Statistical Analysis
tightness
REGRESSION
The outcome variables of this study are the incidence of GDs and rebubbling procedures. A GD was defined as any nonadherence of the graft noticeable on slit-lamp examination and AS-OCT imaging (Utrecht and Leuven: Zeiss Cirrus 5000, Zeiss Meditec, Oberkochen, Germany; Maastricht: Casia SS-1000, Tomey, Nagoya, Japan) at any time point within 3 months after surgery.Missing observations of CDVA and ECD were considered missing at random and imputed using multiple imputation. Missing measurements of subjects who developed a graft failure were considered missing not at random and not imputed. The number of imputations was equal to the maximum percentage of missing data plus 1. Two surgical recordings were missing, and the results were not imputed.Here, all cases were video analyzed irrespective of the randomization in the ADVISE trial. Consequences of the randomization (ie, prolonged overpressure of the eye) were entered as factors in the multivariable model. Subjects were post hoc assigned in 3 groups: completely attached graft, GD that did not require rebubbling, and GD that required rebubbling. Group differences were analyzed using a one-way ANOVA or Kruskal–Wallis test, as appropriate. Correction for multiple comparisons was performed using the Bonferroni correction. A 2-sided A multivariate multinomial regression analysis was performed to analyze the independent effect of intraoperative factors on the incidence of GD and rebubbling. Predictors included graft manipulation, graft shape, graft centering, gas-bubble size, method of peripheral iridectomy (laser vs. surgical), and overpressure duration. The regression analysis was adjusted for center, to account for differences between surgeons and number of surgeries, and donor age because this may influence scroll tightness.