October 14, 2003
Nonmechanical Q-Switched Erbium:YAG Laser Trephination for Penetrating Keratoplasty
Experimental Study on Human Donor Corneas
Arch Ophthalmol. 2003;121:1415-1422.
Thirty human corneoscleral donor buttons unsuitable for transplantation were placed in an artificial chamber on an automated rotation device. Corneas were trephined with a Q-switched Er:YAG laser (wavelength, 2.94 µm; pulse duration, 400 nanoseconds) along (donor and recipient) aluminum silicate (ceramic) open masks. A spot diameter of 0.65 mm, energy setting of 50 mJ/pulse, and repetition rate of 5 Hz were used. Corneal thermal damage and cut regularity were quantitatively assessed in 24 corneas processed for light microscopy and by transmission and scanning electron microscopy.The stromal thermal damage was the highest (mean [SD], 8.0 [2.7] µm) at a 150-µm cut depth and decreased downward. Cut regularity was very good and did not significantly differ between donors and recipients. Scanning electron microscopy confirmed that the cuts were highly regular; transmission electron microscopy revealed 2 distinctive subzones within the stromal thermal damage zone.Conclusions Thermal damage induced by Q-switched Er:YAG nonmechanical corneal trephination was low, and the regularity of the cuts was very good.
Posted by mehdi khanlari at October 14, 2003 10:13 PM