Implantation of intra-stromal corneal ring segments in severe keratoconus

Poster Details

First Author: S.Fukuoka JAPAN

Co Author(s):    R. Tano   T. Mano   N. Maeda        

Abstract Details

Purpose:

To investigate the feasibility of intra-stromal corneal ring segments (ICRS) for severe keratoconus. Femtosecond laser was used for channel creation to avoid the complications, and 3D OCT was adopted to conduct accurate topographic analysis.

Setting:

Retrospective case series, Tane Memorial Eye Hospital, Osaka, JAPAN

Methods:

Implantation of ICRS (Intacs® SK; Addition Technology, Inc., Des Plaines, U.S.A.) was performed in 6 eyes of 5 patients who had severe keratoconus with the steep keratometry (Ks) above 55 D. To making a channel for insertion of the ICRS, iFS Advanced Femtosecond Laser® (IntraLase, AMO) was used. Before and after the surgeries, Best spectacle corrected visual acuity (BSCVA) and VA with rigid gas permeable (RGP) contact lens were assessed, and the corneal topography was analyzed using three-dimensional anterior segment optical coherence tomography (SS-1000; Tomey Corporation, Japan).

Results:

In all cases, ICRS was inserted without any complications. With the mean follow-up of 14.2 months (range 12 to 18 months), mean BSCVA was significantly better postoperatively than preoperatively ( 0.69 logMAR +/- 0.34 [SD] to 0.32 +/- 0.09 logMAR, p=0.038). Although four eyes were RGP intolerance before surgery, all eyes became tolerant of RGP lenses all day. The mean VA with RGP lenses was -0.07+/- -0.07 logMAR postoperatively. The mean Ks was significantly improved from 60.5 +/- 3.7 D preoperatively to 55.6 +/- 3.7 D postoperatively (p=0.001). Fourier analysis of anterior corneal topography for 6mm diameter indicated both mean spherical and regular astigmatism components were significantly improved (56.7 +/- 3.3 to 52.4 +/- 2.6,p=0.0016 and 2.14 +/- 1.4 to 1.19 +/- 1.3, P=0.002, respectively).The mean asymmetry components and higher-order irregularity were not statistically different ( 5.38 +/- 4.0 to 4.67 +/- 3.3, P=0.15 and 0.55 +/- 0.3 to 0.5 +/- 0.26,P=0.37, respectively) .

Conclusions:

ICRS for severe keratoconus can be performed safely with femtosecond laser, and topographic improvements can be evaluated with OCT. Although longer follow-up is required, ICRS might be eligible to be performed in severe keratoconus before corneal transplantation because of the improvements in BSCVA and RGP lens fitting. FINANCIAL DISCLOSURE?: No