Vision 1 Flashcards

0
Q

What is the lens made of?

A

Lens fibres (annuclear)
stem cells
core
surrounded by a capsule

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1
Q

What does 70% of focusing?

A

The cornea

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2
Q

What is the protein in the lens called?

A

Crystallin

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3
Q

What attaches to the capsule if the lens?

A

Suspensory ligaments

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4
Q

What occurs during short focus?

A

Ciliary muscle contracts
Ciliary body is moved forwards
Suspensory ligaments slackens
Lens rounds up

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5
Q

What is the medical name for long sightedness?

How do you fix this?

A

Hypermetropia

Eyeball too short

Corrected with converging lens

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6
Q

What is the medical term for short sightedness?

Fix?

A

Myopia (me!)

Eyeball too long

Corrected with diverging lens

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7
Q

What is the term used to describe the thickening & hardening of the lens with age?

A

Presbyopia

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8
Q

Define ‘astigmatism’

A

‼️

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9
Q

What does LASIK stand for?

A
Laser
Assisted
In
Situ
Keratomileusis
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10
Q

What does PRK stand for?

A

Photo refractive keratectomy

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11
Q

In the lens, what do fibre cells have a high content of?

A

Protein

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12
Q

List causative factors if cataracts

A

Age
Diabetes
Enzyme deficiencies

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13
Q

What is phototransduction?

A

The response if photo receptors to light

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14
Q

Name 2 photoreceptors

A

Rods & cones

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15
Q

What consists the outer segment of photoreceptors?

A

Modified cilium

16
Q

How does the energy from photons effect the membrane lipids in photoreceptors?

A

Oxidise
Damage
Discs must be renewed

17
Q

In the dark, what triggers the opening of ion channels in discs?

A

cGMP build up in rods & cones

18
Q

What absorbs light in the disc?

A

Opsin

19
Q

In light, what breaks down the cGMP to GMP?

A

Transducin

20
Q

What are the 3 cone photopigments (opsins)?

A

Blue, green, red

21
Q

What chromosome is mutated in colour blindness?

A

X

More common in men