Andrew L. Nguyen

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PURPOSE Dry eye disease is a common condition that affects millions of people world wide. The common findings of dry eye disease are blurred vision and tear film instability. The purpose of this study was to determine if long-term use of artificial tears altered visual disturbances and tear film instability of dry eye patients. METHODS Contrast(More)
PURPOSE The purpose of this investigation was to measure the precorneal residence time of saline and five marketed artificial tears in dry eye subjects using fluorometry. METHODS FITC-dextran, 70 kDa molecular weight, was admixed under sterile conditions (0.1% wt/vol) into buffered saline and the marketed artificial tear formulations of varying viscosity.(More)
PURPOSE It was the purpose of this investigation to examine both retention time (RT) and retention of effect of two ophthalmic formulations in the same dry eye subjects. METHODS This was a randomized, subject-masked cross-over study. Dry eye subjects, characterized by sub-type, were recruited. For direct RT measurement, fluorescein isothiocyanate(More)
PURPOSE The purpose of this work was to gather preliminary data in normals and dry eye subjects, using a new, non-invasive imaging platform to measure the thickness of pre-corneal tear film. METHODS Human subjects were screened for dry eye and classified as dry or normal. Tear film thickness over the inferior paracentral cornea was measured using laser(More)
PURPOSE The study purpose was to evaluate corneal barrier function and staining relative to potential bioincompatibilities. METHODS This was a randomized double-masked study (n = 25 subjects). Three lens material-care solution combinations were tested: (1) lotrafilcon B/polyhexamethylene biguanide (PHMB)-based multipurpose (MPS) solution (MPS-1); (2)(More)
PURPOSE It is well established that visual acuity (VA) decreases with luminance but the specific factors that are responsible remain unclear. The purpose of this study was to quantify the contributions of accommodative error, pupil size, and higher-order aberrations to the decrease in VA when transitioning from photopic to mesopic light levels.(More)
PURPOSE This pilot study compared traditional methodologies; manifest refraction and keratometry, with that of newer technologies; corneal topography, and optical pachymetry, in assessing corneal and refractive stabilization after soft contact lens wear in photorefractive candidates. The timeline differences among these various technologies in determining(More)