The effect of vernal keratoconjunctivitis on clinical outcomes of penetrating keratoplasty for keratoconus

Abstract

Background: Although good visual results and low complication rates are commonly reported following penetrating keratoplasty (PKP) in eyes with keratoconus, the outcome of PKP in eyes with keratoconus and concomitant vernal keratoconjunctivitis (VKC) has not been well documented. We performed a study to compare the outcome and relative risk factors of PKP for keratoconus with and withoutVKC.

Methods: Review of the medical records of all patients who underwent PKP for keratoconus at a university-affiliated hospital in Izmir,Turkey, from Nov. 1, 1991, to Jan. 31, 2002. Only eyes that had been followed for at least 18 months postoperatively were included in the study. Twenty-three eyes of 19 patients (14 males and 5 females) had keratoconus with VKC, and 65 eyes of 57 patients (33 males and 24 females) had keratoconus alone. We compared clinical outcomes and complications between the two groups.

Results: The mean length of follow-up was 34.0 months (standard deviation [SD] 16.3 months) (range 18-67 months) in the eyes with comitant VKC and 41.0 (SD 19.8) months (range 18-98 months) in the eyes with keratoconus alone. During the follow-up period, 2.35 (SD 1.90) suture-removal sessions for loosened sutures were performed in the eyes with VKC, compared with 1.34 (SD 1.69) sessions in the eyes with keratoconus alone (p = 0.016). Steroid-induced glaucoma developed in two eyes (8.7%) in theVKC group and in three eyes (4.6%) in the keratoconus-alone group (p = 0.603); the rates of steroid-induced cataract were four (17.4%) and two (3.1%) respectively (p = 0.038). The average final best-corrected visual acuity was 20/22 (range 20/50 to 20/20) in the eyes with VKC and 20/23 (range 20/60 to 20/20) in the eyes with keratoconus alone.

Interpretation: The clinical outcome of PKP in eyes with keratoconus and VKC is comparable to that in eyes with keratoconus alone. However, because complications such as prematurely loosened sutures and steroid-induced cataract are more common in the coexistence of VKC, closer monitoring is necessary in these cases.