Glaucoma, aphakia strongly predict postpenetrating keratoplasty glaucoma
Aphakia and pre-existing glaucoma are strong risk factors for postpenetrating keratoplasty glaucoma (PPKG), while bullous keratopathy (BK), trauma, pseudophakia and regrafting are modest predictors, according to the findings ofa new meta-analysis.
Reports about the incidence and risk factors of PPKG were searched from the databases of the Cochrane Library, Embase and Medline. Those that used grafts other than a fresh donor cornea were excluded from the review.
Study design and statistical analyses were taken into consideration in the assessment of methodological quality. The incidence of PPKG relative to other conditions, like BK, aphakia and glaucoma, was the primary outcome of the study.
After applying the selection criteria, 31 studies remained eligible for the meta-analysis. Of these, 30 were used to examine the incidence of PPKG and 18 to determine its risk factors; 24 were retrospective and seven were prospective studies.
In a sample of 27,146 patients, the pooled overall incidence of PPKG was 21.5 percent (95 percent CI, 17.8 to 25.7). However, PPKG was defined differently across the studies and the incidences varied depending on which definition was used. The lowest and highest incidence rates reported were 5.3 and 60 percent, respectively.
The 18 studies that evaluated the predictors of PPKG found that the pooled incidence of PPKG was greatest in individuals with aphakia and pre-existing glaucoma. Moreover, for those with BK, a preoperative diagnosis of trauma, pseudophakia and regrafting, the pooled incidence was slightly higher.
Finally, those who received penetrating keratoplasty combined with intraocular lens implantation and extra capsular cataract extraction did not show higher risks of PPKG incidence.