Assessment of intrastromal corneal ring segment position with anterior segment optical coherence tomography.

Background and objective: To examine the exact position of implanted Keraring (Mediphacos, Belo Horizonte, Brazil) segments by high-resolution anterior segment optical coherence tomography (AS-OCT).

Patients and methods: This study included 17 eyes of 13 patients with keratoconus who underwent uneventful intracorneal ring segment implantation with the aid of femtosecond laser. Eyes were evaluated by AS-OCT at the third postoperative month. Distance from the apex of the triangular cross-section of the ring segment to the anterior corneal surface and distances from two basal corners to the posterior corneal surface were measured.

Results: Distance from apex to anterior corneal surface (263.1 ± 42.9 μm) was significantly smaller than target depth calculated intraoperatively (356.9 ± 35.7 μm, P < .001). Distance between outer basal corner and posterior corneal surface was significantly greater than distance between inner basal corner and posterior corneal surface.

Conclusion: High-resolution AS-OCT is a rapid, convenient, and valuable technique in the follow-up of patients with implanted Keraring segments that may be helpful in predicting ring-related complications.