Globe rupture following penetrating keratoplasty: how often, why, and what can we do to prevent it?

PURPOSE

Traumatic globe rupture following penetrating keratoplasty is a life-long postoperative concern. We look at a series of penetrating keratoplasties in one institution and determine the rates of traumatic rupture and the outcomes following rupture. The reasons for persisting wound weakness are reviewed, and recommendations for eye protection based on wound strength are given.

METHODS

A case-control study compared the postsurgical rupture rates for all cases of penetrating keratoplasty to those cases of globe rupture after extracapsular cataract surgery and phacoemulsification. A literature review of corneal wound healing was completed.

RESULTS

Over 10 years 139 penetrating keratoplasties were performed. The incidence of traumatic rupture following keratoplasty was 5.8%. Fifty percent of those with ruptured globes had a visual outcome of hand movement vision or worse. Of the traumatic ruptures, 37.5% occurred in the first postoperative month. The indication for initial keratoplasty did not influence the rupture rate. In comparison, the general rate of penetrating eye injuries in the population was 2.2/100,000 per annum. The rupture rate for extracapsular cataract surgery was 1/221 (0.45%) and 0/6450 for phacoemulsification. Both of these rates were significantly less than after penetrating keratoplasty (P=0.005, P<0.0001).

DISCUSSION

Penetrating keratoplasty cases have a higher rate of globe rupture than other ocular procedures. There are 5 important time periods of wound integrity after penetrating keratoplasty. The highest risk period is the month following surgery, when wound strength is derived almost entirely from sutures. The 18 months following surgery are moderately high risk. The month following removal of sutures is a second high-risk period. In the 6 months following this, the wound has a similar strength to the first postoperative year. Following penetrating keratoplasty the cornea never regains its preoperative strength and remains at risk for traumatic rupture for the remainder of the patient's life.