Unusual secondary displacement of Intacs segments--superimposition of distal ends.

Unusual Secondary Displacement of Intacs Segments—Superimposition of Distal Ends We report a case of unusual secondary displacement of intrastromal corneal ring segments (Intacs; Addition Technology, Des Plaines, Illinois) away from the incision to the extent that the inferior ends overlapped in the tunnel. A 57-year-old man presented with unilateral keratoconus in the left eye with recent contact lens intolerance. Although biomicroscopic examination of the left eye showed a Fleischer ring with no corneal opacity, the right eye was normal. Corneal topography demonstrated moderate keratoconus in the left eye and forme fruste keratoconus in the right eye. Uncorrected distance visual acuity (UDVA) in the left eye was 0.1 (Snellen decimal notation) and corrected distance visual acuity (CDVA) was 0.2 with refraction of 11.00 3.50 107°; UDVA in the right eye was 0.1 and CDVA was 0.8 with refraction of 1.50 2.75 80°. A two-segment, symmetric, mechanical Intacs implantation using 0.45-mm segments was performed on the left eye. Radial incision was placed on the 30° axis with a depth of 380 μm (peripheral corneal thickness, 520 μm). Postoperative examination on day 6 was normal with the two segments in perfect position and an improvement in keratometry from preoperative values of 50.00 29°/45.30 119° (Kmax/ Kmin) to 44.70 42°/40.60 132°. At 1-month follow-up, both segments were noted to have rotated away from the incision and the distal ends of the segments had become superimposed (Figs A and C). However, keratometry improved to 43.70 9°/38.60 99° and refraction to 5.50 2.50 92° with CDVA of 0.3. Because the patient was satisfi ed with the visual improvement, we decided to follow him without any surgical adjustment. At 3, 7, and 12 months, the anatomical aspect remained stable with no additional rotation of the segments; CDVA improved to 0.7 at 12 months with refraction of 7.00 1.25 100° (keratometry 42.00 23°/39.40 113°) (Fig B). The right eye demonstrated no progression of keratoconus with stable refraction and keratometry throughout 12-month follow-up. The natural tendency of segment migration is towards the incision.1 A superfi cial implantation2 or distance 1 mm between the incision and proximal