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MD4001 > Pathology of the eye > Flashcards

Pathology of the eye Flashcards

1
Q

State the inverse care law.

A

The availability of good medical care tends to vary inversely with the need for it in the population served.

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2
Q

Identify the leading causes of blindness/Severe Sight Impairment worldwide. What proportion of blindness is avoidable or treatable ?

A
  • Cataract (number 1 cause)
  • Uncorrected refractive error
  • Age-related macular degeneration (main cause in developed countries)
  • Diabetic retinopathy
  • Glaucoma
  • Corneal opacities

80% is avoidable or treatable

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3
Q

Identify the main pathologies of the anterior segment of the eye.

A
  • Cataract (i.e. opacification of lens)

- Corneal ulcer

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4
Q

How are corneal ulcers treated ?

A

Antibiotic

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5
Q

Identify risk factors of cataracts.

A
  • Age
  • Diabetes
  • Trauma (or anything that touches the lens)
  • Inflammation (e.g. uviitis)
  • Steroid use
  • UV/Radiation
  • Congenital
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6
Q

Identify corneal ulcer risk factors.

A
  • CONTACT LENSES (hence don’t sleep, swim, shower with lenses)
  • Varicella/Herpes (because reduces corneal sensitivity long term)
  • Steroid drop use (immunosuppresant)
  • Dry eyes/Exposure (surface more vulnerable to infection)
  • Trauma/Burns (may expose eye)
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7
Q

Describe presentation of a corneal ulcer.

A 
Sore eye
Injected eye  (red eye)
Watering
Hypopyon
(Epithelial defect, can be stained to show)
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8
Q

What is the relation between corneal ulcer and keratitis ?

A

Keratitis (e.g. due to contact lens) can lead to corneal ulcer

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9
Q

Identify the main treatments for cataracts.

A

Surgery

1) MSICS- mot common form, in middle to low income countries
2) Phaecoemulsification (initial incision through cornea, no need for stitches)
3) Femtosecond laser

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10
Q

Why does abnormal red reflex occur (in general) ?

A

Anything obstructing the path of light from the front to the back of the eye

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11
Q

Identify different causes of abnormal red reflex.

A
  • Retinoblastoma (leucocoria = white red reflex)
  • Congenital cataract (black lines)
  • Corneal scar
  • Vitreous hemorrhage
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12
Q

Describe the genetics of retinoblastoma.

A
  • Knudson ‘2-hit’ hypothesis
  • RB1 - tumour suppressor gene
  • Hereditary - earlier, bilateral (because only need to acquire one more mutation to get disease)
  • Non-hereditary - later, unilateral
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13
Q

True or false: every newborn gets a red reflex check.

A

TRUE

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14
Q

Identify the main types of ophthalmoscopy.

A

DIRECT OPHTHALMOSCOPY
-Arclight

INDIRECT OPHTHALMOSCOPY

  • Slit lamp
  • Binocular indirect ophthalmoscope
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15
Q

Identify conditions of the posterior segment of the eye.

A
  • Diabetic retinopathy
  • Retinopathy of prematurity
  • Age-related macular degeneration
  • Swollen disc
  • Cupped disc
  • Glaucoma
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16
Q

How does diabetic retinopathy lead to blindness ?

A

Blindness due to:
• Growth of new vessels; they bleed (vitreous haemorrhage), and may cause tractional retinal
detachment (once they have fibrosed) and rubeotic glaucoma
• Diabetic maculopathy: Leakage of fluid from damaged vessels; macular oedema with loss of central visual acuity

17
Q

Define rubeotic glaucoma.

A

“VEGF makes tiny blood vessels grow, which we call ‘new blood vessels’. As the drain of trabecular meshwork in the anterior chamber is blocked, the aqueous is trapped in the eye putting the eye pressure up. This may cause corneal oedema”

Blinding + Painful

18
Q

Describe treatment of diabetic retinopathy.

A
  • Lifestyle – smoking, weight, exercise
  • Blood sugar/pressure/cholesterol
  • Support renal function
  • Laser, anti-VEGF, surgery
19
Q

Identify an imaging technique to view the posterior segment of the eye.

A

OCT (Optical coherence tomography)

20
Q

Describe pathogenesis of diabetic retinopathy.

A

In general, diabetes –> Biochemical mechanism –> Microvascular damage –> Mechanical processes –> Retinopathy

Increased glucose leads to:

  • Non-enzymatic glycation
  • Oxidative/reductive stress
  • Aldose-reductase activation
  • Diacylglycerol-proteinkinase C activation

All of these then result in microvascular endotheliopathy, which in turn leads to:

  • Increased permeability
  • Capillary occlusion
  • Neovascularisation

All of which lead to retinopathy

21
Q

How does retinopathy of prematurity arise ?

