Corneal hyaluronan content during post-ablation healing: evidence for a transient depth-dependent contralateral effect.

The hyaluronan content during wound healing following excimer laser photoablation was investigated. Rabbit corneas were photoablated (Summit Omnimed, 193 nm, 5 mm diameter, 50 microns and 100 microns depth). Central optical zones of photoablated and contralateral corneas were removed 7, 30 and 90 days after surgery. Corneas from 2 untreated rabbits were used as control. Hyaluronan content was determined after pepsin-solubilization using an alkaline-phosphatase linked hyaluronectin sorbent assay. The hyaluronan content of non-photoablated contralateral corneas was significantly increased and the changes appeared depth dependent. Hyaluronan content returned to control levels by the first month at 50 microns depth and by the third month at 100 microns depth in contralateral corneas. The hyaluronan content of the photoablated corneas was not significantly different from that of the non-photoablated contralateral sample regardless of the depth of photoablation. By contrast, the hyaluronan content of the treated corneas was significantly higher than that of the controls during the first month post-surgery and returned to control values by the third month. Thus the hyaluronan contents in the photoablated and contralateral corneas after excimer laser corneal photoablation were very similar during wound healing. This study shows that excimer laser photoablation induced transient depth-dependent contralateral alterations of the hyaluronan content.