J Ruckhofer1, M D Twa, D J Schanzlin. 1. Shiley Eye Center, University of California, San Diego, California, USA. j.ruckhofer@lks.at
Abstract
PURPOSE: To report the frequency, location, and severity of biomicroscopically evident intrastromal deposits that may accumulate in the lamellar channel after implantation of Intacs corneal ring segments. SETTING: United States Food and Drug Administration multicenter clinical trial conducted at 10 sites. METHODS: Two-year follow-up data from a phase III clinical trial (N = 359) were reviewed. Examiners at 10 study sites described the location and severity (density) of deposits, grading severity on a standardized scale from absent (0) to severe (4). At 24 months, the incidence of deposits was 74% overall and 61%, 73%, and 89% with the 0.25, 0.30, and 0.35 mm Intacs, respectively (P <.001). The incidence increased sharply at first and more slowly after 6 months. RESULTS: At 12 months, deposits were located along the inner curvature of the segments in 47% of patients, along the outer curvature in 5%, along both inner and outer curvatures in 38%, and anterior to the segments in 10%. The severity of the deposits increased with segment thickness (P <.001 at 6, 12, and 24 months). CONCLUSIONS: Lamellar channel deposits occurred frequently after Intacs implantation. The incidence and density of deposits increased with segment thickness and duration of implantation. The presence of this material did not result in alteration of the optical performance of Intacs or anatomical or physiological corneal deterioration.
PURPOSE: To report the frequency, location, and severity of biomicroscopically evident intrastromal deposits that may accumulate in the lamellar channel after implantation of Intacs corneal ring segments. SETTING: United States Food and Drug Administration multicenter clinical trial conducted at 10 sites. METHODS: Two-year follow-up data from a phase III clinical trial (N = 359) were reviewed. Examiners at 10 study sites described the location and severity (density) of deposits, grading severity on a standardized scale from absent (0) to severe (4). At 24 months, the incidence of deposits was 74% overall and 61%, 73%, and 89% with the 0.25, 0.30, and 0.35 mm Intacs, respectively (P <.001). The incidence increased sharply at first and more slowly after 6 months. RESULTS: At 12 months, deposits were located along the inner curvature of the segments in 47% of patients, along the outer curvature in 5%, along both inner and outer curvatures in 38%, and anterior to the segments in 10%. The severity of the deposits increased with segment thickness (P <.001 at 6, 12, and 24 months). CONCLUSIONS:Lamellar channel deposits occurred frequently after Intacs implantation. The incidence and density of deposits increased with segment thickness and duration of implantation. The presence of this material did not result in alteration of the optical performance of Intacs or anatomical or physiological corneal deterioration.