In a 180-day follow-up , the AMT group exhibited mean central corneal thickness ( CCT ) , 899.4 m preoperatively and 1122.5 m postoperatively ( p < 0.001 ) ; mean epithelial thickness ( ET ) , 156.4 m preoperatively and 247.8 m postoperatively ( p < 0.001 ) ; and mean stromal thickness ( ST ) , 742.9 m preoperatively and 826.3 m postoperatively ( p = 0.005 ) .