Case Report: Double Intrastromal Corneal Ring Segment and Posterior Chamber Phakic Intraocular Lens Implantation.

Significance: Keratoconus can manifest asymmetrically, affecting binocularity and becoming a refractive problem that is sometimes complex to solve. We propose a therapeutic approach for correction of keratoconus based on parallel implantation of a second intrastromal corneal ring segment (ICRS).

Purpose: This study aimed to improve the refractive status of a patient affected with advanced bilateral keratoconus using implantation of a second ICRS and a phakic intraocular lens.

Case Report: A 44-year-old man came to our clinic requesting a refractive solution for his visual impairment. He had been diagnosed with bilateral severe keratoconus categorized by the Amsler-Krumeich classification scale as grade III (right eye) and grade II (left eye). He had previously undergone corneal cross-linking and implantation of ICRS (Intacs) in both eyes. Significant anisometropia was present between the eyes, and the patient also complained of poor quality of vision. We decided to implant a posterior chamber phakic collamer lens in his right eye and to insert a new ICRS (Keraring) deep and parallel to the previous one in his left eye. We aimed to prevent anisometropia in his right eye and to further regularize the affected cornea in his left eye. Refractive symmetry was achieved, and vision was optimized after surgery.

Conclusions: In a patient with keratoconus, refractive surgery should be performed from a bilateral perspective. Specific cases of keratoconus can be managed by parallel implantation of a second ICRS.