Related Experiment Video
Updated: Aug 11, 2025

Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis
Published on: November 12, 2015
Intracorneal ring segment implantation in advanced Keratoconus
Philip W Dockery1,2, John S Parker2, Erik M Massenzio1
1Wills Eye Hospital, Philadelphia, USA.
Purpose:
To compare the clinical outcomes of intracorneal ring segment (ICRS) implantation in eyes with advanced vs. mild/moderate keratoconus (KCN).
Methods:
A retrospective analysis of 141 eyes of 111 patients with KCN who underwent ICRS implantation. Preoperative maximum keratometry (Kmax) was <57 diopters (D) in 70 eyes and >57 D in 71 eyes. Postoperatively, corrected distance visual acuity (CDVA), Kmax, and intraoperative and postoperative complications were assessed at 1 day, 1 month, and 1 year.
Results:
Corneas with a preoperative Kmax >57 D experienced greater reduction in axial curvature after ICRS implantation than corneas with a preoperative Kmax <57 D (7.0 D vs. 5.5 D, p=0.005) and gained more Snellen lines of CDVA (3 vs. 1, p<0.001) by 1 year postoperatively. The incidences of the most prevalent complications (explantation, extrusion, and infectious keratitis) did not differ significantly between the two groups (p=0.29, p=0.99, p=0.98).
Conclusions:
The visual and topographic effects of ICRS implantation are greater in eyes with more advanced KCN, with no increase in the incidence of the most common complications.

