Original Article

Penetrating keratoplasty in keratoconus: Effect of donor trephine sizing, based on posterior axial length and corneal topography, in postoperative refractive error - Original Article

  • Bora Yüksel
  • Aylin Çakmak
  • Hilal Bati
  • Engin Topaloğlu

Turk J Ophthalmol 2009;39(4):267-271

Purpose:

To achieve better postkeratoplasty refraction in keratoconus patients by using preoperative biometry and corneal topography.

Methods:

48 eyes of 46 patients who underwent penetrating keratoplasty for keratoconus from 1998 to 2005 were included in the study. The posterior axial length (PAL) group and the control group each consisted of 24 eyes. In the PAL group; PAL was measured prior to surgery. When the PAL was shorter than 19,0 mm, a 0,25 mm larger donor trephine was used. If PAL was longer than 21,0 mm, a same-size donor trephine was used. If it was between 19,0 – 21,0 mm, the midperipheral corneal topography was used to choose the trephine size. A Barron disposable punch was used to cut the donor corneas from the endothelial side.

Results:

Mean PAL was 19,59 mm (range 18,0 – 21,89) in PAL group. Mean best spectacle corrected visual acuity, spherical equivalent, keratometry, and keratometric astigmatism were 0,68, -1,25 D, 44,30 D and 4,01 D in PAL group and 0,67, -1,90 D, 45,10 D and 3,99 D in control group, respectively. In none of these parameters the differences were found to be statistically significant between the two groups.

Conclusion:

Although better outcomes were observed in the PAL group, this improvement was not statistically significant.

Keywords: Keratoplasty, keratoconus, midperipheral corneal topography, posterior axial length (PAL), trephine disparity