Femtosecond laser-assisted intrastromal relaxing incisions following penetrating keratoplasty

Session Details

Session Title: Challenge of Astigmatism Correction

Session Date/Time: Sunday 14/09/2014 | 17:00-18:30

Paper Time: 17:24

Venue: Capital Hall A

First Author: : O.Wetterstrand FINLAND

Co Author(s): :    J. Holopainen   K. Krootila           

Abstract Details

Purpose:

Femtosecond (FS)-assisted intrastromal relaxing incisions (FS-ISRI) are an effective option to treat high levels of astigmatism following penetrating keratoplasty (PK). Here we have retrospectively evaluated the efficacy of FS-ISRI and correlated the efficacy with the posterior depth of the incision.

Setting:

Helsinki University Eye Hospital, Helsinki, Finland

Methods:

Twenty eyes of 20 patients were treated for regular astigmatism after PK. Regarding the refractive status all eyes had stable refraction and sutures had been removed previously. Corneal thickness was measured prior to FS-ISRI with ultrasound pachymetry to calculate the incisional depth. FS-laser assisted paired arcuate incisions were made inside the graft stroma to an anterior depth of 90 µm thus preserving the epithelium. Ten eyes were operated with a 125 µm marginal of the posterior intact cornea and 10 eyes with a 90 % corneal depth (i.e. 10% of the posterior corneal depth was left unoperated). Clinical follow-up consisted of biomicroscopy, intraocular pressure measurement, fundus examination and topographic evaluation using anterior segment OCT (Tomey SS-1000 Casia) at one and three months. Corneal thickness and postoperative depth of incisions was measured from OCT scans.

Results:

Best corrected visual acuity (BCVA) improved from 0.53 ± 0.21 to 0.30 ± 0.14 logMAR (p < 0.05) in the 90 % group and remained constant in the 125 µm group. Refractive cylinder decreased in the 90 % group 27.4 ± 34.2 % but remained unchanged in the 125 µm group. Topographic anterior cylinder decreased by 38.5 ± 40.0 % and 15.9 ± 16.8 % respectively (p < 0.05). The smaller the posterior intact corneal margin was, the higher the surgically induced astigmatism was (SIA, p < 0.05). One patient had a graft rejection episode that was successfully treated.

Conclusions:

FS-laser assisted intrastromal relaxing incisions are effective treatment for post-PK astigmatism. The efficacy seems to improve with increasing the posterior depth of the arcuate incisions.

Financial Interest:

NONE