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Christian Sundstrom, Keith Jeffrey Lane, Endri Angjeli, Peter Corcoran, George W Ousler; Ocular Surface Thermal Imaging Pre- and Post-CAESM. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2851.
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© ARVO (1962-2015); The Authors (2016-present)
To examine inter-blink ocular surface temperature change before and during exposure to a Controlled Adverse Environment (CAESM), using a FLIR A655sc thermal camera, in association with fluorescein staining assessments pre- and post-exposure.
5 normal subjects participated who had no history of ocular surface disease, no prior diagnosis of dry eye, no current symptoms of ocular discomfort, and no history of artificial tear use. Thermal videos were acquired before CAESM exposure, and at the final 5 minutes of the 45-minute exposure. Fluorescein staining was conducted at least 1 hour prior to CAE exposure, to allow dye sufficient time to wash out. Staining was subsequently conducted immediately after exit from the CAESM.
Mean cooling rate (oC/sec over blink interval) pre-CAE was 0.04 oC/sec, and mean percent drop in temperature (over each blink interval) was 0.36%. Within-CAE cooling rate was 0.13 oC/sec, and mean percent drop was 0.79%. Although these findings trend in the positive direction, neither mean cooling rate nor mean percent drop in temperature increased significantly (p = 0.12, 0.16, respectively). Mean corneal fluorescein staining increase pre- to post-CAESM was 2.5 units on the Ora Calibra 1.0 Staining Scale. The correlation between fluorescein staining increase and rate of cooling within-CAE was 0.82.
The effect of a challenge environment on thermal properties of the tear film was established. The high correlation between tear film cooling rates and formation of SPK within the CAE was also documented (R=0.82). These findings suggest that an enhanced rate of tear film cooling may indicate an enhanced rate of tear film evaporation, leaving the cornea exposed to environmental airflow and resulting in formation of corneal SPK. These findings also suggest that thermal properties of the tear film may be modifiable with a challenge environment.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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