A single-center study evaluating the effect of the controlled adverse environment (CAEsm) model on tear film stability

Abstract

PurposeTo investigate use of an improved ocular tear film analysis protocol (OPI 2.0) in the Controlled Adverse Environment (CAESM) model of dry eye disease, and to examine the utility of new metrics in the identification of subpopulations of dry eye patients.MethodsThirty-three dry eye subjects completed a single-center, single-visit, pilot CAE study. The primary endpoint was mean break-up area (MBA) as assessed by the OPI 2.0 system. Secondary endpoints included corneal fluorescein staining, tear film break-up time, and OPI 2.0 system measurements. Subjects were also asked to rate their ocular discomfort throughout the CAE. Dry eye endpoints were measured at baseline, immediately following a 90-minute CAE exposure, and again 30 minutes after exposure.ResultsThe post-CAE measurements of MBA showed a statistically significant decrease from the baseline measurements. The decrease was relatively specific to those patients with moderate to severe dry eye, as measured by baseline MBA. Secondary endpoints including palpebral fissure size, corneal staining, and redness, also showed significant changes when pre- and post-CAE measurements were compared. A correlation analysis identified specific associations between MBA, blink rate, and palpebral fissure size. Comparison of MBA responses allowed us to identify subpopulations of subjects who exhibited different compensatory mechanisms in response to CAE challenge. Of note, none of the measures of tear film break-up time showed statistically significant changes or correlations in pre-, versus post-CAE measures.ConclusionThis pilot study confirms that the tear film metric MBA can detect changes in the ocular surface induced by a CAE, and that these changes are correlated with other, established measures of dry eye disease. The observed decrease in MBA following CAE exposure demonstrates that compensatory mechanisms are initiated during the CAE exposure, and that this compensation may provide the means to identify and characterize clinically relevant subpopulations of dry eye patients.

External eye symptoms in indoor environments

“…For instance, one‐hour exposure of healthy subjects to 5% RH adversely affected PTF characteristics as similarly found in patients with DED; also, BF and fluorescein staining increased in patients with DED . Conversely, the exposure to controlled humidified air increases the PTF stability in DE patients by reduction in the mean break‐up area . Healthy students (n=39), that were exposed to different types of ventilation and draft in a climate chamber with controlled temperature and RH, reported significantly less DE symptoms by elevation of RH from 57% to 74%; however, the air velocity was substantially higher in the high RH condition, the finding should be considered cautiously.…”

TFOS DEWS II Tear Film Report

“…A number of approaches to improving repeatability have been suggested, including taking multiple readings and averaging or selecting a subset of values [82,83], minimizing the amount of fluorescein instilled [84–86] and, most significantly, eliminating the use of fluorescein altogether. This last approach, via a number of different methods, provides a non-invasive breakup time (NIBUT) value.…”

An evaluation of Retaine™ ophthalmic emulsion in the management of tear film stability and ocular surface staining in patients diagnosed with dry eye

“…Tear film stability and IBI, both assessments of drying on the ocular surface, were measured by the Ocular Protection Index (OPI) 2.0 System, an automated measure of ocular surface protection under normal blink pattern and normal visual conditions. 15 , 16 Video capture and analysis using the OPI 2.0 System allows for a calculation of mean corneal surface exposure, otherwise known as mean breakup area (MBA). Final endpoints were percent change in MBA and IBI in seconds.…”