Femtosecond Laser–Assisted Stromal Lenticule Addition Keratoplasty for the Treatment of Advanced Keratoconus: A Preliminary Study

To propose a new keratoconus classification/staging system that utilises current tomographic data and better reflects the anatomical and functional changes seen in keratoconus.

To prospectively study the feasibility of femtosecond lenticule extraction (FLE), a new method of refractive correction. Department of Ophthalmology, Philipps University of Marburg and Helios Clinic, Erfurt, Germany. A flap and a lenticule of intrastromal corneal tissue were simultaneously cut with a VisuMax femtosecond laser system. Next, the lenticule was manually removed and the flap repositioned. The target refraction in all cases was -0.75 diopter (D). All 10 myopic eyes in the initial treatment group completed the final 6-month follow-up. The mean patient age was 39 years. The mean spherical equivalent (SE) was -4.73 +/- 1.48 (SD) preoperatively and -0.33 +/- 0.61 D 6 months postoperatively. Ninety percent of eyes were within +/-1.00 D and 40% were within +/-0.50 D of the intended correction. No eye lost 2 or more Snellen lines. Corneal topography showed large, prolate optical zones. Aberrometry showed no significant induction of higher-order aberrations. On a standardized questionnaire, all patients said they were very satisfied with the results. Preliminary results indicate that FLEx [corrected] is a promising new corneal refractive procedure to correct myopia.

To assess the effectiveness of ultraviolet A (UVA) irradiation-induced collagen cross-linking (CCL) on keratoconus (KC) progression. A patient with bilateral, progressive KC underwent UVA irradiation (3 mW/cm for 30 minutes) after topical 0.1% riboflavin drops over a deepithelialized cornea. Twelve months later, a topography-guided penetrating keratoplasty (PRK; wavelight 400 Hz Eye-Q excimer) was performed in 1 eye for a refractive error of -3.50 -4.00 x 155 by using an attempted treatment of -2.50 -3.00 x 155. At all postoperative follow-up visits to 18 months, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), pachymetry, and topography were performed. In the treated left eye, the UCVA after the UVA CCL improved from 20/100 to 20/80, and the BSCVA improved from 20/50 to 20/40. Eighteen months after the topography-guided PRK, the UCVA was 20/20, and the BSCVA was 20/15, with a refractive error of Plano -0.50 x 150. The cornea was clear, and the endothelial cell count remained unchanged. The untreated right mate eye continued to progress during the same period. The significant clinical improvement and the apparent stability of more than a year after UVA CCL, and subsequent PRK compared with the untreated mate eye, seems to validate this treatment approach for KC. An adjusted nomogram may be considered in the ablation of cross-linked cornea tissue to avoid overcorrections.