Preoperatively , the mean axial length was 23.36 mm 1.55 ( SD ) ( range 21.01 to 29.46 mm ) in the CTR group and 23.37 1.70 mm ( range 21.14 to 28.84 mm ) in the control group and the mean ACD was 3.06 0.45 mm ( range 2.25 to 4.16 mm ) and 3.03 0.47 mm ( range 2.18 to 4.10 mm ) , respectively .