Thermal Profile of Pulse Precision Capsulotomy: In Vivo and In Vitro Infrared Thermography Study

PURPOSE: This study aimed to elucidate the thermal safety of precision pulse capsulotomy (PPC) via in vivo and in vitro evaluation of the thermal profile using infrared thermography. METHODS: This prospective observational study enrolled 15 eyes from 15 participants who underwent cataract surgery using the Zepto PPC. All patients underwent temperature measurements of the incision site and the entire cornea using an infrared thermographer during the capsulotomy procedure. To accurately analyze the temperature change of the Zepto PPC, infrared thermography was performed with the Zepto handpiece while exposed to air and then in porcine eyes. Moreover, in each case, the difference in temperature change according to the use of an ophthalmic viscosurgical device (OVD) was also checked to determine the temperature buffering effect. RESULTS: In the clinical evaluations, the mean temperature elevation around the corneal incision and time duration from baseline to peak temperature during the Zepto capsulotomy were 4.0°C ± 1.9°C and 4.43 ± 1.26 seconds, respectively, with a mean peak temperature of 32.6°C ± 2.0°C. The mean peak temperature and rise time of the naïve Zepto nitinol ring, as measured from the bottom side, were 109.0°C ± 22.9°C and 43.40 ± 11.06 seconds in the experimental procedures, respectively. In the porcine eyes, the mean elevation of temperature and rise time of the Zepto nitinol ring were 6.2°C ± 1.6°C and 11.67 ± 2.08 seconds with the use of OVDs, and 10.5°C ± 3.3°C and 14.00 ± 3.61 seconds without OVDs, respectively. CONCLUSIONS: Zepto PPC has the potential to generate extremely high thermal energy, according to an in vitro study. However, the temperature rise of the Zepto capsulotomy can be minimized by using OVDs.