Canonical Grading Scales of Corneal and Conjunctival Staining Based on Psychophysical and Physical Attributes.

Purpose: In this study, we apply psychophysical scaling principles based on physical (photometric) attributes of images to better understand the factors involved in clinician judgement of ocular surface staining and, using that knowledge, to develop photographic scales for the assessment of staining for dry eye (DE) and related conditions.

Methods: Subjects with noninfectious ocular surface staining were enrolled at five clinical sites. Following instillation of fluorescein, photographs of corneal staining were taken every 30 seconds for at least 5 minutes.

Isoflurane and ketamine:xylazine differentially affect intraocular pressure-associated scotopic threshold responses in Sprague-Dawley rats.

Purpose: Amplitudes of electroretinograms (ERG) are enhanced during acute, moderate elevation of intraocular pressure (IOP) in rats anaesthetised with isoflurane. As anaesthetics alone are known to affect ERG amplitudes, the present study compares the effects of inhalant isoflurane and injected ketamine:xylazine on the scotopic threshold response (STR) in rats with moderate IOP elevation.

Methods: Isoflurane-anaesthetised (n = 9) and ketamine:xylazine-anaesthetised (n = 6) rats underwent acute unilateral IOP elevation using a vascular loop anterior to the equator of the right eye.

Prevalence of visual impairment and uncorrected refractive error - report from a Canadian urban population-based study.

Purpose: The prevalence of visual impairment due to uncorrected refractive error has not been previously studied in Canada. A population-based study was conducted in Brantford, Ontario.

Methods: The target population included all people 40 years of age and older.

Human corneal adaptation to mechanical, cooling, and chemical stimuli.

Purpose: To psychophysically investigate adaptation in human corneas using the Belmonte pneumatic esthesiometer.

Methods: Twenty, 8, and 20 healthy subjects were enrolled in the mechanical, cool, and chemical experiments, respectively. Thresholds were estimated using an ascending method of limits and three intensities (subthreshold, threshold, and suprathreshold, in random order) were each presented 10 or 20 times, and subjects scaled the intensity of the stimuli (0-4 [no stimulus to very intense stimulus]).

Corneal, limbal, and conjunctival epithelial thickness from optical coherence tomography.

Purpose: To compare human central corneal, limbal and bulbar conjunctival epithelial thickness in vivo using an Optical Coherence Tomographer (OCT).

Methods: Thirteen healthy human subjects participated in this study. An OCT (Carl Zeiss, Meditec, Dublin, CA) was used to image central cornea, temporal corneo-scleral limbus and bulbar conjunctiva of the left eye.

Corneal, limbal, and conjunctival epithelium of bovine eyes imaged in vitro by using a confocal laser scanning microscope.

Purpose: To provide a description of the distribution and cell morphology, by using fluorescent markers and confocal laser scanning microscopy, of the corneal, limbal, and conjunctival epithelium of bovine eyes in vitro.

Methods: Fresh enucleated bovine eyes were dissected within 2 hours postmortem. Central cornea, limbus, and bulbar conjunctiva were imaged with confocal microscopy after staining with acridine orange (AO) or calcein-acetoxymethyl and ethidium homodimer-1.

Objective and subjective responses in patients refitted to daily-wear silicone hydrogel contact lenses.

Purpose: Silicone hydrogel (SiH) lenses offer many physiological advantages for daily wear (DW) in addition to the continuous-wear modality for which they were originally developed. The purpose of this study was to investigate the clinical performance and physiological responses in a group of successful long-term wearers of conventional hydrogel lenses when refitted with DW SiH contact lenses.

Methods: Eighty-seven successful soft lens wearers (8.

Comparison of human central cornea and limbus in vivo using optical coherence tomography.

Purpose: The purpose of this study was to compare central corneal and limbal total and epithelial thickness using a commercially available optical coherence tomographer.

Methods: A Humphrey-Zeiss Optical Coherence Tomographer (OCT [Carl Zeiss, Meditec, Dublin, CA]) was used to obtain corneal images from 10 subjects. Central corneal and limbal total and epithelial thickness of both eyes were measured using the OCT.

The inhibitory interaction between human corneal and conjunctival sensory channels.

Purpose: To explore human corneal and conjunctival sensory channels at suprathreshold level.

Methods: Ten healthy human subjects participated in the study. The Belmonte pneumatic esthesiometer was used to apply mechanical and chemical stimuli to the central cornea and temporal conjunctiva of the left eye.

Characteristics of human corneal psychophysical channels.

Purpose: To characterize human corneal psychophysical channels.

Methods: Twenty subjects participated in this study. A Belmonte pneumatic esthesiometer was used to deliver stimuli, and the ascending method of limits and the method of constant stimuli were used to estimate thresholds.

Nociceptive sensation and sensitivity evoked from human cornea and conjunctiva stimulated by CO2.

Purpose: To compare sensation and sensitivity evoked from human cornea and conjunctiva stimulated by CO2.

Methods: Twenty healthy participants were recruited for the study. Central corneal and temporal conjunctival chemical sensation and sensitivity of only one eye of each subject were evaluated.