Optimizing Measurement Parameters for Ocular Surface Temperature Assessment Using ResearchIR Software

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.

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.

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).

RTC is a more sensitive and reliable OST metric. A 6-second IBI and averaging improve repeatability, supporting standardized thermal imaging protocols.

These results support RTC-based OST as a repeatable tool for clinical diagnostics and tear film assessment.