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Fiona Soong, Holly Irene Lorentz, Stephanie Recker, Chuck Shi, James J Mun, Anne Marie Salapatek; Ocular Signs and Symptoms in non-symptomatic CL wearers under controlled humidity settings in an Environmental Exposure Chamber (EEC). Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):6114.
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© ARVO (1962-2015); The Authors (2016-present)
An investigational study to evaluate ocular signs and symptoms of non-symptomatic CL wearers in low and moderate humidity conditions using the Environmental Exposure Chamber (EEC) model.
10 non-symptomatic adapted CL wearers were screened and randomized to a treatment sequence of two different CL materials (etafilcon A [ETA] and senofilcon A [SEN]) worn at four EEC visits in which the environmental conditions were set to either 10±3% RH or 50±5% RH, an air flow of 2-5ft/sec and a temperature of 23±3°C. On each EEC visit, objective measures such as TBUT, corneal and conjunctival staining, conjunctival redness, blink rate and LWE were taken prior to EEC entry and CL insertion as well as post EEC exit and CL removal. Subjective symptoms including grittiness, tearing, burning, itching, dryness, soreness, sensitivity to light, blurring, and discharge were rated 0-4 using electronic Patient Data Acquisition Tablets (ePDAT™) at set intervals during the visit.
All objective and subjective measures deteriorated with exposure time in both controlled humidity EEC settings when lenses were worn on eye for 150min. Conjunctival redness LSMeans, was statistically higher (p<0.05) in the RH 10% condition (max 3.44±1.49) than the RH50% condition (max 2.35±1.25). Blink rate per minute increased for the first 40 minutes before reaching a plateau and the LSMeans was statistically higher (p<0.05) in RH10% (max 43.85±17.95) than RH50% conditions (max 35.20±12.17).
The EEC model can control humidity, air flow and temperature to elicit dry eye conditions in a short period of time in CL wearers who are habitually non-symptomatic. In this small investigational study that determined differences in CL dehydration, conjunctival redness and blink rate were the two measurements that showed differentiation between the two RH conditions.
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