A

Similar pathological mechanism to diabetic retinopathy: when babies are born before retina is vascularised, hypoxic area of retina demands oxygen but nothing to supply with oxygen, so get VEGF creating new useless blood vessels that
can bleed and form ridge around the edge, causing retinal detachment which will cause blindness if untreated.

22
Q

Which epidemic of premature retinopathy are we currently experiencing ?

A

Third epidemic in middle-income countries

23
Q

Describe treatment for retinopathy of prematurity.

A
  • Laser peripheral retina, obliterating it, to stop oxygen demand from occurring.
  • Injections with anti VEGF
24
Q

How can we prevent retinopathy of prematurity ?

A

Screening programme (exists in the UK)

25
Q

What is the most common cause of blindness in people aged over 65 in high-income countries ?

A

Age-related macular degeneration

26
Q

Identify the main types of AMD, along with their main characteristics and treatment.

A

Dry: thinning out of part of retina (no treatment)

Wet: leakage of BVs and bleeding, macular oedema (anti-VEGF treatment). Metamorphopsia may suggest wet AMD

Progressive reduction in visual acuity in both.
Rehabilitation may help alleviate symptoms for both.

27
Q

Describe prevention of age-related macular degeneration.

A

Vitamin supplements may help prevent it

28
Q

Describe treatment of diabetic retinopathy.

A
  • Lifestyle changes: stop smoking, weight control, exercise
  • Glycemic control
  • BP control
  • Dyslipidaemia control
  • Support renal function (ACE inhibitors)
  • Laser (sacrifice peripheral retina to reduce oxygen demands as a whole for retina, thereby decreasing oxygen demands as a whole for retina, thus decreasing amount of VEGF produced, to reduce hypoxic drive which causes diabetic retinopathy to happen)
  • AntiVEGF injections
  • Surgery (blood leakage into vitreous from new BVs, remove bleeding, take vitreous out and replace with oil or gas via vitrectomy)
29
Q

Identify the main kinds of discs, in physiology and pathology.

A
  • Normal
  • Swollen
  • Cupped (thinned neuroretinal rim)
  • Pale (due to optic neuropathy, atrophy present)
30
Q

Identify causes of a cupped disc.

A

Cupped disc is sign of glaucoma (optic neuropathy, characteristic visual field defect, mostly commonly associated with raised IOP)

31
Q

Identify causes of swollen disc.

A

PSEUDOSWOLLEN

  • Small disc
  • Drusen (Calcium deposits)

GENIUINE SWELLING (Papilloedema)

  • Raised ICP
  • Possible SOL
  • IIH
  • Hydrocephalus
32
Q

Describe a typical presentation of swollen disc.

A

Headaches, especially when bending forwards (frontal); vomiting/nausea; visual disturbance; tinnitus; confusion; pupillary abnormalities; diplopia

33
Q

Describe timeline of presentation with glaucoma.

A

Patients unaware of visual field deficit until advanced disease, so may present late

34
Q

Describe treatment of glaucoma.

A

Drops (inflow reduction + outflow increase) or surgery (outflow increase)

35
Q

What is simultagnosia ? When might it arise ?

A

“Inability of an individual to perceive more than a single object at a time”

36
Q

Identify the main extra-ocular muscles.

A
  • 2 horizontal recti (medical and lateral)
  • 2 vertical recti (superior and inferior)
  • 2 oblique (superior and inferior)
37
Q

Describe the main features, causes, and investigations of a third nerve palsy.

A

Vertical diplopia; Eye is ‘down and out’; Diplopia everywhere; Pupil dilated and ptosis;

CAUSES
Can be associated with an aneurysm, a tumor, or it may be vasculopathic– needs urgent brain imaging and angiogram.

38
Q

Describe the main features and causes of a fourth nerve palsy.

A

Oblique diplopia; Head tilt away from side of the lesion; Diplopia worse away from the side of the palsy if unilateral (adduction);

CAUSES
Common after head injury; Bilateral - might be congenital.
Can also result from tumor, or can be vasculopathic.

39
Q

Describe the main features of a sixth nerve palsy.

A

Horizontal diplopia; Worse in far distance; Worse towards the side of the palsy if unilateral;

CAUSES
Bilateral - concerned that raised intracranial pressure is present.
Can result from tumor, or can be vasculopathic.

MD4001 (74 decks)

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