The Eye

Question 1

Explain the drainage from the lacrimal gland

Answer 1

Lacrimal gland -> lacrimal sac -> lacrimal canal into eye, drains down nasolacrimal duct to inferior meatus of nasal cavity

Question 2

What are the boundaries of the orbit?

Answer 2

Apex= optic canal,
Sup= frontal and sphenoid,
Inf= zygomatic and maxilla,
Lat= zygomatic and sphenoid,
Med= lacrimal, ethmoid, maxillary and sphenoid

Question 3

Which part of the bony orbit is the weakest?

Answer 3

The inferior- zygomatic and maxilla

Question 4

What gives rise to the blind spot?

Answer 4

Where the optic nerve enters the retina (at the optic disc)

Question 5

What are the three layers surrounding the eye?

Answer 5

Inner retina,
Middle vascular- choroid,
Outer fibrous- sclera

Question 6

What do you do to look into the eye? Using what?

Answer 6

Fundoscopy using and ophthalmoscope

Question 7

Where is the optic disc always in relation to the nose?

Answer 7

Optic disc is always the nasal side of the fundus

Question 8

What happens in retinal detachment? What is the worry?

Answer 8

Retina pulls away from the choroid layer. Risk of retinal loosing blood supply and permanent partial blindness

Question 9

What are the 3 layers of mata around the optic nerve? Sup to deep

Answer 9

Dura, arachnoid, pia

Question 10

What type of humerous do the ant and post segments of the eye contain? What is the function of the posterior?

Answer 10

Ant- aqueous, post- vitreous, helps eye maintain its shape

Question 11

Describe the flow of aqueous fluid

Answer 11

Produced in ciliary body, flows through post chamber round lens and iris into ant chamber and out through trabecular mshowrk. All in ant segment

Question 12

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?

Answer 12

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

Question 13

What is a cataract? How do you treat it?

Answer 13

Lens becomes increasingly opaque giving blurry vision, under LA put new lens in, simple op

Question 14

What is the pneumonic for the muscles innervation?

Answer 14

LR6 SO4 R3

Question 15

What is the function of med, lat, sup, inf rectus muscles and inf and sup oblique?

Answer 15

Lat- outwards
Med- inwards
Sup rectus- up
Inf rectus- down
Sup oblique- down and in
Info oblique- up and out

Question 16

If there is a palsy in R sup oblique, what happens?

Answer 16

Cant look down and in ie when looking downstairs

Question 17

What 3 things might you see in an orbital blowout #? Why? How treat?

Answer 17

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

Question 18

What is the blood supply to the eye? What do it travel with?

Answer 18

Ophthalmic artery -> central retinal artery ->terminal branches (end arteries- only supply to retina). Travels with optic nerve

Question 19

What does central retinal artery occlusion look like? What happens to the pt?

Answer 19

Cherry red spot on a pale background. Immediate blindness, painless

Question 20

What is the venous drainage of the eye?

Answer 20

Central retinal vein -> sup opthalmic vein -> cavernous sinus

Question 21

What happens in central retinal vein occlusion? Name 2 causes

Answer 21

Drainage preventing causing oedema, can be caused by dehydration/thrombosis. Painless loss of vision

Question 22

What happens in conjunctivitis? Cause?

Answer 22

Conjunctiva inflamed (covers cornea and iris). Vessels dilate “red eye”, bacterial or viral

Question 23

What 3 things does the eyelid protect the eye from?

Answer 23

Excessive light, dryness, injury

Question 24

What is the difference between a Meibomian cyst and a Stye?

Answer 24

Cyst= tarsal gland inflamed, 
Stye= ciliary gland- treat with warm, salty washes

Question 25

Which two muscles open the eyelid? What is their innervation?

Answer 25

Levator palpebrae superioris (occulomotor),
Sup tarsal (sympathetic)

Question 26

What is the difference between partial and complete ptosis?

Answer 26

Partial- symp lesion, LPS works still.

Complete- OM nerve lesion

Question 27

Describe the direct and consensual pupillary light reflex? What are the afferent and efferent limbs? What are the two nuclei?

Answer 27

Direct= constriction from eye light shone into, consensual= response in other. 
Afferent= optic, to brainstem- pre-tectal nucleus -> EDW nucleus,
Efferent= OM

Question 28

What is accommodation? What is a loss of this called, what is the result?

Answer 28

Convergence of eyes with pupillary constriction. Presbyopia= loss of this therefore loss of focus

Question 29

Describe the corneal reflex?

Answer 29

Stimulate cornea and get reflexive contraction of palpebral part of obicularis occuli -> both eye shut.
Afferent= ophthalmic (trigeminal),
Efferent= facial

Question 30

What is pappiloedema? Symptoms?

Answer 30

Increase in ICP causes part of the optic nerve to swell. Can get vomiting, nausea, vision disturbances