Femtosecond laser intracorneal ring segment implantation based on a nomogram modification in type 1 and type 2 ectasia.

Aims: The aim of the study was to evaluate the refractive, topometric and aberrometric changes in corneas with keratoconus treated with femtosecond laser intracorneal ring segment (ICRS) implantation following a proposed modified nomogram. Settings and design: This is a retrospective, consecutive case series. Materials and methods: ICRS implantation using the new proposed nomogram was performed in 10 eyes of seven patients with type 1 and type 2 keratoconus. Corneal tunnels were created using femtosecond laser, and KeraRings were inserted in all eyes. All cases were followed up every 3 months for 6 months using the Pentacam Phoenix system. Statistical analysis: All analyses were performed with SPSS for windows 2007. Results: None of our patients developed complications related to ring placement, such as migration, extrusion or infection. In this limited case series an improvement was seen in uncorrected visual acuity (P ≤ 0.05), best spectacle corrected visual acuity (P ≤ 0.001) and refraction at 6 months (P < 0.001). Keratometric readings improved (P < 0.001), with flattening of the cornea. Corneal aberrations showed significant reduction when analysed by Zernike (P < 0.001) and Fourier analysis (P ≤ 0.001). Corneal asphericity (Q value) also showed improvement (P < 0.05). Conclusion: Femtolaser ICRS implantation using the proposed modified nomogram showed promising results in improving refraction, visual acuity, corneal topography and aberrations in patients with keratoconus. [ABSTRACT FROM AUTHOR]