130 - Sudden Visual Disturbance Flashcards Preview

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Flashcards in 130 - Sudden Visual Disturbance Deck (64):
1

What is the term given to constriction of the pupil?

Miosis

1

What problems with the lens can cause vision disturbance?

  • Loss of clarity
  • Acute cataract - think diabetes
  • Dislocation through trauma or Marfans

 

2

What is Fuch's dystrophy?

  • Autosomal dominant condition
  • Slowly progressing disease - glare and blurring
  • Corneal oedema and vision loss
  • Loss of endothelial cells
  • Thickening of Descemet's membrane
  • Can also be triggered by cataract surgery

2

Which gene has been linked to retinoblastoma and which chromosome is it found on?

Retinoblastoma gene on Chromosome 13

3

Describe closed angle glaucoma

  • Angle is narrowed
  • Iris obstructs trabecular network/ canal of Schlemm

4

What posterior chamber problems can cause vision distubance?

  • Loss of clarity
  • Blood
  • Pus
  • Vitreous detachment
  • Retinal detachment

4

Describe the Acathomoeba infection of the eye

  • Caused by protozoa
  • It is normally found in soil and water
  • Can cause keratitis if contact lens hygeine is suboptimal

5

How many layers (laminae) are present in the lateral geniculate nucleus, and what does each do?

6 Laminae

  • 1 & 2 - magnocellular; movement and temporal contrast
  • 2-6 - parvocellular; colour, spatial contrast
  • 1-6 - Koniocellular; blue-yellow contrast

 

6

What are the 3 proteins found in the membranous discs of rod and membrane folds in cones?

  1. Visual pigment (retinal plus opsin)
  2. Transducin (G protein)
  3. cGMP phosphodiesterase

 

6

What happens to the 11-cis retinal molecule when hit by a photon?

It isomerses to 11-trans retinal which is freely diffuses along the membrane to activate multple molecules of transducin

7

Which division of the nervous system dilates the pupil and what is the term for this?

Sympathetic nervous system

Mydriasis

8

What are the symptoms of dorsal midbrain syndrome?

Light near dissociation:

  • Light causes no reaction to the pupil
  • Near response causes the pupils to constrict

Failure of upgaze

Nystagmus

9

What is a condition can commonly cause a relative afferent pupillary defect?

Retrobulbar neuritis in multiple sclerosis

10

What are the symptoms of giant cell arteritis?

  • Blurred vision or sudden blindness
  • Headaches
  • Tender, nodular, temporal artery

 

11

What is seen under the microscope in retinoblastoma?

Flexner-Wintersteiner rosettes

11

What is the immediate treatment of giant cell arteritis if it presents in an A & E setting?

High dose steroids to preserve sight

12

What is the main pathology of the uveal tract?

Malignant melanoma of the uveal tract

13

What is the best treatment for wet AMD?

Anti-VEGF therapy

 

15

What is the efferent limb of the pupillary light reflex made up of?

  • Edinger-Westphal nucleus
  • Oculomotor nerve
  • Ciliary ganglion
  • Short ciliary nerves
  • Sphincter pupillae

16

What structure keeps the lens under tension when focusing on objects in the far distance?

The zonule (lens ligament)

17

What are the main support cells found in the retina?

  • Muller's cells
  • Astrocytes

 

18

What conditions can cause secondary glaucoma?

  • Inflammation/ uveitis
  • Phacogenic (Cataract/ lens subluxation)
  • Trauma
  • Drugs such as steroids
  • Diabetes/ neovascular

19

What structures constitute the afferent limb of the pupillary light reflex?

  • Ocular media
  • Retina
  • Optic nerve
  • Optic chiasm
  • Optic tract
  • Pretectal nuclei

20

What are the main differences between dry and wet AMD?

Dry AMD:

  • Drusen and abnormalities of RPE (Retinal Pigment Epithelium)
  • Usually little impact on vision unless RPE atrophy develops

Wet AMD:

  • New vessel growth from the choroidal layer
  • Severe impact on vision

20

Describe herpes simplex keratitis

  • Corneal ulceration due to HSV (re-activation)
  • Dendritic ulcer
  • Causes blurred vision and pain

21

What cells do the axons of the optic nerve synapse with inside the lateral geniculate nucleus?

  • Magnocellular
  • Parvocellular

 

22

What are the 4 main groups of glaucoma?

  1. Chronic open angle
  2. Closed angle
  3. Developmental
  4. Secondary

 

23

What muscle contracts to relax the lens, allowing focusing on near objects?

The ciliary muscle

24

What is the effect of a single photon hitting a rod, in terms of ion channels?

It inhibits about 300 ion channels, altering the cells excitability

 

25

What cells are involved in transmitting a change in photoreceptor potential to the ganglion cells, both directly and indirectly?

Directly:

  • Bipolar cells

Indirectly:

  • Amacrine cells
  • Horizontal cells

 

26

What are the 2 main distributions of retinoblastoma and how are they different?

