MAY 23, 2011
This small, retrospective case series investigates the feasibility of using the femtosecond laser for repeat penetrating keratoplasty (PK) in eyes that have undergone previous corneal graft and therefore have intracorneal scar tissue. The authors say their results support the feasibility of performing repeat PK with the femtosecond laser without major complications.
The study includes four patients who underwent repeat PK with the femtosecond laser for recurrent keratoconus, endothelial graft failure after conventional PK or low visual acuity after lamellar keratoplasty.
Repeat PK was performed with an Intralase FS TM System femtosecond laser (Abbott Medical Optics, Inc., Santa Ana, Calif.) in a ''top-hat'' or ''mushroom'' configuration. The procedure followed conventional PK in the two patients with keratoconus. Therefore, the second graft's diameter had to be larger than that of the first. In one patient, the new graft was applied within the first graft as a "transplant within a transplant." The authors were able to carry out femtosecond laser-assisted PK after Descemet stripping automated endothelial keratoplasty (DSAEK) outside the old graft diameter as well. Laser-assisted trephination took place in three of the four patients without adverse events, resulting in good wound healing independent of the positioning in relation to the first graft. Histological examination of the host corneas revealed straight cutting edges according to the programmed shape. The fourth case required manual completion of laser trephination because of tissue bridges.
BCVA in this series was lower than that of patients who have undergone conventional repeat keratoplasty, which the authors attribute to a high complication rate in eyes with abnormal conditions and vision-limiting factors, specifically uncontrolled IOP, postoperative trauma and irregular astigmatism. They conclude that the study's results demonstrate that repeat PK with femtosecond laser is technically a suitable method when the peripheral cornea is sufficiently clear.