Intraoperative Peripheral Iridotomy for Endothelial Keratoplasty With a 22-Gauge Needle

Purpose: To describe the approach and advantages of a 22-gauge (22-G) needle for intraoperative peripheral iridotomy (PI) during endothelial keratoplasty. Methods: A superior approach is used to make an inferior PI. Intracameral lidocaine 1% and acetylcholine chloride 1% are injected intracamerally via a superior 1.1-mm paracentesis incision for pain control and miosis. The 22-G needle is bent near the hub with the bevel facing down. It is inserted through the paracentesis and passes through the pupil. As the needle-tip advances under the inferior iris, it is lifted periodically to identify its position until it reaches the ideal point for the PI. Counter-pressure is applied to the limbus at the exit point. The needle-tip is angled up and pushed through the iris and limbus so that the needle-shaft creates a standardized, patent, circular iridotomy (approximately 0.7 mm diameter and 0.4 mm 2 area). We compared the time needed for PI creation using intraocular scissors versus a 22-G needle by evaluating 10 surgical videos for each technique and statistically analyzing the timings using the Mann–Whitney U test and Bootstrapping. Results: The median time to produce a PI using a 22-G needle was 19 seconds (IQR: 14–24) compared with 85.5 seconds (IQR: 57–258) when using intraocular scissors ( P < 0.001, difference: 66.5 seconds, 95% CI, 33.5–238 seconds). Conclusions: A 22-G needle offers a safe, affordable, and efficient method using a standardized size diameter to produce an inferior PI during endothelial keratoplasty. Additional studies would assist to identify an ideal needle size across global populations.