Axial length is a major determinant of ocular refractive power that has not been well established for
keratoconus eyes. The purpose of this study was to establish the mean and range of axial length among both
keratoconus eyes with no previous surgery and postkeratoplasty
keratoconus eyes, and to determine if there is a significant reduction of axial length following variations in surgical techniques in
penetrating keratoplasty. The axial length of 157
keratoconus eyes with no previous surgery was measured using applanation ultrasonography. The mean axial length measurement was 24.39 (+/- 1.13 mm), with a range of 21.82-28.69 mm. The axial length of 66 postkeratoplasty
keratoconus eyes was similarly measured. The mean axial length measurement was 24.10 (+/- 1.22 mm), with a range of 21.83-26.87 mm. These values are not significantly different from the axial length mean and range found among emmetropic eyes. A significant shortening of the axial length (F = 5.2, p = 0.04) was obtained in the postoperative
penetrating keratoplasty eye if the donor trephine was 0.3 mm smaller in diameter than the recipient trephine. The axial length of individual
keratoconus eyes is a major factor in determining postoperative
refractive error. It therefore becomes important when considering variations in
surgical procedures to reduce postoperative
myopia.