The Eye Flashcards
Explain the drainage from the lacrimal gland
Lacrimal gland -> lacrimal sac -> lacrimal canal into eye, drains down nasolacrimal duct to inferior meatus of nasal cavity
What are the boundaries of the orbit?
Apex= optic canal, Sup= frontal and sphenoid, Inf= zygomatic and maxilla, Lat= zygomatic and sphenoid, Med= lacrimal, ethmoid, maxillary and sphenoid
Which part of the bony orbit is the weakest?
The inferior- zygomatic and maxilla
What gives rise to the blind spot?
Where the optic nerve enters the retina (at the optic disc)
What are the three layers surrounding the eye?
Inner retina,
Middle vascular- choroid,
Outer fibrous- sclera
What do you do to look into the eye? Using what?
Fundoscopy using and ophthalmoscope
Where is the optic disc always in relation to the nose?
Optic disc is always the nasal side of the fundus
What happens in retinal detachment? What is the worry?
Retina pulls away from the choroid layer. Risk of retinal loosing blood supply and permanent partial blindness
What are the 3 layers of mata around the optic nerve? Sup to deep
Dura, arachnoid, pia
What type of humerous do the ant and post segments of the eye contain? What is the function of the posterior?
Ant- aqueous, post- vitreous, helps eye maintain its shape
Describe the flow of aqueous fluid
Produced in ciliary body, flows through post chamber round lens and iris into ant chamber and out through trabecular mshowrk. All in ant segment
What can occur if the drainage of fluid from the ant chamber of the eye is blocked? What is it called? Is it an emergency? How do you treat it?
Open angle glaucoma- fluid cant drain, ant chamber distended pushing back on vitreous humour which can compress optic nerve distorting vision. Not a medical emergency, give eyedrops to unblock meshwork
What is a cataract? How do you treat it?
Lens becomes increasingly opaque giving blurry vision, under LA put new lens in, simple op
What is the pneumonic for the muscles innervation?
LR6 SO4 R3
What is the function of med, lat, sup, inf rectus muscles and inf and sup oblique?
Lat- outwards Med- inwards Sup rectus- up Inf rectus- down Sup oblique- down and in Info oblique- up and out
If there is a palsy in R sup oblique, what happens?
Cant look down and in ie when looking downstairs
What 3 things might you see in an orbital blowout #? Why? How treat?
Tear drop sign MRI- increase in pressure in the eye pushes the eye down through the inf boarder (weakest).
Cant look up- inf rectus tethered eye down as pulled into teardrop.
Bruising- sup veins damaged.
Many resolve some need surgery
What is the blood supply to the eye? What do it travel with?
Ophthalmic artery -> central retinal artery ->terminal branches (end arteries- only supply to retina). Travels with optic nerve
What does central retinal artery occlusion look like? What happens to the pt?
Cherry red spot on a pale background. Immediate blindness, painless
What is the venous drainage of the eye?
Central retinal vein -> sup opthalmic vein -> cavernous sinus
What happens in central retinal vein occlusion? Name 2 causes
Drainage preventing causing oedema, can be caused by dehydration/thrombosis. Painless loss of vision
What happens in conjunctivitis? Cause?
Conjunctiva inflamed (covers cornea and iris). Vessels dilate “red eye”, bacterial or viral
What 3 things does the eyelid protect the eye from?
Excessive light, dryness, injury
What is the difference between a Meibomian cyst and a Stye?
Cyst= tarsal gland inflamed, Stye= ciliary gland- treat with warm, salty washes
Which two muscles open the eyelid? What is their innervation?
Levator palpebrae superioris (occulomotor), Sup tarsal (sympathetic)
What is the difference between partial and complete ptosis?
Partial- symp lesion, LPS works still.
Complete- OM nerve lesion
Describe the direct and consensual pupillary light reflex? What are the afferent and efferent limbs? What are the two nuclei?
Direct= constriction from eye light shone into, consensual= response in other. Afferent= optic, to brainstem- pre-tectal nucleus -> EDW nucleus, Efferent= OM
What is accommodation? What is a loss of this called, what is the result?
Convergence of eyes with pupillary constriction. Presbyopia= loss of this therefore loss of focus
Describe the corneal reflex?
Stimulate cornea and get reflexive contraction of palpebral part of obicularis occuli -> both eye shut.
Afferent= ophthalmic (trigeminal),
Efferent= facial
What is pappiloedema? Symptoms?
Increase in ICP causes part of the optic nerve to swell. Can get vomiting, nausea, vision disturbances
