Hyaluronic acid combined with mannitol to improve protection against free-radical endothelial damage: experimental model.

PURPOSE: To evaluate the protective properties of combined sodium hyaluronate 2% and mannitol 0.5% (Visiol) on the corneal endothelium in the presence of oxidative stress induced by hydrogen peroxide (H(2)O(2)). SETTING: Instituto Oftalmológico de Alicante, Universidad Miguel Hernández, Alicante, Spain. METHODS: This was an exploratory randomized controlled parallel-group, masked-assessor study of 3 sodium hyaluronate-based ophthalmic viscosurgical devices (OVDs): Visiol, Healon (sodium hyaluronate 1%), and Viscoat (sodium hyaluronate 3%-chondroitin sodium 4%). The OVDs were tested for protective effects on the endothelium following oxidative stress induced by H(2)O(2) at increased concentrations: control (lactated Ringer's solution), 1 mM, 10 mM, and 100 mM. Groups without OVD were used as controls at the same concentrations of peroxide. Each animal received the same treatment in both eyes (10 eyes per group). Endothelial cell lesion was assessed using the Janus green photometry absorbance technique. RESULTS: At 10 mM peroxide concentration, the value of endothelial cell lesion was significantly lower in the Visiol (16.8%, P=.0056), Healon (22.2%, P=.0302), and Viscoat (21.6%, P=.0336) groups than in the control group (29.4%, no OVD). There was a trend in favor of Visiol to more efficiently reduce cell lesions of the endothelium, than Healon (P=.055) and Viscoat (P=.1013). Values of endothelial cell lesion at peroxide concentrations of 1 mM and 100 mM showed the same trends than those observed at 10 mM. CONCLUSIONS: All of the OVDs tested efficiently reduced endothelial lesions against free radicals compared with the control group in which no OVD was used. The following sequence for the efficacy of endothelial cell protection was established: Visiol>Viscoat>Healon>no OVD.

Efficacy and safety of 0.18% sodium hyaluronate in patients with moderate dry eye syndrome and superficial keratitis.

BACKGROUND: Sodium hyaluronate (SH) is used in patients with dry eye. We evaluated the efficacy and safety of SH and carboxymethylcellulose (CMC) in the treatment of dry eye syndrome with superficial keratitis. METHODS: A total of 22 patients with moderate dry eye and superficial keratitis were enrolled in a prospective, randomised, masked-observer, parallel-group, single-centre study. Patients were randomly assigned to a 0.18% SH or 1% CMC solution for a 2-month period. In addition to the commonly assessed parameters in patients with dry eye (among others symptoms and corneal staining with fluorescein), flow cytometry analysis of CD44, HLA DR expressions in impression cytology was investigated as a potential efficacy parameter. RESULTS: Both treatments improved the symptoms and ocular surface and were well tolerated. SH significantly (p<0.05) decreased CD44 values compared with CMC. Comfort was significantly (P<0.05) better in the SH group than that in the CMC group throughout the study. Recovery in keratitis (type, extent and depth) and symptoms were faster in the SH group than in the CMC group. Blurred vision was reported by patients in the CMC group only. CONCLUSIONS: SH was well tolerated and tended to show a faster efficacy than did the CMC-based formulation in patients with moderate dry eye and superficial keratitis. SH could therefore advantageously be prescribed from the early stages of dry eye disease. This study also showed that flow cytometry in impression cytology specimens is a reliable tool for exploring the ocular surface at the epithelial level and that CD44, in addition to HLA DR, could be an interesting endpoint for future trials in dry eye syndrome with products based on SH.