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Flashcards in Disorders of the Retina Deck (53)
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1

What does a slit lamp examine?

Anterior of the eye
-everything is reversed

2

What does an ophthalmoscope examine?

Posterior of the eye
-Everything right way up and round
-Bit like looking through a keyhole through

3

What does biometry do?

Measures shape and size of eye.
Commonly used to calculate power of the intraocular lens implants for cataract and refractive surgery

4

What does perimetry do?

Systematic measurement of visual field

5

What does a fundus camera do?

Takes a photo of the back of the eye (retina).
Like a large ophthalmoscope with a camera attached

6

What is optical coherence tomography?

Optical Coherence Tomography, or ‘OCT’, is a technique for obtaining sub-surface images of translucent or opaque materials at a resolution equivalent to a low-power microscope. It is effectively ‘optical ultrasound’, imaging reflections from within tissue to provide cross-sectional images.

Allows you to look at the fovea as a cross section

7

What is Fluorescein Angiography?

Medical procedure where a fluorescent dye is injected into the bloodstream. The dye highlights blood vessels in the back of the eye so that they can be photographed.

8

Describe Fleurescin and its reaction with the Blood-Retinal barrier

85% bound to serum proteins
15% unbound "free"

Inner + Outer Blood-retinal barrer
(retinal capillaries + zonula occludens respectively)
-Impermeable to fleuroscein

Choriocapillaris
-Permeable only to "free" fluorescein

9

What light do you shine on the eye in Fluorescein angiography and what shines back?

Shine blue at the eye and green light given off

10

How do cones and rods differ?

Just cones at fovea
Cones more to do with central vision and colour

Rods more black and white and periphery of visual field

11

What does electrophysiology do?

Series of investigations recording electrical signals from the eye, optic nerve and brain in response to visual stimuli

12

What is an electroretinogram (ERG)?

Measures retinal function

Records action potentials within the retina.
Different waves measure different cells.
Can test both rods and cones

13

What is an electro-oculogram (EOG)?

Measures function of RPE and photoreceptors

Measures resting potential difference between the RPE and photoreceptors
-Max PD in light adapted eye
-Max PD in dark adapted eye

14

What is visually evoked potentials (VEP)?

Records optic nerve function

Measures electrical activity in the visual cortex in response to either a flashing light or a checker board pattern

15

What does reduced amplitude and latency in VEP indicate?

Reduced amplitude:
-Reduced cell number
-Ischaemic/traumatic optic neuropathy

Latency:
-Reduced cell function
-Optic neuritis (demyelination)

16

What methods can you use to detect retinal pathology?

Visual acuity, visual fields, colour vision, RAPD

Fundoscopy

Fleorescein angiography

Optical coherence tomography (OCT)

Electrophysiology

17

What is RAPD?

Relative Afferent Pupillary Defect

18

In optic nerve pathology what is usually the first aspect of eyesight to go?

Colour vision
(before visual acuity and visual fields)

19

What causes sudden painless loss of vision?

-Central retinal vein occlusion
-Central retinal artery occlusion
-Ischaemic optic neuropathy
-Stroke
-Vitreous haemorrhage
-Retinal detachment
-Sudden discovery of pre-existing unilateral LoV

20

What can cause Central Retinal Vein Occlusion (CVAO)?

Hypertension
Glaucoma
Hyperviscosity
Inflammation

21

What can cause Central Artery Occlusion (CRAO)?

Emboli (carotids/heart)
Inflammation

22

What are the two types of Ischaemic Optic Neuropathy?

Arteritic (AION)
Non-Arteritic (NAION)

23

What are the symptoms of Giant cell arteritis?

Headache
Scalp tenderness
Jaw claudication
Neck pain
Nausea/anorexia
Loss of vision

24

What is the cardinal feature of giant cell arteritis?

Raised inflammatory markers

25

What is the gold standard in diagnosis of giant cell arteritis?

Temporal artery biopsy

26

What are the symptoms and signs of optic neuritis?

-Pain on eye movements
(nerve becomes inflamed)
-Reduced vision
-Red desaturation
(loss of colour first, esp red)
-Central scotoma
-Relative afferent pupil defect
-Swollen optic disc

27

What conditions cause gradual painless loss of vision?

-Cataract
-Refractive error
-Age-related macular degeneration
-Open angle glaucoma
-Diabetic retinopathy
-Hypertensive retinopathy
-Inherited retinal dystrophies
-Drug-induced retinopathy

28

What is age-related macular degeneration?

Common:
-10% >65
-30% >75

Progressve loss of central vision

Risk factors:
-Age
-Smoking
-Poor diet

29

What are the two types of age-related macular degeneration?

Dry type (80-90%)
-Slow onset
-Atrophy

Wet type (10-20%)
-More aggressive
-Neurovascular membrane (blood and fluid)

30

Briefly describe diabetic retinopathy

Diabeted damages pericytes which make up the capillary walls.

Contents of blood vessels leak out. This can be fluid or lipids

Outpouching of capillaries (microaneurysms) along with lipid deposits may be seen