BUT and Schirmer tests were used for qualitative and quantitative tear film analysis. The lipid composition was also examined. R-studio was employed for the detection of the difference between the pre- and post-analysis.
Results: On the basis of the OSDI questionnaire, the study population was divided into severe (61.1%), moderate (5.5%), and mild (16.6%) dry-eye symptoms. OSDI score was significantly reduced after HPpSIS (p<0.05). BUT and TMH values also ameliorated after HPpSIS (p>0.05), although not significantly. The lipid layer improved statistically (p<0.05) and correlated positively with OSDI grading. The variability of presentation in the numerical distribution before and after therapy suggests poor test sensitivity.
Conclusions: HPpSIS showed a positive effect in reducing OSDI scores and ameliorating tear film quality. The possibility of an endogenous HPpSIS-induced NGF should be taken into account in dry-eye therapy.