4.1.1 The Retina Flashcards

1
Q

What are the 3 layers of the eye?

A

Sclera- continuous with the dural sheath of optic nerve

Uvea- choroid and lens / ciliary body anteriorly

Retina- pigmented and neural layer

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2
Q

Label the image

A
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3
Q

What does the pigmented layer do?

A

Absorbs excess light to prevent light from scattering in the eye causing a glare

Determines amount of light that gets to the retina

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4
Q

Why can albinos develop photophobia?

A

Reduced pigment in the eye, this leads to light rebounding in the eye causing a glare

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5
Q

What do photoreceptor cells do?

A

Rods and Cones

Rods- Black and white vision, active at low light intensity e.g. at night

Cones- colour vision, active at high light levels

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6
Q

What do horizontal cells do?

A

Lateral inhibition leading to higher definition at the edges and increased contrast, inhibitory interneurones

Prevents too many neural impulses

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7
Q

What do bipolar cells do?

A

First order neurones

Act to connect photoreceptor cells to retinal axons

Collect information and interact with retinal ganglion cells

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8
Q

What can be found on fundoscopy?

A

Retinopathies
-Hypertension
-Diabetes

Vascular occlusions
-Branch of central retinal artery or vein
-Amaurosis fugax

Macula
-Degeneration

Optic disc
-Papilloedema

ROMV

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9
Q

Image of normal retina

A
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10
Q

What are some features about the fovea?

A

-Highest density of photoreceptors
-Rich cone content
-Thin, dips therefore, reduced impediment of light to reach cones

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11
Q

What happens at the optic disc?

A

Vessels all converge here
Where retinal axons coalesce to form the optic nerve
Optic nerve exits here

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12
Q

What happens in retinal detachment?

A

Photoreceptors separate from the underlying pigment epithelium

Fluid builds up between the layers

Separation of neural layer from pigmented layer

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13
Q

What are some symptoms of retinal detachment?

A

Sudden blurring
Vision loss
Visual artefacts

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14
Q

What is amaurosis fugax?

A

Painless loss of vision due to central retinal artery occlusion

Described as curtain coming down over you

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15
Q

What can be used to visualise the layers of the retina?

A

Optical Coherence Tomography OCT

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16
Q

Label the image

A