Eyes Flashcards

1
Q

What makes the Cornea transparent ?

A

Regularly arranged collagen fibres
No blood vessels
AH pumped out via endothelial layer pumps

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2
Q

What is the first layer of the retina (outside) ?

A

Pigmented layer

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3
Q

What is the second layer of the retina (outside) and what is found there ?

A

Neural layer - rods and cones

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4
Q

What supplies the retina with blood ?

A

From the outside via the choroid and from the inside via the central retinal artery

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5
Q

What is lens opacification called ?

A

Cataracts

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6
Q

What predisposes the lens to becoming opacified ?

A

Avascular and exposure to UV rays

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7
Q

What can be used to visualise tear film ?

A

Fluroscein

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8
Q

Function of aqueous humor ?

A

Maintain IOP

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9
Q

Function of vitreous humor ?

A

Cushion and support the retina

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10
Q

What structures form from the side of the forebrain to make the eyes ?

A

Optic vesicles

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11
Q

What happens to the optic vesicles next ?

A

The grow towards the surface ectoderm and cause it to thicken forming the lens placode

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12
Q

What does the lens placode do ?

A

It invaginates and forms a pit. it eventually pinches off with the optic vesicle. The Optic cup is formed which houses the lens vesicle.

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13
Q

What is the choroidal fissure ?

A

Hole where blood vessels gain access to the optic cup and lens vesicle. It is found in the optic stalk.

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14
Q

What happens when the choroidal fissure closes ?

A

The vessels are enclosed in the optic stalk, they form the central retinal artery.

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15
Q

Corneal dystrophies

A
  • Central vision is lost
  • Run in families
  • Material builds up in the cornea
  • Bilateral
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16
Q

How do we treat corneal dystrophies ?

A
  • Corneal transplants

- Laser treatment (PTK)

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17
Q

Corneal degenerations

A
  • Peripheral vision lost
  • Unilateral
  • Usually seen with systemic diseases
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18
Q

Retinal detachment - what happens ?

A

VH goes between the pigmented layer and the neural layer causing detachment.

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19
Q

Retinal detachment symptoms

A
  • Flashing lights
  • Floaters
  • Vision loss/dark curtain
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20
Q

Coloboma

A

Hole in one of the structures of the eye. Affects vision differently depending on location

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21
Q

Glaucoma - What causes it ?

A

Raised IOP

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22
Q

Two types of Glaucoma

A

Primary Open Angle Glaucoma

Closed Angle Glaucoma

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23
Q

Symptoms of Primary Open Angle Glaucoma

A
  • Asymptomatic

- Peripheral vision is usually affected first.

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24
Q

Symptoms of Closed Angle Glaucoma

A
  • Painful
  • Loss of vision/blurred vision is immediate
  • Nausea and vomiting
  • Sore red eye
  • Eye is hard
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25
Q

Symptoms of Cataracts

A
  • Blurred vision
  • Difficulty seeing in dark
  • Sensitivity to bright lights
  • Fading of colours
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26
Q

What is the blood-occular barrier created by ?

A

Barrier between the endothelium of the capillaries in the iris, retina and ciliary body and the retinal pigment epithelium.

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27
Q

why is the blood ocular barrier important ?

A

Prevents substances from passing through into the eye from blood vessels.

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28
Q

What are the two parts of the barrier ?

A

1) Blood aqueous barrier - Ciliary epithelium and capillaries of the iris
2) Blood retinal barrier - Capillaries of the retina and the epithelium of the pigment layer

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29
Q

Retinal detachment - How is it treated ?

A

Surgery known as Pneumatic Retinopexy. A gas bubble is inserted which presses on the detached section pushing it back into place. A laser is they used to attach it firmly in place.

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30
Q

Hordeolum/Stye

A

Infection of the mebomian (internal) or sebaceous glands (external) of the eyelid.

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31
Q

Definition of refractive error

A

Problem focusing light accurately onto the retina due to the shape of the eye.

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32
Q

What is Retinitis Pigmentosa ?

