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Advisory Committee Chair

Roderick Fullard

Advisory Committee Members

Dennis Pillion

Tammy Than

Document Type

Thesis

Date of Award

2013

Degree Name by School

Master of Science (MS) School of Optometry

Abstract

Purpose: For patients suffering from aqueous-deficient dry eye, non-stimulated (NS) tear collection can be challenging and time-consuming. Adding a small volume of sterile saline to the eye allows a "washout" (WO) tear collection that takes considerably less time. The primary goal of this project was to determine if WO tear collection is a viable alternative to NS tears for comparing the levels of common ocular surface biomarkers in patients with and without aqueous-deficient dry eye (AD). Stimulated (Stim) tears were also investigated as a second possible alternative to NS tears. Methods: Two studies were conducted, tear cytokine levels being measured using a 27-Plex BioRad cytokine assay. In the first study, NS and WO tear samples were collected from 23 non-AD patients and 26 AD patients, group allocation being determined by Schirmer score (wetting length). WO tears were collected after instillation of 10µL sterile saline to the lower conjunctival fornix. T-tests, correlation analyses and Bland-Altman plots and analyses were performed to determine the agreement between cytokine levels in NS and WO samples. In the second study, matching NS, WO, and Stim samples were collected from 15 patients. ANOVA and post-hoc comparisons of means were performed for comparison of NS, WO, and Stim tear samples. Results: In Study 1, 11 of 25 routinely detected cytokines showed a significant difference between NS tears of non-AD and AD patients. Five of the 11 also showed a significant difference between WO tears of non-AD and AD patients. In Study 2, greater differences between NS and Stim tears than between NS and WO tears were clearly evident and Stim tears showed little potential to replace NS tears. Discussion: The WO tear collection method appears to be a viable substitute for NS tear collection for many inflammatory biomarkers and in distinguishing major differences between non-AD and AD patients. Some subtle differences between non-AD and AD samples are lost in the WO method. Stim tear collection is not a reliable or practical alternative to NS tear collection and shows little potential to differentiate non-AD from AD dry eye patients.

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Optometry Commons

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