Comparative Results in a Combined Procedure of Intrastromal Corneal Rings Implantation and Cross-linking in Patients with Keratoconus: A Retrospective Study

Abstract

Introduction: Corneal thinning disorders caused by keratoconus often lead to protrusion, irregular astigmatism, and even perforation. Keratoconus, like other corneal ectasia, does not have a known cause. Severe cases of keratoconus may require correction or restoration of tectonic integrity of the cornea by surgical means. Intracorneal ring segments are a new modality in the treatment of corneal ectactic disorders. A new technique of stopping the evolution of keratoconus and strengthening the cornea is combining techniques of intrastromal corneal ring implantation and corneal collagen cross-linking. The objective of the study is to compare the effectiveness of combined procedures: intrastromal corneal ring implantation followed by cross-linking, with cross-linking followed by intrastromal corneal ring implantation. Methods: The study comprised two groups of patients with different evolutionary stages of keratoconus, which met the eligibility criteria for intrastromal corneal ring segment implantation and corneal collagen cross-linking. Group 1 included patients (41 eyes) who underwent intrastromal corneal ring implantation followed by cross-linking and group 2 (30 eyes) included patients who underwent cross-linking first followed by intrastromal corneal ring implantation. Results: A decrease in Km values of about 1.5 D and refraction was observed in group 1, compared to a decrease in Km values of about 1 D and refraction in group 2. Recovery of visual acuity was higher in group 1 than group 2. Conclusions: The sequence of intrastromal corneal ring implantation followed by cross-linking proved to be more effective in reducing Km values, spherical equivalent and cylinder compared with cross-linking followed by intrastromal corneal ring implantation.