A Prospective Study of the Effect of Topical Sodium Hyaluronate Immediately Post-PKP on Time to Reepithelialization

Corneal transplant is one of the most common transplant procedures, with over 32,000 recipients in the United States in 2005 and a similar number estimated in 2006. The immediate post-operative period is very important in determining the quality of the graft and often its overall chance of survival. The corneal epithelium is replaced by the recipient epithelium after transplant and this should usually take place in no more than 1 week. This reepithelialization is very important for healing, recovery of the epithelial barrier against infectious agents, and for recovery of vision through the graft. Grafts that take longer to heal can invite not only infection and hinder visual recovery, but be permanently scarred, thinned, and even perforate/fail. Thus rapid reepithelialization is crucial. This becomes even more crucial for monocular patients who need quick recovery.

Currently there is no universal agent that is used to coat the surface at the end of surgery before patching. Previous animal studies have shown that sodium hyaluronate will promote rapid migration of cells as well as stimulate cell proliferation leading to rapid wound closure (1,2). In 1987 one smaller study showed that topical sodium hyaluronate (Healon) may foster improved epithelial healing but it was used intraoperatively and presented technical challenges (3). A more recent non-randomized, retrospective study found that sodium hyaluronate at the end of surgery to coat the ocular surface shortened reepithelialization time. This was in comparison to dexamethasone/oxytetracycline ointment and neomycin/dexamethasone drops, both of which hinder reepithelialization (4). To date we know of no prospective, randomized, double-blinded studies that compare the application of sodium hyaluronate versus nothing (currently the practice at UVA).

Inclusion criteria

• The patients considered for enrollment must be scheduled for penetrating keratoplasty.
• Any high risk patient requiring penetrating keratoplasty.

Criteria for high risk include one of the following:

• Prior failed corneal graft in the operative eye
• Being treated for dry eye at time of surgery
• Having 2 or more quadrants of corneal vascularization
• Having another procedure performed on same eye at time of PKP

Exclusion criteria

• Does not meet one of the criteria for high risk
• Known hypersensitivity to hyaluronate preparations
• Allergic to avian proteins, feathers, or egg products
• Pregnant or breast feeding