Effect of an Ophthalmic Gel Containing Xanthan Gum and Sodium Hyaluronate on Corneal Wound Healing After Photorefractive Keratectomy

Abstract

Purpose: : Xanthan gum and sodium hyaluronate have been shown to stimulate corneal healing after superficial mechanical wound in both rabbits (Furrer ISOPT 2004) and humans (Baltaztzis ARVO 2000; Papa ARVO 2004). The aim of the present study was to evaluate the efficacy of a new non preserved ophthalmic gel containing 1% xanthan gum and 0.15% sodium hyaluronate (xan–hyal) in the corneal epithelial wound healing following photorefractive keratectomy (PRK).

Methods: : This was an open, randomized, cross–over study conducted in 12 patients (24 eyes) undergoing bilateral PRK for correction of myopia (–1.00 to –7.00 diopters). The 2 eyes of each patient were operated with an interval of about 30 days. One eye was treated qid with xan–hyal and the other eye tid with CITOPHASE (Farmila), a commercially available stimulator of corneal wound healing containing cytochrome C peroxidase. Treatment started the day of surgery and continued for 5 more days. Corneal wound healing was assessed 1, 2, 3 and 6 days after PRK by slit lamp examination and fluorescein staining. The extent of corneal re–epithelialization (primary efficacy parameter) was graded from 100% (grade 0) to 0 % (grade 4). Superficial punctate staining was evaluated in 5 different areas of the cornea from 0 (no staining) to 4 (staining > 2 mm); a summary score of all areas was then calculated. Ocular symptoms were also assessed by VARS.

Results: : Xan–hyal was highly effective (p<0.0001, Kruskal–Wallis) in promoting corneal wound healing with a median healing time of 3 days. A complete corneal re–epithelialization was observed in 9 out of 12 eyes (75%) on day 3; all eyes were completely healed on day 6. Summary score of the superficial punctate staining decreased significantly (p<0.0001, ANOVA) from 12.0±4.7 (m±SD, day 1) to 5.5±3.3 (day 2) to 1.2±1.7 (day 3); no staining was observed at day 6. Symptoms decreased with time as well. Xan–hyal was well tolerated by all patients. For all the parameters evaluated no statistical significant differences were observed between treatments.

Conclusions: : A new ophthalmic gel containing a combination of 1% xanthan gum and 0.15% NaHa was effective in promoting corneal epithelial healing process after PRK.

Keywords: cornea: epithelium • refractive surgery: PRK • cornea: clinical science