The Effects of Contact Lenses With Experimental Dye on Visual Function

The two-point light spread function was assessed at visit 2 for each subject eye under two conditions with a distance filter and without a distance filter. Measurements for this metric were taken twice, with the presence of an additional UV/HEV light source and without this additional light source (the same study lenses were used for both measurements). Two-point light spread function is defined that the as the minimum distance (mm) that two points of light are completely distinct. Measurements for this metric are positive. Smaller distances indicate better lens performance. The average distance for each lens type and light source combination was reported across age groups.

The appearance of Halos was assessed at visit 2 for each subject eye. Measurements for this metric were taken twice, with the presence of an additional UV/HEV light source and without this additional light source (the same study lenses were used for both measurements). Halos were quantified as the diameter (mm) of the outer edges of the Halo. Measurements for this metric are positive. Smaller diameter indicates better lens performance. The average diameter (mm) for each lens type and light source combination was reported across age groups.

The appearance of starbursts was assessed at visit 2 for each subject eye. Measurements for this metric were taken twice, with the presence of an additional UV/HEV light source and without this additional light source (the same study lenses were used for both measurements). Starbursts are defined as the diameter (mm) of the light's lateral spread. Measurements for this metric are positive. Smaller diameter indicates better lens performance. The average diameter (mm) for each lens type and light source combination was reported across age groups.

The Glare disability threshold was assessed for each eye at visit 1. The study lenses in this visit were assessed without the additional light sourced used at visit 2. Subjects were exposed to a target stimulus for 2 seconds; before the measurement was taken the annulus was set to a level below that which would cause the target stimulus to be veiled. The experimenter would then adjust the intensity of the annulus until subjects could no longer see the target stimulus. Subjects would indicate this by pressing a buzzer. Glare disability thresholds take on positive values, where higher values indicate better lens performance. The average glare disability level (change in log relative energy) for each lens type was reported across age groups.

Photostress Recovery (PR) Time (seconds) was assessed for each eye at visit 1. The study lenses in this visit were assessed without the additional light sourced used at visit 2. Subjects are exposed to a target, once the target was able to be comfortable viewed by the subject, a bright bleaching light covered it. As the afterimage fades, participants will gradually be able to re-gain sight of the target. PR time will be recorded as the time it takes following exposure to the bleaching light to regain sight of the target. PR Times are positive values where smaller times indicate better lens performance. The average PR Time (seconds) for each lens type was reported across age groups.

The Glare discomfort (change in palpebral fissure height) was assessed for each eye at visit 1. The study lenses in this visit were assessed without the additional light sourced used at visit 2. Glare discomfort can take on negative and positive values, where smaller values indicate better lens performance. The average glare discomfort (change in palpebral fissure height) for each lens type was reported across age groups.

Heterochromatic Contrast Threshold was assessed for each eye at visit 1. The study lenses in this visit were assessed without the additional light sourced used at visit 2. Heterochromatic contrast thresholds are measured as thresholds to a variable wavelength central target presented on a short-wave (460nm) sky-light background. Thresholds are positive values, where higher values indicate better lens performance. The average threshold each lens type was reported across age groups.