Measurement of the surface temperature of the cornea during ArF excimer laser ablation by thermal radiometry with a 15-nanosecond time response

Background and Objective: The purpose of this work was to develop a temperature measurement system with a nanosecond time response to monitor the transient temperature of the corneal surface during laser refractive surgery. Materials and Methods: Thermal radiation from the surface of the porcine cornea during ArF excimer laser irradiation was measured using a photovoltaic HgCdTe detector with a response bandwidth of 150 MHz. Results: Maximum thermal radiation occurred at 31 ± 4 nanoseconds, which was longer than the time response of the measurement system. The temperature derived from the detected signal reached over 100°C at a fluence of 80 mJ/cm², which was the ablation threshold, and reached 240°C at a fluence of 180 mJ/cm². Conclusion: The present system of temperature measurement with a time response of 15.7 nanoseconds revealed that the transient surface temperature of the cornea during ablation is much higher than that previously reported.