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4.5. Neurology and SS > 2. Internal Eye > Flashcards

2. Internal Eye Flashcards

1
Q

What are the causes and pathophysiology of anterior uveitis

A

Ae = idiopathic, ank spond, sarcoid, IBD, reactive arthritis, herpes, TB, syphilis

Path =

  • Anterior: iris + ciliary body (IRITIS)
  • Posterior: choroid (CHOROIDITIS)
  • Intermediate: vitrous + panuveitis
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2
Q

How does anterior uveitis present?

A

S+S =

  • red eye
  • pain
  • blurred vision
  • photophobia
  • in lacrimation (no sticky discharge)
  • small pupil from iris spasm
  • irregular pupil dilation due to synechiae (adhesion of lens + iris)
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3
Q

How should anterior uveitis be investigated and managed?

A

Ix = slit lamp with dilated pupils (leucocytes in anterior chamber)

Mx = urgent eye clinic, control underlying disease, pred drops, cyclopentolate (prevent spasm + synechiae)

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4
Q

What is the retina?

A

Receives light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition

Outer pigmented layer (in contact with choroid) + inner sensory layer (contact with vitreous), centre of the posterior part lies the macula

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5
Q

Outline the types of retinal detachment and their causes

A

1) rhegmatogenous retinal detachment
- tear in retina causes fluid to separate sensory retina from pigment ep
- trauma

2) exudative retinal detachment
- detaches without tear
- HTN, vasculitis, macular degenerative conditions

3) tractional retinal detachment
- pulling on the retina
- proliferative retinopathy

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6
Q

How does retinal detachments present?

A

4 Fs =

  • Floaters
  • Flashes
  • Field loss (central vision lost if macula detached)
  • Fall in acuity

***painless and may be curtain falling over vision

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7
Q

How should retinal detachment be Ix and Mx?

A

Ophthalmoscopy = grey opalescent retina, ballooning forward, extensive detachment will pull off the macula

Mx = rest, lie flat if detachment superior, lie 30 degrees heads-up if detachment inferior, laser photocoagulation therapy, vitrectomy and gas tamponade, scleral silicone implants

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8
Q

Outline central retinal artery occlusion

A

Occlusion is often thromboembolic (carotid A atherosclerosis)

  • much less common than retinal V occlusion
  • considered form of stroke

S+S = SUDDEN vision loss within seconds of occlusion, PAINLESS, signs of stroke (bruits, in BP), AF, heart valve disease, DM, smoking, in lipids

Ix =

  • USS carotids
  • Fundoscopy:
    • Central A = widespread oedema (retina white), cherry red spot in macula (still gets blood from underlying choroid)
    • Branch = localised area of retinal oedema

Mx = in retinal blood flow, reduce IOP by ocular massage, surgical removal of aqueous from anterior chamber, intraocular hypotensive Tx

  • Mx thromboembolic RF
  • Refer to stoke team for full work-up
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9
Q

Outline relative afferent pupillary defect (RAPD)

A
  • sign observed during swinging-flashlight test
    1) light directed in affected eye causes mild constriction of both pupils (due to decreased response to light from afferent defect)
    2) light in unaffected eye causes normal constriction of both pupils (due to intact efferent path, and intact consensual pupillary reflex)

Ae = INCOMPLETE optic N lesion: glaucoma, MS, optic neuritis, optic N tumours (glioma, meningioma), trauma, retinal detachment

  • Mild = weak pupil constriction, followed by dilation
  • Moderate = pupil size will remain, after which it dilates
  • Severe = pupil will dilate quickly
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10
Q

Describe amblyopia

A

Eye fails to achieve normal visual acuity

‘lazy eye’ = brain fails to process inputs from one eye and over time favours the other eye, results in decreased vision

Ae = any condition that interferes with focusing (poor alignment, irregularly shaped, nearsighted or farsighted, clouding of the lens)

Mx = treat underlying cause, glasses, eye patch (works until 7/8y)

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11
Q

What terminology is used to describe strabismus?

A

Squint - eye misaligned

ESO - turning in
EXO - turning out
Hyper - up
Hypo - down

Concomitant - amount of diversion remains constant in all directions of gaze
Inconcomitant - angle of squint varies with gaze (tend to be CN palsy)

Phoria - eye deviate only when fusion blocked (latent) (SOMETIMES)
Tropia - visual axis of each eye do not intersect at point of fixation (manifest) (ALWAYS)

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12
Q

How should strabismus be Ix?

A

Orthoptic assessment

Fundus

Bloods

Scan

Hirschbergs Test = looking for light reflection to fall in the centre of the pupil, every 1mm is 7 degrees deviation

Cover Test

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13
Q

What are the causes of strabismus?

A

Congenital - within 6m (unknown)

Refractive errors - anisometropia (one eye v diff prescription to other), myopia, hypermetropia, astigmatism

Other - tumour (retinoblastoma), cerebral palsy, down syndrome

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14
Q

How should strabismus be Mx?

