<unk>  is the dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of<unk>  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<unk> . More generally,<unk>  also refers to the natural dilation of pupils, for instance in low light conditions or under sympathetic stimulation. Fixed, unilateral<unk>  could be a symptom of raised intracranial pressure. The opposite, constriction of the pupil, is referred to as miosis. Both<unk>  and miosis can be physiological. Anisocoria is the condition of one pupil being more dilated than the other.
Mydriasis
Periocular injection
Conjunctival suffusion
Ocular tremor
Iontophoresis
Subconjunctival injection
Nephroptosis
Pityriasis