Optimizing flange geometry with a 532-nm green laser for four-flanged scleral fixation: an experimental comparison with thermal cautery

SYNOPSIS: A 532-nm green laser was a feasible alternative to cautery, producing larger, flatter flanges at shorter heating lengths and supporting 1.0-mm laser heating for four-flanged scleral fixation. PURPOSE: To compare flange geometry produced with a 532-nm green laser versus thermal cautery in four-flanged scleral fixation and to identify practical heating lengths for 5-0 and 6-0 polypropylene sutures. SETTING: Dry laboratory. DESIGN: Bench-top experimental study. METHODS: Flanges were created on 5-0 and 6-0 polypropylene sutures using a 532-nm green laser (200 mW, 200 ms, single-shot mode) or handheld thermal cautery. Heating length, defined as the distance from the suture tip to the forceps, ranged from 0.5 to 3.0 mm in 0.5-mm increments. Flange diameter and height were measured microscopically, and shape was summarized by the diameter-to-height (D/H) ratio. RESULTS: Flange diameter and height increased with heating length for both devices. The laser produced larger diameters than cautery for 6-0 polypropylene at 0.5-1.5 mm (all P < .001) and for 5-0 polypropylene at 0.5-2.5 mm (P ≤ .023). At shorter heating lengths, the laser tended to produce flatter, saucer-shaped flanges with higher D/H ratios, whereas cautery often produced taller, mushroom-shaped profiles. Using guide-needle outer diameters as practical surrogate targets (30-gauge ≈ 300 μm for 6-0; 27-gauge ≈ 400 μm for 5-0), the shortest heating length at which mean flange diameter exceeded the target was 1.0 mm with laser and 1.5 mm with cautery for both suture sizes. CONCLUSIONS: Laser-assisted flange formation appears to be a feasible alternative to thermal cautery. In this dry-laboratory model, 1.0-mm laser heating and 1.5-mm cautery heating provided practical target flange dimensions while maintaining modest flange height.