Inherited:

  • 1st year of life presentation
  • Bilateral tumours

Sporadic:

  • Present up to the age of 5
  • Unilateral tumour

 

27

Why must a squamous cell carcinoma-in-situ of the conjunctiva monitored/addressed?

It can progress into invasive squamous cell carcinoma.

 

29

Where do the majority of ocular trauma occur in the elderly and children?

In the home

 

30

Which muscles are responsible for convergence and which nerve innervates them?

Left and right medial rectus muscle

Innervated by Oculomotor nerve (CNIII)

30

How is an relative afferent pupillary defect tested for, and what would you see in a positive test?

Swinging light test

The pupil appears to dilate when a bright light is swung from the unaffected eye to the affected eye.

31

Which type of AMD is the most common?

Atrophic

 

32

What are the causes of dorsal midbrain syndrome (Parinaud's syndrome)?

  • Pineal tumour
  • Neurosyphilus
  • Multiple sclerosis

33

How does anti-VEGF therapy work?

It inhibits and reverses new blood vessel formation in the retina.

35

What are the symptoms of AMD?

  • Central vision distortion or missing
  • Loss of contrast sensitivity
  • Usually bilateral

 

36

What is giant cell arteritis?

It is an inflammatory disease of large and medium sized arteries, usually of the head and neck

37

What problems with the anterior chamber can lead to visual disturbance?

  • Loss of clarity/ volume
  • Blood (hyphaemia)
  • Trauma
  • Pus

 

38

What are the risk factors for glaucoma?

  • Age
  • Ethnicity; East Asian - closed angle, Afro Caribbean - open angle
  • Myopia
  • Family history
  • Diabetes mellitus

 

40

What is the main cause of a squamous cell carcinoma-in-situ of the conjuctiva?

UV light

40

What are the 5 layers of the cornea?

  1. Corneal epithelium
  2. Bowman's membrane
  3. Corneal stroma
  4. Descement's membrane
  5. Corneal endothelium

42

What are the 3 components of the near repsonse?

  1. Accommodation
  2. Constriction of the pupil
  3. Convergence of the eyes

44

Describe chronic open angle glaucoma

  • Trabeculae leading to canal of Schlemm blocked
  • Angle normal

45

What corneal problems can lead to sudden visual disturbance?

  • Loss of clarity
  • Acute pressure rise
  • Corneal infection

 

47

Where do the axons of the ganglion cells leave the eye and what effect does this congregation have on vision?

Optic disc

It produces the blind spot

48

What are the 2 type of AMD (Age related Macular Degeneration)?

  1. Atrophic (DRY)
  2. Exudative (WET)

 

49

What is the usual presenting symptom of a retinoblastoma?

Leukocoria (white reflex of eye)

50

Describe a cataract and its causes

It is opacification of the lens due to denaturation of its proteins.

Leads to loss of visual acuity and contrast

Caused by:

  • UV light
  • Other types of radiation
  • Trauma
  • Diabetes
  • Hypertension
  • Old age
  • Drugs such as steroids

 

51

What is the most common intraocular malignancy of children?

Retinoblastoma

 

52

Which cell in the eye is the first to produce an action potential in response to light?

The ganglion cells

53

What is the main pathological process involved in exudative AMD?

Subretinal neovascularisation 

54

What are the 10 layers of the sensory retina?

  1. Retinal pigment 
  2. Photorecptor layer
  3. External limiting membrane
  4. Outer nuclear membrane
  5. Outer plexiform layer
  6. Inner nuclear layer
  7. Inner plexiform layer
  8. Ganglion cell layer
  9. Nerve fibre layer
  10. Internal limiting layer (most superficial, inside eye)

55

What is the main cause of a developmetal glaucoma?

Congential glaucoma

 

56

Which part of the visual system do the nasal half of optic nerves decussate?

Optic chiasm

57

What nerve, and division of the nervous system are involved in contraction of the ciliary muscles?

The occulomotor nerve carrying parasympathetic nerve fibres

58

What are the signs of a squanmous cell carcinoma-in-situ- of the conjunctiva?

  • Thickened conjunctiva
  • Abnormal maturation with pleomorphism
  • High mitoses
  • Dyskeratosis

59

What arethe major sources of ocular trauma in young adults?

  • Sports
  • Assault
  • Work

60

What pathologies of the retina can lead to vision loss?

  • Detachment
  • AMD
  • Vascular occlusions; arterial & venous

 

62

Which part of the visual system is affected to produce a positive swinging light test?

Anywhere anterior to the optic chiasm

63

What are the clinical findings seen in giant cell arteritis?

  • Raised ESR (>60mm/hr)
  • Raised CRP

Under microscope:

  • Giant cells and chronic inflammation
  • Thickening of intimal layer with narrowing of lumen

64

Which brain structure is the lateral geniculate nucleus a part of?

Thalamus