2.  Pupil  Opening in iris  Color determined by:  Number of melanocytes  No melanocytes = blue eyes  Increasing number of melanocytes = green, brown and black eyes  Albinos = Pale gray or gray blue eyes

4.  Susensory Ligaments  Hold lens in place

6.  AKA: Retina  Innermost layer  Photoreceptors—cells that detect light  Rods—light sensitive  “low light vision”  Cones—color  Sharper images  Requires light

9.  Macula lutea  Where most cones are  In center—fovea centralis

11.  Optic Disc  Origin of optic nerve  Contains blood vessels  No photoreceptors  “Blind spot”  Brain fills in missing information

13.  Anterior chamber—cornea to iris  Posterior chamber—iris to lens  Aqueous humor—fills both chambers  Maintains shape of eye  Transports wastes and nutrients  Vitreous body—in posterior chamber  Maintains shape of eye

15.  Interference with circulation  Increase in pressure  Leads to blindness if untreated

16.  Focus image on photoreceptors  Transparent  Contract and changes shape

18.  Lens loses transparency  Due to drugs, injury or radiation  Most common: senile cataracts  Becomes cloudy with age  Visual clarity fades  Need bright lights to see  Treatment:  Remove old lens  Replace with artificial lens  Fine tune with glasses or contacts  No treatment = blindness