glare


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glare

(glār),
A sensation caused by brightness within the visual field that is sufficiently greater than the luminance to which the eyes are adapted; results in annoyance, discomfort, and decreased visual performance.

glare

(glār) discomfort in the eye and depression of central vision produced when a bright light enters the field of vision, particularly when the eye is adapted to dark. It is direct g. when the image of the light falls on the fovea and indirect g. when it falls outside the fovea.

glare

a strong, dazzling light that may cause discomfort to the eye. Visual problems that result from glare often involve inadequate lighting conditions; they particularly affect individuals with cataracts or other disease conditions. The condition is relieved somewhat by using incandescent rather than fluorescent lighting, wearing a visor, wearing special antiglare lenses, and using a matte-black cardboard typoscope for reading words on a glaring white paper.

glare

A visual condition in which the observer feels either discomfort and/or exhibits a lower performance in visual tests (e.g. visual acuity or contrast sensitivity). This is produced by a relatively bright source of light (called the glare source) within the visual field. A given bright light may or may not produce glare depending upon the location and intensity of the light source, the background luminance, the state of adaptation of the eye or the clarity of the media of the eye.
direct glare Glare produced by a source of light situated in the same or nearly the same direction as the object of fixation.
disability glare Glare which reduces visual performance without necessarily causing discomfort.
discomfort glare Glare which produces discomfort without necessarily interfering with visual performance.
eccentric glare See indirect glare.
indirect glare Glare produced by an intense light source situated in a direction other than that of the object of fixation. Syn. eccentric glare.
glare source See glare.
glare tester An instrument for measuring the effect of glare on visual performance. There exist several (e.g. Brightness Acuity Tester (BAT), Miller-Nadler Glare Tester, Optec 1500 Glare Tester). Glare testing is valuable in patients with corneal and lenticular opacities before and after surgery and in elderly patients in whom adaptation to glare is usually more difficult. The Miller-Nadler Glare Tester consists of a glare source surrounding a Landolt C. The instrument contains 19 black Landolt C, all of the same size, 6/120 (or 20/400). Each Landolt C is presented in one of four orientations and from the highest to the lowest contrast at which the subject can no longer judge in which direction the letter appears. The contrast threshold is expressed in percentage disability glare.The
Brightness Acuity Tester (BAT) is a standardized glare source of light. It is presented in a hemisphere held over one eye. The light source can subtend a visual angle of 8 to 70 degrees at a vertex distance of 12 mm. The patient is asked to read a visual acuity chart through a small aperture in the hemisphere. The chart can be a low-contrast or high-contrast log MAR visual acuity chart or, for example, the Pelli-Robson contrast sensitivity chart.
veiling glare Glare caused by scattered light and producing a loss of contrast.
References in periodicals archive ?
Translucent glass partitions and antiglare finishes also help bounce light through the space without creating glare or hot spots, Jayson adds.
Unlike nighttime sources of disability glare, we can mitigate the effects of daytime glare in offices and schools by using body language to shift our gaze, and shades to block glare from the windows.
Several glare indicators targeted to issues caused by artificial luminaries including CGI (Einhorn 1969), VCP (CIE 1995), and UGR (CIE 1995) while others targeted to issues caused by daylight such as DGI (Osterhaus 2005), and DGP (Wienold and Christoffersen 2006).
Sims contracted Miami, Florida-based product management services leader Innovation Direct[TM] to represent the Phone Glare to potential licensees for a 2 year period.
Yet, when luminaire efficacy governs equipment selection, or when power density drives lighting design, glare control may be overlooked.
The square moves with the wearer to block the source of glare at any angle, but still allows the surroundings to remain visible.
ICAT has taken the initiative to work on this problem and to host this unique demonstration in our country that has highlighted the aspects of anti glare phenomena for head lighting system.
He concludes: "Finally, make it a habit to lower sun visors to help block some of the reflected light and attempt, when possible, to take an alternate route lined with tress or tall buildings instead of one with extreme glare.
It's like a glare comes off the backboard and that big glass window.
Veiling glare significantly reduces contrast and resolution, creating a visible haze that reduces clarity.
The glare shield keeps sunlight off the cockpit instrument panel and it's not very sturdy.
The porosity of the glass-and-air coating brings with it a bonus: It prevents glare.