Visual Acuity Poor After Corneal Transplants for Patients With Ocular Trauma

Penetrating keratoplasty (PKP) can help with functional recovery after severe open globe trauma, yet complications occur more frequently than in noninjury-related corneal transplant, according to a report published in Cornea. The largest study on this topic to date reveals that even with strong 12-month graft survival, visual acuity levels were low, and risk factors such as rejection or retinal detachment (RD) should be addressed during patient consults.

The chart review encompassed all patients who underwent PKP after open globe injury (OGI) at a university hospital in Michigan, between January 2000 and July 2017. Forty-six patients (46 eyes) received full-thickness transplants and were followed for 1 year or more — median age was 46 (IQR 23.00, 61.25) years, and 80.4% were men. 

Initial corneal graft 1-year survival was 80.4% (95% CI, 65.8%–89.3%). This rate declined, and by 5 years graft success was 41.7% (95% CI, 26.1%–56.6%), with 20 grafts failing. If a transplant showed no signs of rejection, it achieved a 3-times greater survival rate at 5 years, compared with those having 1 or more rejection events (P =.0012), the study shows. Five-year graft survival rate was also higher in the absence of temporary keratoprosthesis (P =.0277) — but because all RD repairs included this device at time of transplant, its role may be secondary to posterior pathology. Notably, when post-trauma RD was treated surgically within 1 month, graft success was greatly improved (P =.008). 

In multivariable analysis showing hazard ratios (HR), 3 variables substantively impacted graft failure: retinal detachment (HR 3.47; 95% CI, 1.51, 7.99), rejection event (HR 3.29; 95% CI, 1.47, 7.35), and endophthalmitis (HR 6.27; 95% CI, 1.62, 24.38).

Of 42 eyes that did not require enucleation, 15 recovered ambulatory visual acuity (VA) of at least 20/200, and 7 achieved VA of 20/40 or sharper. In 22 eyes, VA improved pre- to postoperatively (P =.003). Multivariable regression analysis for risk of not retaining ambulatory VA revealed 3 important elements; RD (OR 43.88, P =.003), injury outside the workplace (OR 25.05, P =.014), and graft rejection (OR 12.42, P =.024).

Based on data from this study and previous analyses, injury-related pathologies such as RD and astigmatism may limit final vision — with “ocular salvage” being a more realistic expectation than regained acuity, the researchers speculate. They also note that silicone oil is known to prompt endothelial decompensation, so in OGI it may be better to remove tamponade earlier.

In prior research concerning graft failure, presence of pre- or postoperative corneal neovascularization increased rejection risk. “These results have implications for patient selection with careful attention to the presence of NV and appropriate tapering of steroids postoperatively because these eyes tend to be at greater risk for rejection than eyes undergoing PKP for nontraumatic indications,” according to the study.

A limitation of this investigation is its retrospective design which comprises various follow-up periods. Strengths include a large cohort, and use of “survival analysis techniques” that adjust for participants lost to follow-up, and give a more precise measurement of corneal graft results.

“This series suggests a high graft survival rate despite significant ocular trauma. Visual outcomes were, however, poor and limited by noncorneal pathology. RD due to ocular trauma was a significant predictor for both graft failure and poor VA,” the researchers report.