Changes in corneal epithelial barrier function after penetrating keratoplasty

Purpose. To investigate changes in corneal epithelial barrier function after penetrating keratoplasty Methods. One-hundred nine post keratoplasty eyes with a mear postkeratoplasty period of 17.0 months were examined for corneal epithelial barrier function using fluorophotometry (Kowa Co., FL-500). Specular microscopy for the corneal epithelium, vital stain tests were also performed. Results. The mean fluorescein uptake value was 300.4±69.1 ng/ml (mean±SE), which was about 8 times higher than normal. Patients with diabetes mellitus, and whose eyes having conjunctival invasion preoperatively demonstarted higher values. Significant differences in the values were noted among different causative diseases (F=0.0036). Eyes with keratoconus showed lower value (30.5±6.12 ng/ml) compared with either corneal scar (100.2± 11.6 ng/ml), or bullous keratopathy (105.4±21.4 ng/ml). Barrier function had significant correlations wth patients' age (P=0.0001), fluorescein staining score (P=0.032), Schimer's test (P=0.0036), and tear clearance test (P=0.018), but not with postkeratoplasty period and epithelial morphology. Conclusions. Corneal epithelial barrier function after penetrating keratoplasty is highly impaired. The function is determined by multifactors, including causative diseases for keratoplasty and tear functions.