OPTH - Eyes review Flashcards

1
Q

When should you try pinhole in a visual acuity test?

A

if VA 6/9 or worse

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2
Q

What is Marcus Gunn Pupil?

A

Relative Afferent Pupil Defect

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3
Q

What is Agyll Robertson Pupil?

A

Pupil constricts on accomodation (when focussed on an object close-up) but NOT to light.

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4
Q

What is Holmes Adie Pupil?

A

–Tonically dilated pupil that does not react to light

–Associated with damage to parasympathetic pupillary fibres

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5
Q

What are the 3 things you should examine in an eye?

A
  1. vision
  2. pupils
  3. pressure
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6
Q

What is scotoma?

A

Blind spot in vision

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7
Q

What is metamorphosia?

A

distortion of vision

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8
Q

Positive findings in Amsler grid usually indicate (what)?

A

macular pathology

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9
Q

Abnormal EOM may indicate:

A
  • Cranial Nerve Palsy (CN III, IV or VI)
  • Muscle entrapment (orbital fracture)
  • Muscle infiltrate (Thyroid Eye Disease)
  • Muscle Weakness (i.e. Guilian-Barre Miller-Fisher variant)
  • Gaze Centre Dysfunction (horizontal gaze palsy, INO)
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10
Q

What is the most common cause for poor vision in humans?

A

Refractory error

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11
Q

Compare myopia & hypermetropia

A

Myopia: short sighted

  • longer eye
  • steeply curving cornea
  • light is focused BEFORE hitting the retina
  • Rx: concave lens to diverse light

Hypermetropia: long sighted

  • shorter eye
  • gradual curving cornea
  • light is focused AFTER hitting the retina
  • Rx: convex lens to converge light
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12
Q

What structures focus the light onto the retina in a normal eye?

A

Cornea (67%) & Lens (33%)

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13
Q

What is the fastest way to detect refractive error?

A

Pinhole

Pinhole obscures the light which has been inappropriately focussed onto the retina

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14
Q

What is presbyopia?

A

long-sightedness caused by loss of elasticity of the lens of the eye, occurring typically in middle and old age.

Rx: reading glasses/bifocals

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15
Q

Describe cataract

  • Px
  • causes
  • Rx
A
  • Gradual decrease in visual acuity and increase in glare symptoms (over weeks to years)
  • age-related, steroids, trauma, DM, Wilson’s diseae, ocular diseases (uveitis etc)
  • Rx: cataract surgery.
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16
Q

Describe logistics of cataract surgery

A
  • Visual improvement in >95% of operations performed
  • Patients often admitted as a day-case
  • Usually performed under topical or local anaesthesia
  • Patient must be able to lie flat and still
  • Post-operative antibiotic and steroid eye drops over 4 weeks
  • Post-operative reviews: 1 day, 1 week, 1 month
17
Q

What are the 3 major clinical features of primary open angle glaucoma (POAG)?

A
  1. Progressive visual FIELD loss
  2. Progressive increase in cup-to-disc ratio of optic disc.
  3. Elevated intra-ocular pressure

Note:

  • Some people have high IOP but no evidence of glaucoma (Ocular Hypertension)
  • Some people have features of glaucoma despite normal IOP (Sometimes referred to as Normal Tension Glaucoma)
18
Q

Rx of primary open angle glaucoma (POAG)

A
  • carbonic anhydrase inhibitors. E.g. Acetazolamide (Diamox) to decrease aqueous production
  • Alpha agonist

Laser:
- selective laser trabeculoplasty

Surgical:
- Trabeculectomy (alternative drainage path for aqueous)

19
Q

Compare uveitic glaucoma & neovascular glaucoma

A

Uveitic Glaucoma:
- Synechiae and inflammatory cells effect fluid dynamics within the anterior chamber

Neovascular glaucoma:

  • Neovascularisation of the angle leads to reduced drainage of aqueous humor and increased intra-ocular pressure.
  • Neovascularisation occurs secondary to ischaemia within the eye (e.g. in setting of CRVO or proliferative diabetic retinopathy)
20
Q

What are the 2 types of diabetic retinopathy?

