Forty patients who maintained a clear cornea for at least 20 years after receiving penetrating keratoplasty (PKP) were evaluated to determine favorable prognostic factors of PKP.

Among 78 patients who underwent PKP before 1986, 40 patients continue to maintain clear corneas in 2008. Demographic features of the recipients and the donors, along with underlying diseases causing blindness, the trephine size of the donor and recipient corneas, suturing methods, preoperative and postoperative visual acuity, and cause of death of the donors were evaluated retrospectively. The criteria of clear cornea maintenance was based on patient medical records.

Among those patients maintaining clear corneas 20 years after PKP, females outnumbered male patients by 25 patients more. Patients who underwent the operation in their twenties had the highest success rates. The most common condition necessitating PKP was keratoconus, followed by traumatic corneal opacity and herpes keratitis in descending order of frequency. Female donors exceeded male donors in number. Most donors were aged 60 years or older, and the most common cause of donor death was accident. The most frequently used trephine size was 7.0 mm for the recipient and 7.5 mm for the donor, and continuous suture was used more often than interrupted suture. Patients who preserved clear corneas for at least 20 years after PKP displayed a preoperative visual acuity of counting fingers at 30 cm, which improved to 0.11 after the operation.

We propose favorable prognostic factors of PKP based on our analysis of the characteristic features of patients who maintained clear corneas for at least 20 years after receiving a penetrating keratoplasty.