To simplify and enhance safety in the generation of a stabilizing intracorneal scar by circular keratotomy (CKT). A femtosecond laser was used to perform individually sized intraparenchymal cuts.

As equipped, the Ziemer Z6 femto-second laser cuts a 400-µm-deep incision with a diameter of 7.0 mm around the optical axis. The epithelium, Bowmann's membrane, the internal borders of Descemet's membrane, and the endothelium are not affected.

The 3-, 6-, and 12-month postoperative values were compared with the 1-month postoperative keratometric readings and astigmatism. The preoperative best corrected visual acuity (BCVA) with glasses was compared with the values found at the same time points as noted above.

Statistical evaluation indicated that keratometry within ±1.5D remained in 96.6, 93.1, and 96.6% of cases at the 3-, 6-, and 12-month time points respectively.

Astigmatism was stable at the same time points in 100, 95.8, and 92.3%.

The BCVA improved in 12 cases throughout the first post-operative year (48%, n = 25); however, 11 cases did not change (44%) and 2 cases lost at least one line (8.0%).

Femto CKT halts the progression of keratoconus for at least 1 year in 96.6% of cases. This treatment provides keratometric and refractive stability for over 1 year. This result, in conjunction with the significant improvement in BCVA, demonstrates the potential of this method for patients with stage I and II keratoconus.

Krumeich JH, Hirnschall N, Breyer D, Laufer F. Femto Circular Keratotomy to Halt the Progression of Keratoconus I and II. Int J Kerat Ect Cor Dis 2016;5(3):109-113.