Mydriasis Mydriasis Mydriasis () is the dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, trauma, or the use of drugs. Normally, as part of the pupillary light reflex, the pupil dilates in the dark and constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day. A "mydriatic" pupil will remain excessively large even in a bright environment. The excitation of the radial fibres of the iris which increases the pupillary aperture is referred to as a mydriasis.
What a Pleasure Stakes What a Pleasure Stakes The What a Pleasure Stakes is an American flat Thoroughbred horse race for two-year-olds held annually at Calder Race Course in Miami Gardens, Florida. It is currently an ungraded stakes race run over a distance of 8.5 furlongs on dirt. The race has traditionally been held during the Tropical at Calder meet, from late October through early January. This meet normally has some of the strongest stakes programs of Calder’s eight-month season. Due to permit disputes with Hialeah Park Race Track, the race was pushed back in 1987 and 1991 into the following year. Both of