PENETRATING KERATOPLASTY FOR KERATOCONUS: VISUAL OUTCOMES AND COMPLICATIONS

Purpose: To determine the long-term visual outcomes and complications of penetrating keratoplasty (PK) performed for keratoconus. Methods: Hospital records of patients with keratoconus who underwent PK at the Ophthalmology Center of Shaheed Sadoughi, Yazd, Iran, during 1992-2003 were reviewed. We studied records of 84 PK procedures in 72 keratoconus patients. Data including best corrected visual acuity (BCVA), type of correction, type of suturing, incidence of rejection, keratometry, and postoperative complications were reviewed and analyzed at 12 and 18 months. Results: Best corrected visual acuity (BCVA) improved from 20/40 at month 12 to 20/30 at month 18. (P< 0.0001) Mean spherical refraction was -4.81 diopter (D) at 12 month. BCVA was 20/40 or better in 71.4% of the eyes at last follow-up and 65.5% of the eyes were corrected by spectacles. Mean preoperative corneal power by keratometry was more than 52 D in 78.8% of eyes and mean postoperative corneal power was 46 ± 2.5 D at the end of the first week. The only significant predictor of post operative astigmatism was donor-recipient disparity. Allograft rejection was seen in 26.1% of cases and there were two graft failures due to allograft reaction. Overall 19% of cases required keratorefractive surgery. At last follow-up, spherical equivalent was -2.50 ± 1.15 D, corneal astigmatism was 3.8 ± 1.9 D, and BCVA was 0.26 ± 0.14 Log MAR. Mean spherical equivalent of refractive error was better with 0.25 mm donor-recipient difference (-3.1 ± 2.5 D) in comparison to 0.50 mm difference (-4.2 ± 2.8 D). (P< 0.001) Conclusions: Penetrating keratoplasty is a good treatment option for keratoconus. Our data demonstrated that the majority of patients require optical correction for functional VA after keratoplasty.