The Eyeball, Ocular Muscles and Neurovasculature Flashcards
How is the aqueous chamber split up? How is it made?
Anterior and Posterior chambers
Ciliary body secrete aqueous humour which fills both chambers
What is the iris?
Thin contractile diaphragm with central aperture for transmitting light.
2 muscles to control size of pupil
How does the lens work?
Biconvex structure attached to the ciliary body by suspensory ligaments that changes shape as the ciliary body contracts
What layers make up the retina?
Neural layer - light sensitive
Pigmented layer - contain melanocytes to absorb some light
What is the optic disk?
Depressed part of eye where nerve fibres join optic nerve.
No photoreceptors
What is the macula?
Area lateral to optic disk where photoreceptors are specialised for acuity - high density of cone cells
The centre part of the macula is known as the fovea and has the most acute vision
What vasculature supplies the retina?
Central Retinal Artery/Vein
What is exophthalmos? When is it seen?
Eyeballs protrude and eyelids part more than usual - whites of eyes visible all round cornea and iris
Diseases like thyroid disease
What can particulates in the eye cause?
Corneal abrasions
This causes sudden pain and excess tears
What can injury to the trigeminal nerve leave you susceptible to?
Foreign particles on the cornea
How does the lens change with age?
Flattens and hardens
Reduced focusing capacity - presbyopia
Partial/complete opacity of the lens - cataracts
What can blunt trauma to the eye cause?
Hyphema - bleeding into anterior chamber
How can a raise in CSF pressure cause occular problems?
Optic nerve surrounded by meninges with CSF in subarachnoid space
Compress optic nerve, central retinal vein and then artery
What are the muscles of the orbit?
Levator Palpabrae Superioris
4 Recti - superior, inferior, medial, lateral
Superior Oblique
Inferior Oblique
What nerves innervate the muscles of the orbit?
LR6 SO4 R3
Lateral rectus - 6 - abducens
Superior oblique - 4 - trochlear
Rest - 3 - oculomotor
