Part 3 Flashcards
Extraocular muscles of eye
7 total
- 4 recti- sup inf medial and lateral
- 2 obliques- superior and inf
- 1 Lavator palpebra superioris
- Originate from annulus of Zinn. **Except **for inferior oblique that originates form the lacrimal bone
-Inserted behind equator of eye ball.
-sup. Oblique takes turn at the trochlea
-thinnest and longest muscle- sup oblique - innervation by CN3 for all muscles EXCEPT SO4 and LR6
Intraoccular muscles of eye
3 total
- sphincter pupilae _ innervated by 3CN
- dilator pupilae _ innervated by sympathetic nerves
- cilliary muscles.
Esotropia
- median deviation/ adduction of eye
- Type of strabismus/ squint
Exotropia
-lateral deviation/ abduction of eye
Myopia
Far vision
Hypermetropia
Near vision
Agre related refractive error called?
Presbyopia
Test to asses squint
Hirschberg test
Light reflex
1 mm deviation - 15 diopters
2 mm deviation - 30 diopters
3 CN palsy
- ptosis
- down and out eye
LPS - ptosis
SR + IO - for downward eye
medial rectus - for outward eye
Muscles responsible for elevation of eye
SR and INF. OBLIQUE
Function of external muscles
SIN- all superiors are introters
All inferiors are extroters
RAD- all recti are adductors
All obliques are abductors
SO- ABID- sup. Oblique=
Abduction - intorsion - depression
6CN palsy
- lateral rectus muscle
- primary gaze normal
- eye will not move laterally in affected side
- Diplopia
- head turn toward same side
4CN palsy
- diplopia on down gaze
- head turn towards opposite side
- sup. Oplique
- eye will be down only.
Ambyopia RX
- Lazy eye
- Occlusion/ patching of the normal eye
- anblyogenic period- 7-8 years
- can be treated till 14 years
Papilledema
- Reactionary disc edema
- 8 times enlarged size
- Angry sun appearance
- Venous tortuousity
- Increased intracranial pressure
- increased size of blind spot in perimetry
- pupil and vision is normal
Most common cause of optic neuritis?
Multiple Sclerosis
Optic neuritis
1- papillitis
involvement of optic Disc
- size 2x enlarged OD
-RAPD (Marcus Gunn pupil)
2- neuroretinitis
** involvement of optic nerve + OD + macula**
- cystoid macular edema causing macular star appearance
Primary optic atrophy
Death of ganglionic cells
- Primary- trauma toxins tumours
- Chalky white appearance of OD
- Secondary- after papillitis or neuroretinitis
- grey white OD
1st order neurons of visual pathway?
Rods and cones
Visual pathway
- optic nerve
Cross innervation (nasal side responsible for temporal vision and vv) - optic chiasma
Only nasal fibres cross at optic chiasma - optic tract
- terminate in lateral geniculate body
- optic radiation
- visual cortex (occipital lobe)
Anopsia
- complete loss of vision of whole eye
- damage of optic nerve
- will affect same side
Bitemporal hemianopia
- damage of optic chiasma nasal fibres
- compression of chiasma by tumours prolactinoma and craniopharyngioma
- will affect opposite side
- nasal fibres damage will cause temporal side vision loss
Homonymous hemianopia
- same side vision loss
Either right sided or left sided - always CONTRA LATERAL
- damage to optic tract
- same side ka vision loss, opposite side ka lesion
All lesions below the optic chiasma will cause?
Homonymous hemianopia
All lesions below optic chiasma will affect which side
Contra lateral side
Color blindness
X linked recessive
(Only affect males, females will be carriers)
- Most common- Deuteranopia green color
- PuRe- protanopia for red
- TB - tritanopia for blue color
ishihara chart to check red and green
Uvea composed of?
Iris
Cilliary body
Choroid
Uveitis types
1- anterior
2- intermediate
3- posterior uveitis
Anterior- iritis, iridocyclitis
Intermediate- pars planitis
Posterior- choroiditis
All parts- pan uveitis
Uveitis (ant)
- cells (inflammatory) seen in ant. chamber-
- if cells attach behind cornea - keratin precipitates KPs
- mutton fat KPs in granulomatous
- thin fine KPs in non granulomatous
- KPs arranged in triangle pattern- Arlt’s triangle ant uve
- irregular pupil due to adhesions
- 360• adhesions = iris bombe
- Irregular dilated pupil - festooned pupil anterior uve
- associated with alkalising spondylitis
- koeppe’s nodules at pupillary margins
- busacco’s nodules on surface of iris
— due to aggregation of epitheloid and mononuclear cells
Slit lamp microscope to check anterior chamber
DOC for ant uveitis?
DOC for Acute attack of ant uveitis?
1- Steroids
2- cycloplegics (for pain relief since it’s acute condition)
Atropine used
Longest acting cycloplegic
Atropine- used in children
Shortest acting cycloplegic
Tropicamide - used in adults
Intermediate uveitis
- candle wax dripping sign
- snowball/ snow banking sign
-DOC- steroids
Posterior uveitis
- choroiditis
In active form - headlight in the fog appearance- hazy posterior segment + bright optic disc
- MCC - toxoplasmosis
Bilateral granulomatous Panuveitis
Sympathetic opthalmitis
MCC- penetrating injury at the cilliary body
Treatment of choice- enucleation
