10 - Head & Neck - The Eye 2 Flashcards
How does closed-angle glaucoma present?
Sudden onset of:
- Painful red eye
- Blurred vision/halos around objects
- Fixed or semi-dilated, irregular, oval-shaped pupil
- Nausea + vomiting
- Eye is hard + tender on palpation
What is the treatment for closed-angle glaucoma?
- Muscarinic agonist eye drops ie Pilocarpine
- Emergency ophthalmology referral
Name the 2 muscles which form the iris:
1) Sphincter pupillae
2) Dilator pupillae
Nerves from which ganglia innervate the muscles with the iris?
Parasympathetic = Ciliary ganglion > Sphincter pupillae muscle Sympathetic = Superior cervical ganglion > Dilator pupillae muscle
The thickness of the lens is controlled by which nerve?
Parasympathetic fibres of CN III
What 3 factors make up the accomodation reflex? How do we test for this reflex clinically?
1) Convergence
2) Rounding of the lens
3) Pupil constriction
Direct + consensual pupillary light reflexes
If the ciliary muscle contracts, what happens to the shape of the lens? What type of vision does this allow?
It becomes more biconvex = rounder to allow near vision
- Contraction of the ciliary muscle causes relaxation of suspensory ligaments
Name the bands of dense connective tissue which give the eyelids their shape:
Tarsal plates
Where are the Meibomian glands located, and what type of secretions do they produce?
Tarsal plates of the eyelids,
Oily secretions to prevent evaporation of tears
Name the parts of the lacrimal apparatus:
- Lacrimal glands
- Lacrimal ducts
- Lacrimal canaliculi
Where does the nasolacrimal duct drain into?
Inferior meatus of nasal cavity
Which muscle is responsible for closing the eye, and what nerve innervates it?
Orbicularis oculi
CN VII
Which muscle is responsible for opening the eye, and which nerve innervates it?
Levator palpebrae superioris
CN III
Why does meningitis cause photophobia?
The optic nerve is wrapped in the 3 layers of the meninges, therefore if there is increased intracranial pressure, this will compress the optic nerve.
Name the artery which supplies the muscles and tissues in the eye:
Which branch of this artery supplies the retina?
Ophthalmic artery
Central artery to retina
The Ophthalmic artery is a branch of which artery?
Internal Carotid artery
Describe the venous drainage of the muscles and tissues in the eye:
- Ophthalmic veins
- -> Cavernous sinus
- –> Internal jugular vein
How would a central retinal artery occlusion appear during a fundoscopy? What are the risk factors for this?
Cherry red spot on a light background
- Atherosclerosis
- High cholesterol
- Increasing age
- Dehydration
Name the 6 muscles which control the movements of the eye:
- Superior rectus
- Superior oblique
- Inferior rectus
- Inferior oblique
- Lateral rectus
- Medial rectus
Which nerve innervates most of the ocular muscles? What are the exceptions?
CN III except…
- Lateral Rectus = CN VI
- Superior oblique = CN IV
*LR6SO4
Which muscle causes the eye to look downwards when it is in the medial position?
Superior oblique
Which muscles allow us to look to our right?
Right eye = lateral rectus
Left eye = medial rectus
Which muscles allow us to look up and right?
Right = superior rectus Left = inferior oblique
Which muscles allow us to look down and right?
Right = Inferior rectus Left = Superior oblique
Which muscles allow us to look straight up?
Both eyes: Inferior oblique + superior rectus
If the inferior oblique is damaged, which eye movement cannot occur?
Look up and medial
Why is it not possible to lose a contacts lens behind the eye?
If a contact lens become displaced from the cornea, it could not extend beyond the point of the conjunctival reflection, where if leaves the sclera and lines the eyelids
During fundoscopy, which structure will always be on the nasal side, allowing you to orientate a picture?
Optic disc always on nasal side
- whiter structure from where the arteries arise
= BLIND SPOT
Name the area of the retina which contains the photoreceptors for acuity of vision:
Macula lutea
fovea centralis is the central depression, the region for most acute vision
What is papilloedema?
Swelling of the optic disc due to raised intracranial pressure
