title: Corneal endothelial cell loss after nonmechanical penetrating keratoplasty depends on diagnosis: a regression analysis.
abstract: OBJECTIVE
  To assess the impact of diagnosis on corneal endothelial cell loss after nonmechanical penetrating keratoplasty (PK) with regression models.
  
  
  METHODS
  Five hundred eighty-nine eyes [273 with keratoconus (group I; PK only), 187 with Fuchs' endothelial dystrophy (group II; 77 PK only and 110 triple procedures) and 129 with bullous keratopathy (group III; 115 pseudophakic and 14 aphakic eyes)] were included in this prospective study. The time course of the endothelial cell density after PK was assessed by specular microscopy. Endothelial cell density was analyzed in cross-sectional fashion at 6 and 24 months follow-up and in longitudinal manner (follow-up 2.4+/-1.8 years) with linear and exponential regression models (minimizing the residuum between observed and predicted endothelial cell count). Donor age, post-mortem time, storage time and ratio of organ-cultured to short-term-preserved donor corneas did not differ significantly between groups of patients.
  
  
  RESULTS
  In a cross section, endothelial cell density in group I / group II / group III decreased from 1,959+/-499 / 1,524+/-528 / 1,526+/-670 cells/mm(2)to 1,617+/-553 / 1,222+/-520 / 1,063+/-384 cells/mm(2) (P=0.06 / 0.04 / 0.005). Endothelial cell count was significantly higher in group I than in group II (P=0.048) and significantly higher in group II than in group III (P=0.01) at 24 months. In the linear regression model, cell count decreased in group I / group II / group III by 136+/-465 / 241+/-374 / 421+/-484 cells annually. In the exponential regression model, cell count decreased in group I / group II / group III by 2.9+/-28.0% / 11.2+/-21.8% / 19.3+/-29.4% annually. Cell loss was highly significantly lower in group I than in group II ( P<0.0001) and highly significantly lower in group II than in group III (P<0.0001).
  
  
  CONCLUSIONS
  Endothelial cell loss seems to be least pronounced after PK in keratoconus (2.9%), followed by Fuchs' dystrophy (11.2%) and bullous keratopathy (19.3%). These differences between diagnoses indicate migration of endothelial cells along a density gradient after PK.
authors.affiliation: Augenklinik mit Poliklinik der Universität Erlangen-Nürnberg, Schwabachanlage 6, Germany. achim.langenbucher@augen.imed.uni-erlangen.de
authors.forename: Achim
authors.initials: A
authors.lastname: Langenbucher
authors.forename: Berthold
authors.initials: B
authors.lastname: Seitz
authors.forename: Nhung X
authors.initials: NX
authors.lastname: Nguyen
authors.forename: Gottfried O H
authors.initials: GO
authors.lastname: Naumann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002452:Cell Count; D002470:Cell Survival; D002648:Child; D003316:Corneal Diseases / Q000175:diagnosis* / Q000601:surgery*; D004728:Endothelium, Corneal / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012044:Regression Analysis; D013997:Time Factors; D014019:Tissue Donors