Comparison of Hypotonic and Isotonic Solutions Containing Sodium Hyaluronate on the Symptomatic Treatment of Dry Eye Patients

Abstract

This study was designed to compare the efficacy of two artificial tears both containing hyaluronic acid but differing in their osmolarity. A multicentric double-masked, crossover clinical trial was performed in which 158 subjects were randomized to receive either hypotonic or isotonic artificial tears up to 6 times a day. Both treatments were effective in improving signs and symptoms to a similar extent. No adverse events were reported. It was concluded that hypotonic and isotonic eye drops are comparable for the symptomatic treatment of patients suffering from dry eye syndrome.

Effectiveness of sodium hyaluronate eyedrops in the treatment of dry eye

“…Regarding osmolarity, elevated tear osmolarity is a characteristic of dry eye and directly compromises ocular surface integrity [5]. However, the results of studies that have compared isotonic and hypotonic eyedrops for this condition are contradictory [1,9]. It has been reasoned that the osmolarity of eyedrops has little effect on symptoms or signs because their reductions in tear osmolarity are of a short duration and that relative to the tear film in dry eye, even formulations isotonic with normal tears are hypotonic [9].…”

“…However, the results of studies that have compared isotonic and hypotonic eyedrops for this condition are contradictory [1,9]. It has been reasoned that the osmolarity of eyedrops has little effect on symptoms or signs because their reductions in tear osmolarity are of a short duration and that relative to the tear film in dry eye, even formulations isotonic with normal tears are hypotonic [9]. Considering the available evidence it seems likely that preservative and osmolarity differences between the treatments were of minor importance, but would have acted to decrease the effectiveness of the 0.1% SH drop and increase that of the 0.3% SH drop.…”

“…It consists of repeating disaccharide units of N-acetyl-D-glucosamine and sodium-D-glucuronate. Several authors have reported the use of SH in artificial tears [1,3,8,9]. Between blinks its relatively high viscosity improves tear film stability and reduces washout from the ocular surface, but reduced viscosity under shear stress permits uninterrupted blinking.…”

TRPV1 Activation Is Required for Hypertonicity-Stimulated Inflammatory Cytokine Release in Human Corneal Epithelial Cells

“…These tear gland dysfunction and tear film instability; thus, corneal erosion and opacification may ensue. Although therapeutic approaches such as hypotonic or isotonic artificial tears provide symptomatic relief in dry eye disease patients by lowering their tear osmolarity, 3,4 development of drugs that can effectively suppress receptor-mediated inflammation is limited.…”

Effect of Hypotonic 0.4% Hyaluronic Acid Drops in Dry Eye Patients: A Cross-Over Study

“…25 Sodium hyaluronate eye drops have been used in several studies for the treatment of dry eye. [26][27][28][29][30] Experimental data show that sodium hyaluronate eye drops do not alter the normal conjunctival epithelium, 31 do not interfere with the secretory processes of goblet cells, 32 and do not damage intercellular junctions. 33 Moreover, sodium hyaluronate eye drops have a longer ocular surface residence time 34,35 and increase precorneal tear film stability, 36,37 corneal wettability, and the healing time of corneal epithelium.…”