Use of amino acids in refractive surgery

To assess the influence of amino acid supplements on corneal fibroblast activity during corneal healing in patients with chronic ulcers, as well as after refractive surgery when delayed re-epithelialization had been observed in the fellow eye.

Studies were conducted in vitro on eye bank eyes, and in vivo. In vitro cultures of rabbit corneal fibroblasts were enriched with progressively higher concentrations of amino acids. The human eye bank cornea study involved corneal epithelium removal, with corneas kept for 7 days in standard storage medium, either simple or enriched with amino acids. Clinical studies included treatment of two groups: Group 1 included six eyes of six patients with chronic epithelial defects, resistant to usual treatment; Group 2 included 21 eyes of 21 patients with delayed re-epithelialization after PRK in the first eye (12 +/- 3 days). Group 1 was treated for 1 month, and Group 2 received treatment preoperatively and postoperatively after surgery in the fellow eye until re-epithelialization was achieved. All patients received 13 amino acids and Vitamin C in three tablets, three times per day.

Cultures of rabbit corneal fibroblasts showed that progressively increasing amino acid supplements led to an increase in the percentage of fibroblasts. De-epithelialized human eye bank corneas incubated with amino acids showed thicker and better organized re-epithelialization when compared to corneas incubated in simple standard storage media. In the clinical study, five eyes in Group 1 showed substantial improvement, one eyes remained unchanged. All eyes in Group 2 showed complete re-epithelialization within 60 hours after surgery.

Results suggest improvement of re-epithelialization when an increase of serum and tear film amino acids is obtained through oral administration.