Thermal effect on corneal incisions with different phacoemulsification ultrasonic tips

Purpose: To evaluate the thermal effects of 3 phacoemulsification ultrasound (US) tips (standard, MicroTip(TM), and Mackool(TM)) on the corneal incision based on the tips position. Setting: Department of Ophthalmology, Tokyo Dental College, Tokyo, Japan. Methods: Thermal changes were recorded with an infrared thermal video during phacoemulsification in 18 porcine eyes. The 3 US tips were placed in 3 positions (primary, roofing, and flanking) in the corneal incision, and the resultant temperature changes were recorded. Results: With the 3 US tips in the primary position, the temperature remained under 36°C. When the tips were the roofing position, a marked temperature increase (51.4°C) was observed with the standard tip; with the MicroTip, a temperature increase occurred but was lower than with the standard tip; with the Mackool tip the temperature remained stable. The temperature around the incision site increased with all tips when they were moved toward the corner of the incision, which resulted in direct contact with the silicone sleeve. This change was most obvious with the standard tip (temperature 51.5°C), and a wound burn was observed. With the MicroTip, the temperature increase was moderate (44.2°C) and the wound burn area was smaller. With the Mackool tip, the temperature increased the least (42.1°C). Conclusion: The position of the US tips resulted in a temperature increase in the incision area and caused wound burn. Newly developed US tips could minimize this complication.