Improvement of the ocular surface using hypotonic 0.4% hyaluronic acid drops in keratoconjunctivitis sicca

Background The ocular surface changes of keratoconjunctivitis sicca (KCS) c ould be the result of the effect of an altered tear film on the epithelial environment. Purpose To evaluate the possibility of improving the environmental conditio ns of the ocular surface by lowering tear osmolarity, increasing tear film volume and stabilising the tear film. Also, to study the effect of such an improvement on the epithelial cells of the ocular surface. Methods One hundred and thirty-five patients with a diagnosis of KCS were t reated on a randomised basis with either unpreserved hypotonic 0.4% hyaluro nic acid (HHA) eye drops or 0.3% hydroxypropylmethylcellulose plus 0.1% Dex tran 70 (HPMC) eye drops 6 times a day for 60 or 90 days. In all patients a Schirmner I test, break-up time (BUT), ocular surface staining with 1% Ben gal Rose, or 2% fluorescein, as well as subjective symptoms, were recorded before and 15, 30 and 60 days after the beginning of the study. Patients we re divided into three subgroups and the effect of the treatment was studied using three different techniques: the tear fencing test, conjunctival impr ession cytology and tear osmolarity measurement. Results Improvements in BUT, vital staining, Schirmer I and symptoms were r ecorded in both groups of treatment, with significant differences for patie nts treated with 0.4% HHA. On day 60, 30 min after installation: tear fenci ng patterns changed from 100% pathological (types III-IV) to 93% physiologi cal (types I-II) in the 0.4% HHA group and from 100% pathological to 78% ph ysiological in the 0.3% HPMC group (p < 0.01 between groups). Tear osmolari ty 0shifted from 353 +/- 23 to 305 +/- 6 mosmol/l in the 0.4% HHA group and from 346 +/- 15 to 336 +/- 8 mosmol/l in the 0.3% HPMC group (p < 0.001 be tween groups). On day 90, the impression cytology score improved from 1.2 t o 1.9 in the 0.4% HHA group while it did not change in the 0.3% HPMC group (p < 0.05 between groups). Conclusion In KCS appropriate treatment with a hypotonic 0.4% HHA tear subs titute can change the tear environment and results in improvement of the ep ithelial conditions of the ocular surface.