DIAMOND-TIP VERSUS BLUNT-TIP CALIPER ENLARGEMENT OF CLEAR CORNEAL INCISIONS

Purpose: To assess corneal trauma after clear corneal incision (CCI) e nlargement with a diamond-tip versus a blunt-tip caliper, Setting: Uni versity of Vienna, Austria. Methods: Human bulbi obtained from the eye bank of the University of Vienna had a 3.0 mm single-plane CCI enlarg ed to 5.0 mm using either a diamond-tip or a blunt-tip adjustable cali per. During the process, eye pressure was kept between 22 and 25 mm Hg by infusing balanced salt solution using an anterior chamber maintain er. Light, scanning electron, and transmission electron microscopy wer e performed according to standard procedures. Results: Incisions enlar ged with the diamond-tip caliper were well-defined and allowed good cl osure of the wound lips. In contrast, the blunt-tip caliper produced w idened, drumstick-shaped recesses at the lateral ends of the incisions . Adjacent to these recesses, the collagen lamellae were severely disl ocated and torn. Conclusion: Cutting the corneal tissue with diamond t ips caused less tissue damage than expanding it with blunt tips. It wa s not possible to temporarily widen incisions using a blunt-tip calipe r without significantly intensifying tissue damage.