Modulation of intrastromal ring position according to postoperative outcome in asymmetric keratoconus using femtosecond laser: a new technique

Session Details

Session Title: Photoablation, Cross-Linking and Intracorneal Ring Segment

Session Date/Time: Monday 07/09/2015 | 08:00-10:30

Paper Time: 08:42

Venue: Room 16

First Author: : L.Izquierdo Jr PERU

Co Author(s): :    M. Henriquez   M. Orozco   A. Rodriguez              

Abstract Details

Purpose:

To evaluate the visual and refractive outcome after postoperative changes in the intrastromal corneal ring segment (ICRS) position in patients with refractive postoperative surprise, using a new technique that implies an amplification of the length of the tunnel assisted by femtosecond laser.

Setting:

Oftalmosalud Instituto de Ojos, Lima, Peru.

Methods:

This was a prospective case control study between June 2014 and march 2015 including eyes after ICRS due asymmetric keratoconus, that after 1 month had best corrected visual acuity of 0.3 or worst and/or residual astigmatism bigger than 1.5 D. A 50% longer intrastromal tunnel that supposed was performed in all eyes using femtosecond laser (Ziemer Z8), ICRS was implanted according to Ferrara nomogram. After one month of the ICRS insertion, if visual acuity was worst than 0.3 LogMAR and/or cylinder greater than 1.5 Diopters (D) the ICRS was moved through the initial intrastromal channel 90 degrees forward.

Results:

A 50% longer tunnel was created using femtosecond laser to implant an ICRS in asymmetric keratoconus in 27 patients, 11 patients had postoperative astigmatism worst than 1.5D and/or BCVA worst than 0.3 LogMAR at 1 month. After ICRS mobilization mean maximum keratometry change from 44.4 um to 43.5 um (p = 0.04). Mean uncorrected visual acuity (UCVA) change from 0.4 LogMAR um to 0.10 (p = 0.05) and mean best-corrected visual acuity (BCVA) change from 0.3 LogMAR to 0.07 LogMAR (p =0.06). Coma aberration improved between pre and post ICRS mobilization (p=0.05). There were not complications reported in this group of patients.

Conclusions:

Sequential mobilization of the ICRS into the previous longer intrastromal channel created in patients with asymmetric keratoconus is an effective technique to improve the final visual acuity and refractive error.

Financial Interest:

NONE