Intrastromal Corneal Ring Segments: Outcomes and Complications

Intrastromal corneal ring segments (ICRSs) reshape the cornea by modifying its geometry, improving the patient’s corneal surface and leading to best-corrected vision in the majority of treated cases. Vision rehabilitation is faster than after other corneal surgical procedures, presenting fewer serious complications. It is well documented that ICRS implantation decreases the keratometric and refractive measures, reduces high order aberrations, and improves visual acuity. Success rates after ICRS implantation, as described in published articles, are high, depending on appropriate patient selection and adherence to suitable implantation nomograms. Moreover, ICRS implantation can be combined with other procedures, such as cross-linking. Regardless of being considered a safer and a more stable procedure, the following complications have been reported: incision and epithelial complications; decentration; asymmetry between the rings and problems related to tunnel creation; anterior chamber drilling; superficial ICRS positioning; migration; extrusion of the rings and corneal melting; deposits surrounding the ICRS; opacification/scars and neovascularization; infectious keratitis; and other complications (such as glare, halos and night reflexes, chronic eye pain, and patient dissatisfaction).