Abstract
Abstract: :
Purpose: To analyze the influence of mechanical versus nonmechanical trephination of donor and host corneas on superficial, peripheral corneal neovascularization occurring after non-high-risk keratoplasty as a "model" of corneal angiogenesis. Methods: Patients of the prospective Erlangen non-high-risk keratoplasty study with standardized corneal photographs taken preoperatively and one year later were analyzed (n=184). Slides of these photographs were projected (magnification: x100) and corneal vessels graded in a standardized semiquantitative fashion into 5 categories with regard to limbus, sutures and host-graft-junction in each of 12 corneal sectors. In 32 patients a mechanical (17.4%) and in 152 a nonmechanical trephination of host and donor tissue was performed (193 nm excimer laser; 82.6%). Statistical analysis was done using Fisher's exact and Mann-Whitney test. Results: Corneal neovascularization within the first postoperative year is a common phenomenon occurring in 53% of patients and was lower in the nonmechanical (73 of 152 [48%]) compared to mechanical trephination group (24 out of 32 [75%]; p<0.001). In contrast, regarding the maximal extent of neovascularization (i.e. vessels reaching the interface or growing beyond), there was no significant difference between nonmechanical (8.2%) and mechanical (16.7%) trephination (p=0.074). Conclusions: Nonmechanical trephination using the 193 nm excimer laser in non-high-risk keratoplasties reduces corneal neovascularization occurring within the first postoperative year. This indicates that in the non-high-risk setting, development of postoperative corneal neovascularization may be affected by the trephination technique and subsequent wound healing response.
Keywords: 369 cornea: clinical science • 483 neovascularization • 607 transplantation