Physiology Of Optics Flashcards
Describe cornea
Transparent
Non vascularized
Provide protective coating
Effect of the obstruction of aqueous humor
Increase intraocular pressure
Glaucoma - leads to damage of retina and optic nerve, cause blindness
3 functions of aqueous humor
Maintain eye pressure
Maintain cornea shape
Nourish lens and cornea
Immunological function
Function of lens
Focuses light ON the RETINA
Pupil and muscle of iris in bright light
Circular muscle of iris contract
Pupil constrict
Pupil and muscle of iris in dim light
Circular muscle of iris relax
Radial muscle of iris contract
Pupil dilates
Dilation of pupil
Sympathetic stimulation : mydriasis
Pupil constriction
Parasympathetic stimulation : miosis
Functions of vitreous humor
Mainatain posterior pressure to lens
Clear debris by phagocyte
Help clean the retina
Describe emmetropia
Normal eye : light rays from object are parallel and focus on the retina without effort
Describe the lens in distance vision (3m)
Ciliary muscle relax
Zonular ligament contract / stretch
Lens is thin
Describe lens in near vision (3m)
Ciliary muscles contract
Zonular ligaments relax
Lens is thicker
Describe visual axis
Midpoint of visual field to fovea
Describe optic axis
Longest A-P diameter of the eye, middle of cornea to posterior pole
Describe presbyopia and how it is corrected
Loss of accomodation of lens because decrease in elasticity as aging
Corrected by convex lens