IRIS Flashcards
What does the uvea consist of:
iris, choroid and ciliary body
what is an iris tremor?
Iridodonesis - occurs when lens is missing or displaced = iris is unsupported
Iris function
Varies amount of light reaching retina
Reduces abberations
communicates emotion
provides route for metabolites to and from aqueous
what is direct reflex
when light is shone= pupil contracts
Location of iris
anterior - bathed in aqueous
Peripherally - continuous with ciliary body at iris root
Posterior - iris rests on crystalline lens
What is near reflex
miosis occurs when eye accommodates or converge, reduces spherical aberration and increases depth of field
pain reflex?
Pain - pupil dilation
Fear - pupil dilation and eyelids retract
corneal/ conjunctival/eyelid reaction
pupil constricts
consensual reflex?
increase in luminance in one eye gives a direct reflex = a delayed constriction of pupil in other eye
Diameter of iris
13mm
Iris colour is inherited, which is dominant and recessive
brown = dominant
recessive =blue
what is mydriasis
Dilation - pupil gets bigger
What is miosis
Constriction - pupil gets smaller
when does the width of ciliary region change
changes most during miosis and mydriasis, the width of pupillary zone remains constant
3layers of iris structure
anterior border layer, storm and epithelium
