Additional Intrastromal Corneal Ring Segments in Keratoconus

Purpose: To evaluate the outcome of additional KeraRing (Mediphacos, Belo Horizonte, Brazil) implantation in patients with keratoconus with previously implanted INTACS (Addition Technology Inc, Fremont, CA) segments. Methods: The KeraRing was implanted in 5 eyes of 3 patients with keratoconus without removal of previous intrastromal corneal ring segments. Tunnels were created manually Snellen uncorrected distance visual acuity (UDVA), corrected distance visual acuity, refractive and keratometric values, and higher-order aberrations were recorded before and after KeraRing implantation. Results: UDVA, corrected distance visual acuity, subjective refraction, and keratometric values were improved in 4/5 of cases and remained stable during a median follow-up of 36 months. UDVA improved from 20/200 and 20/100 to 20/100 and 20/40 in the right and left eyes of patient 1, respectively, and from 20/200 to 20/40 in both eyes of patient 2. The reduction in mean keratometric value was 2.1 and 4.4 D in the right and left eyes of patient 1, and 1.4 and 1.9 D in the right and left eyes of patient 2, respectively. In patient 3, UDVA (20/100) and mean keratometric value (52.4) remained unchanged after second intrastromal corneal ring segment implantation. Total higher-order aberrations were improved in all cases. No intraoperative or postoperative complication was observed. However, one of the cases reported glare under scotopic conditions. Conclusions: KeraRing implantation in properly selected eyes with previously implanted INTACS could enhance final visual and refractive outcomes.