Effect Of Topical Lubricants On The Corneal Surface Recovery And Patient Discomfort After Prk. A Prospective, Controlled, Observer Masked Study, Comparing Two Preservative Free Products. The Sysprk Study.

To compare the effect of two preservative free (PF) artificial tears, one containing carmellose (control group) vs another containing hyaluronic acid and hydroxypropyl-guar (HA+HP-guar) (study group), on the healing of the corneal epithelium and the ocular discomfort after bilateral photorefractive keratectomy (PRK) surgery.

Clinica Novovision Madrid, Spain

This is the final report of randomized, dual-arm, prospective, interventional, single masked study. 68 patients that were scheduled to have PRK to correct myopia were randomized in two groups. 34 patients (68 eyes) in the study group, and 34 patients (68 eyes) in the control group. Ocular exams were performed at post-op days 1, 4, 7 and at months 1 and 3, measuring the diameter of the de-epithelized cornea and the fluorescein staining using, the Oxford scale. The tear film was evaluated using the Keratograph. A Visual Analogic Scale (VAS) pain evaluation was performed by the patient at every post-op visit.

Both groups were comparable in terms of age, gender and preop refractive error magnitude. At post-op day 4, 97% of the study eyes vs 84.4% of the control eyes were completely re-epithelized (p=0.01).  A statistically significant less ocular pain was observed at day 3 post-OP in the (HA+HP-guar) group (4.29+/-1.9 vs 5.43+/-2.3 p=0.03). No statistically significant differences were observed beyond post-op day 7 on the healing of the corneal epithelium, NIKBUT and the self-perceived ocular discomfort between the two groups.

The current study shows a faster healing of the corneal epithelium and less ocular pain after PRK with the use of topical lubricants containing (HA+HP-guar) compared with the use of conventional carmellose artificial tears. This could be due to the trophic effect that the combination of hyaluronic acid and hydroxypropyl-guar could have on the epithelial cells of the cornea. This faster recovering seems to have a significant additional benefit reducing the ocular pain-discomfort in the first days after PRK surgery. Both groups had no differences in the visual or refractive outcomes.