GRAFT ENDOTHELIUM AFTER MECHANICAL AND NONMECHANICAL CORNEAL TREPHINATION IN PENETRATING KERATOPLASTY

97th DOG Annual Meeting 1999

K85
GRAFT ENDOTHELIUM AFTER MECHANICAL AND NONMECHANICAL CORNEAL TREPHINATION IN PENETRATING KERATOPLASTY

B. Seitz, A. Langenbucher, M. M. Kus, N. X. Nguyen, M. Küchle

Background and Purpose: Nonmechanical corneal trephination results in significantly less corneal astigmatism and significantly better visual acuity after penetrating keratoplasty (PK) [1]. The purpose of this study was to assess the impact of nonmechanical trephination on the graft endothelium.

Patients and Methods: Inclusion criteria for this prospective, randomized, cross-sectional, clinical study were: 1. Time interval 10/1992 to 12/1997, 2. One surgeon (G.O.H.N.), 3. Primary PK, 4. Fuchs' dystrophy (diameter 7.5/7.6 mm) or keratoconus (diameter 8.0/8.1 mm), 5. No previous intraocular surgery, 6. 16-bite double running diagonal suture. In 179 patients (mean age at the time of surgery 51±18 (range 15 to 83) years) PK was performed using either the 193-nm Meditec excimer laser (EXCIMER) along metal masks with eight "orientation teeth/notches" (53 keratoconus, 35 Fuchs') or motor trephination with the Mikrokeratron (Geuder, Germany) (CONTROL: 53 keratoconus, 38 Fuchs'). For donor trephination from the epithelial side an artificial anterior chamber was used in both groups. In 27% of EXCIMER and 29% of CONTROL a triple procedure was performed. Specular microscopy (EM-1000, Tomey) was performed before removal of the first suture (15.2±4.2 months) and after removal of the second suture (21.4±5.6 months). In EXCIMER/CONTROL 44%/49% of the grafts were organ-cultured, mean donor age was 58±19/59±20 years, mean post-mortem time was 19±16/21±18 hours, mean preservation time was 177±191/191±198 hours.

Results: In EXCIMER/CONTROL, preoperative donor endothelium was 2859±222/2917±183 cells/mm². Neither "all-suture-in" (1762±455/1801±389 cells/mm², p=1.0) nor "all-suture-out" endothelial cell count (1296±508/1312±524 cells/mm², p=0.66) did differ significantly between EXCIMER and CONTROL. Cell count was not significantly less in Fuchs' dystrophy than in keratoconus before (1689±414/ 1860±413 cells/mm², p=0.24) and after suture removal (1235±533/1380±499 cells/mm², p=0.12).

Conclusions: Besides now well-established optical advantages, nonmechanical trephination from the epithelial side seems to have no drawbacks concerning the graft endothelium after PK.

[1] Seitz B. et al: Nonmechanical corneal trephination with the excimer laser improves outcome after penetrating keratoplasty. Ophthalmology 1999 (in press)

Department of Ophthalmology, University of Erlangen-Nürnberg, Schwabachanlage 6, D-91054 Erlangen.

Supported in part by BMBF (IZKF Erlangen, B13)

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