Resumen de Wavefront aberrations prior to and post Intrastromal Corneal Ring Segment implantation in keratoconus

Victor Paes Simoceli, Leonardo Torquetti, Rosângela A. Simoceli, Paulo Ferrara

• PURPOSE: To describe the wavefront changes induced by the implantation of Ferrara intrastromal corneal ring segments (ICRS) in keratoconus.

  METHODS: ICRS were implanted in 96 eyes of 92 patients with keratoconus grade I, II and III. Ocular aberrations were examined using the Nidek OPD scan wavefront aberrometer.

  RESULTS: !ere was an improvement in uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) for all grades of keratoconus. For grade I the mean UDVA improved from 0.94 ± 0.38 to 0.65 ± 0.38 LogMAR (p<0.001) and CDVA from 0.35 ± 0.17 to 0.19 ± 0.16 (p<0.001). In keratoconus grade II the mean UDVA improved from 1.15 ± 0.35 to 0.67 ± 0.36 LogMAR (p < 0.001) and CDVA from 0.50 ± 0.22 to 0.25 ± 0.18 (p<0.001). In grade III the mean UDVA improved from 1.28 ± 0.28 to 0.92 ± 0.45 LogMAR (p<0.001) and CDVA from 0.65 ± 0.27 to 0.46 ± 0.25 (p<0.001). RMS at 3mm improved (p<0.01) in grades I and II but not in grade III (p=0.75) while RMS at 5mm improved in all groups. However, this was only statistically signi"cant in grade I (p<0.001).

  Primary Coma statistically decreased in patients with grade I and II (p<0.01) but not in grade III (p=0.10). Negative spherical aberration increased in all groups. All other peripheral aberrations statistically increased, except for trefoil in grade I that decreased but this had no statistical signi"cance (p=0.73).

  CONCLUSION: Ferrara ICRS improved CDVA and UDVA in all groups, decreasing total aberrations, coma and tilt, while increasing other HOAs