To evaluate the short-term outcomes of femtosecond laser-assisted implantation of keraring 340 degrees in patients with keratoconus

In this prospective nonrandomized case series, all cases underwent keraring 340 degrees implantation after tunnel creation by femtosecond laser. Uncorrected and best spectacle-corrected distant visual acuity (UCVA and BSCVA), sphere (S), cylinder (C) and manifest refraction spherical equivalent (MRSE), mean keratometry (Km), steep keratometry (Ks), and flat keratometry (Kf) were evaluated before surgery and 1, 3 and 6 months postoperatively

Eighteen eyes of 17 patients were included. Follow-up period after surgery was one to six months (mean 4.33±2.03). UCVA improved from 0.95± 0.33 LogMAR to 0.53± 0.35 (P= 0.001) and BCVA from 0.39±0.22 to 0.26± 0.21 LogMAR (P= 0.09). Mean sphere decreased from -5.08± 3.74 diopter (D) to -1.67± 2.59 D, mean cylinder from -5.83± 2.02 D to -2.72± 1.81D, and mean MRSE from -8.03± 3.88 D to -3.01±2.82 D (P< 0.001). Mean Ks decreased from 54.86± 4.28 D to 49.13± 3.83 D (P< 0.001), mean Kf from 47.83± 3.27 D to 45.67± 3.46 D (P= 0.001), and mean Km decreased from 51.43± 3.59 D to 47.42± 3.59 D (P< 0.001). All patients with preoperative Km more than 55 D had worsened BCVA

Implantation of keraring 340 degrees using femtosecond laser improved the visual, refractive, and topographic parameters in keratoconic patients. Patients with severe KC (Km more than 55 D) are not good candidates for this type of ICRS according to our findings