A

Patching good eye (reduce amblyopia) - improves vision not the squint (corrected later with surgery)

Specs (+/- prisms)

Surgery (muscle resection, recession)

Tx underlying cause

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15
Q

Outline CN IV (4) palsy

A

Innervates superior oblique (SO) muscle

S+S =

  • Lose of normal action = eyeball held extorted, up + in
  • Compensate by tilting head to contralateral side
  • Report diff looking down medially (walking down stair, reading) - diplopia worse
  • Diplopia (when head straightened from tilt)
  • hypertropia (superior oblique not pulling down, sits higher up)
  • WOOG (hypertropia worse on opposite gaze)
  • BOOT (better on opposite tilt)

Ae = vasculopathic, tumour, congenital, trauma, thyroid eye disease

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16
Q

Outline CN VI (6) palsy

A

Innervated lateral rectus (LR)

S+S =

  • Unopposed pull of medial rectus muscle (esotropia)
  • Unable to Abduct eye on affected side
  • Diplopia - worst when looking to effected side

Ae = DM, HTN, stroke, acoustic neuroma (corneal sensation loss earliest sign), RICP

Ix = HbA1c, BP, ESR, MRI (younge pt, exclude SOL, demyelination), AChR Ab, MuSK Ab

Mx = prism, cover one eye (large deviation), review 4-6w

17
Q

Outline CN III (3) palsy (down and out syndrome)

A

Ocular muscles = SR, IR, MR, IO

  • Adduction + vertical eye movements reduced
  • DOWN + OUT position

Innervates levator palpebrae = loss = PTOSIS

Parasympathetic to sphincter pupillae = loss = dilation (MYDRIASIS)

  • PS fibre on the outside, compression from outside (tumour, aneurysm) will show dilation early (CT angiogram)
  • Reaction to light absent or reduced

Patient complains of diplopia if eye held open (assuming both eyes can see)

Can be painful

Ae =

  • Pupil involved = aneurysm (interpeduncular fossa - MRI), tumour
  • Pupil sparing = microvascular, GCA, MG, ischaemia (DM, HTN, hyperlipidemia)

Ix = AChR Ab, MuSK Ab, CTa

18
Q

What are the types of refractive error (visual impairment)?

A

MYOPIA (short sight) - light focused in front of retina

  • long axial length
  • high power cornea, average axial length
  • corrected with = concave lens (EXPANDS light before enter eye)

HYPERMETROPIA (long sight) - light focused behind retina

  • short axial length, average cornea
  • low power cornea, average axial length
  • corrected with = convex lens (CONVERGES light before enter eye)

ASTIGMATISM (burred at any distance) - light focused in front and behind

  • rugby ball shaped with 2 axis mean 2 images
  • corrected with = 2 lens (1 brings the image forward, 1 pushes the image back)

PRESYOPIA (old eye)

  • declining amplitude of accommodation with age
  • can be variable throughout the day
  • corrected with = reading glasses or bifocal/varifocals
19
Q

What are the common causes of visual impairment in diff age groups?

A

CHILDREN = optic atrophy, cataract, congenital glaucoma

ADULTS = DM retinopathy, uveitis, macula dystrophies

ELDERLY = cataract, glaucoma, ARMD

20
Q

How should suspected refractive error be Ix?

A

Pinhole screening test = improvement in vision indicates probable uncorrected refractive error
- width of ray of light reduced so size of image on retina reduces, so blur reduced

21
Q

How should visual impairment be managed?

A

Focus = lenses that correct refraction

Distance vision = telescope devices

Reading vision enhancement = optical devices

Near vision enhancement = electronic devices

22
Q

Outline an afferent pupillary defect

A

Complete optic N lesion

S+S =

  • affected pupil stim: neither eye reacts
  • normal pupil stim: both eyes react
  • involved eye is blind
23
Q

What is adie’s (tonic) pupil

A

Ae = viral infection, trauma, vasospasm due to migraine, ocular surgery, tumour

Path = damage to parasymp fibres innervating pupil constrictor muscle with cell bodies in the ciliary ganglion

S+S = pupil abnormally dilated at rest, poor/sluggish pupillary constriction in bright light

24
Q

What are the 4 common causes of unequal pupil?

A

SMALL

  • Horners syndrome
  • Tonic pupil

LARGE

  • 3rd N palsy
  • acute glaucoma
  • pharmacological pupil
  • Holmes Adie pupil
25
Q

Outline a blowout fracture

A

Ae = trauma to the eye/orbit

Path = sudden pressure increase fractures orbit floor, contents prolapses into maxillary sinus

S+S = periorbital swelling, pain, double vision (esp on vertical gaze), impaired vision, anaesthesia over affected check (upper teeth, gums - infraorbital nerve injury), inability to move the eye up/down (inferior rectus entrapment)

Ix =

  • x-ray: tear drop sign, fluid level
  • CT: blood/orbital contents in sinus

Mx = nasal decongestants, Abx, oral corticosteroids, surgery

26
Q

Outline central retinal vein occlusion

A

Path = when an artery crosses a vein they share the same adventitial sheath, if the artery with stronger walls becomes occluded, it squeezes the vein, burst, oedema, blocks light from retina

RF = HTN, hyperlipidaemia, DM, hypercholesterolaemia, smoking, hypercoag, polycythemia vera, OCP

S+S = sudden unilateral blurred vision

Ix =

  • Fundoscopy: scattered haemorrhages (blood leaking between N ganglion layers), wide dilated vessels
  • Fluorescein angiography: marked delay in transit time

Mx = RF management

27
Q

Outline posterior vitreous detachment

A

Ae = normal physiology >55y, trauma
- myopic pts = more likely to get retinal detachment due to retinal deterioration

S+S = floaters, flashing lights

Mx = laser

Comp = retinal detachment, retinal tears, vitreous under the retina

4.5. Neurology and SS (17 decks)

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