A

Non-prolifeative & proliferative

21
Q

How do you grade non-proliferative diabetic nephropathy?

A
  1. Mild: microaneurysms
  2. Moderate:
    - microaneurysms
    - intraretinal haemorrhages
    - hard exudates
    - cotton wool spots
  3. Severe (any one of the 4-2-1 rule)
    - intraretinal haemorrhages in 4 quadrants
    - venous bleeding in 2 quadrants
    - intraretinal vascular abnormalities in 1 quadrant
  4. Very severe
    - 2 features from the 4-2-1 rule
22
Q

Rx of proliferative diabetic retinopathy

A

Panretinal photocoagulation (laser)

  • burns away areas of peripheral retina
  • stops vessels on the retina from leaking
  • decreases drive of BEGF production -> reduced neo-vascularisation
23
Q

What is glaucoma? Describe briefly the 2 main categories.

A

a group of ocular (eye) disorders that result in optic nerve damage, often associated with increased fluid pressure in the eye (intraocular pressure) (IOP).

2 main categories: “open-angle” and “closed-angle” (or “angle closure”) glaucoma.

Open-angle chronic glaucoma

  • painless
  • develop slowly over time
  • often asymptomatic until the disease has progressed significantly.
  • Rx: glaucoma medication to lower the pressure, or with various pressure-reducing glaucoma surgeries.
Closed-angle glaucoma:
- sudden eye pain
- redness
- nausea and vomiting
- other symptoms resulting from a sudden spike in intraocular pressure
= medical emergency.
24
Q

Describe diabetic maculopathy (compare macular oedema & macular ischaemia)

  • Causes
  • Rx
A
  1. Macular oedema
    - leakage of fluid into foveal tissue
    - lipid exudates adjacent to fovea
    - Rx: macular (grid) laser, intravitreal anti-VEGF agents
  2. Macular ischaemia
    - capillary non-perfusion at fovea
    - enlarged foveal avascular zone & capillary drop out on fluorescein angiography
    - Rx: none. Control BSL, BP, cholesterol.
25
Q

Describe macular degeneration (compare dry & wet)

  • causes & risk factors
  • Rx
A
  1. Dry age-related macular degeneration
    - Most common cause of blindness in people >50 in the developed world
    - Risk factors: age, smoking
    - Rx: quit smoking, low vision aids
  2. Wet (neovascular) age-related macular degeneration
    - Choroidal neovascularisation (classic feature)
    - abnormal new vessels grow from choroid to retinal pigment epithelium
    - vessels leak/bleed -> macular scarring
    - linked to increased VEGF
    - Rx: anti-VEGF agents (ranbizumab, bevacizumab) via intraocular injection, photodynamic therapy, macular laser
26
Q

Describe CN III palsy

  • Px
  • cause
  • Ix
  • Rx
A
  • “down and out” +/- mydriasis

Causes

  • compressive (tumour, haemorrhage, aneurysm): commonly pupil involving (mydraisis)
  • vascular (HTN, DM): commonly pupil sparing
  • trauma
  • giant cell arteritis

Ix:
- MRI/MRA, BP, BSL, lipid profile

Rx: depends on cause

27
Q

Describe CN IV palsy

  • Px
  • cause
  • Ix
  • Rx
A

“tip, turn and tilt”

Causes:
- trauma, tumour, vasculitis (GCA), microvascular disease

Ix:
- old photos for congenital, bloods, neuroimaging

Rx:

  • according to cause
  • prism in glasses
28
Q

Describe CN VI palsy

  • Px
  • cause
  • Ix
  • Rx
A

“Look left”

Causes:
- vascular, raised ICP, tumours, trauma, GCA

Ix: vascular risk factors, MRI

DDx:

  • thyroid eye disease
  • medial wall blow out fracture

Rx:

  • according to cause
  • Prisms +/- strabismus surgery