Optimizing Measurement Parameters for Ocular Surface Temperature Assessment Using ResearchIR Software

Purpose: This prospective, observational clinical study aimed to establish standardized ocular surface temperature (OST) measurement protocols using infrared thermography (IRT) to improve consistency, reliability, and translational applicability. Methods: OST was assessed in seven healthy adults (4 men and 3 women; mean age = 32.9 ± 11.7 years) using a Teledyne FLIR A655sc infrared camera and ResearchIR version 4.40 software. Measurements were acquired at eight ocular surface locations (6 corneal and 2 scleral). Subjects performed 6 blinks at 5 interblink intervals (IBIs; at 2, 4, 6, 8, and 10 seconds), with 2-minute rests between sets. Two thermal metrics were evaluated: rate of temperature change (RTC) and magnitude of temperature change (ΔT). Effects of IBI and location were assessed using 1- and 2-way ANOVAs. Intraclass correlation coefficients (ICCs) quantified measurement reliability. Results: Both RTC and ΔT confirmed that OST decreased during each IBI. RTC was more sensitive than ΔT in detecting blink-induced thermal changes and declined significantly with increasing IBI (F = 12.88, P < 0.001). Variability also decreased at longer IBIs. RTC was not significantly affected by corneal location (F = 0.94, P = 0.45), although the inferior cornea showed the greatest variability (SD = 0.096). Scleral regions were significantly warmer than corneal sites (F = 48.67, P < 0.001). Averaging improved ICC from 0.879 (single) to 0.911 (3). Conclusions: RTC is a more sensitive and reliable OST metric. A 6-second IBI and averaging improve repeatability, supporting standardized thermal imaging protocols. Translational Relevance: These results support RTC-based OST as a repeatable tool for clinical diagnostics and tear film assessment.