A

Group of genetic disorders that involve the breakdown and loss of cells in the retina. Result in loss of peripheral vision and difficulty seeing at night.

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33
Q

What is Optic Neuritis ?

A

Inflammation of the optic nerve. Pain and temporary vision loss are common symptoms.

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34
Q

Electroretinography (ERG)

A

Electrodes are placed on the cornea and this allows you to record signals given off from photoreceptive cells in the retina to the brain in response to light.

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35
Q

Gene therapy - What and when ?

A

Used to replace missing or defected genes in the eye in order to correct genetic disorders. Used in Wet AMD and diabetic retinopathy currently.

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36
Q

Why do muscles of the eye have more than one function ?

A

They are attached in the orbital axis where as the eye is in the optical axis.

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37
Q

Definition of Phototransduction

A

Phototransduction is the process by which the absorbed light triggers an electrical response in rods and cones.

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38
Q

What are the steps of Phototransduction ?

A

When light falls on 11-cis retinol it isomerise to all-trans retinol. All-trans cannot fit in opsin/rhodopsin and so they split. Activated opsin/rhodopsin cause Na+ channels to close and this hyperpolarises the cell. Hyperpolarisation is transmitted via calcium ions. This ultimately stimulates the retina cell. AP triggered in optic nerve.

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39
Q

What role does vitamin A play in the visual pigment ?

A

Visual pigment regeneration

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40
Q

What happens if you are deficient in Vit A ?

A
  • Night-blindness

- Unhealthy conjunctiva and corneal epithelium

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41
Q

What are the first signs of Vit A deficiency ?

A

Bitot’s spots and Corneal Ulceration. Corneal melting occurs later on if deficiency isn’t rectified.

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42
Q

What causes colour blindness ?

A

Some cone cells are deficient or abscent and this means some people are unable to distinguish certain colours.

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43
Q

What part of the NS causes pupil constriction ?

A

Parasympathetic - Sphincter pupillae

44
Q

What part of the NS causes pupil dilation ?

A

Sympathetic - Dilator pupillae

45
Q

Definition of refraction

A

The bending of light as it passes through one medium to another

46
Q

What causes refraction in the eye ?

A

The cornea and lens mainly but also the AH and VH.

47
Q

What structure has the most powerful bending ability ?

A

The cornea (45D) compared to the lens (15D). The lens is able however to change its bending power.

48
Q

Which fibres cross at the optic chiasma ?

A

The nasal fibres that see the temporal fields.

49
Q

What is the MFL ?

A

Medial longitudinal fasciculus

50
Q

What does the MFL contain ?

A
  • Ascending and descending fibres from cranial nerves 3, 4, and 6 that control lateral and vertical gaze
  • Vestibular fibres that control eye movements in response to changes in head position.
51
Q

Where to the fibres of the pupillary reflex go to ?

A

They don’t go to the LGB but instead to the CN 3 nucleus in the midbrain. Part of the nucleus is the EWN which control parasympathetic response in both eyes.

52
Q

How do the parasympathetic fibres enter the orbit ?

A

They are carried on the outside of CN 3. They synapse in the ciliary ganglion then enter the eye via the short ciliary nerves.

53
Q

Is this response unilateral or bilateral ?

A

Unilateral

54
Q

What signs can be seen in the eye if the sympathetic chain is damaged ?

A

Anhydrosis
Ptosis
Miosis

55
Q

What is the conjunctiva ?

A

A thin vascular membrane that covers the surface of the eyelids and sclera. It doesn’t cover the cornea.

56
Q

What is conjunctivitis ?

A

Infection of the conjunctiva. Can be viral or bacterial.

57
Q

What are the symptoms of conjunctivitis ?

A
  • Red eye
  • Watery
  • Discharge
58
Q

How do you treat conjunctivitis ?

A
  • Antibiotic eye drops

- Good eye hygiene

59
Q

What do you call a corneal transplant ?

A

Keratinoplasty

60
Q

What lens in implanted to cure cataracts ?

A

Posterior Chamber Intraoccular Lens (PCIOL)

61
Q

Symptoms of Glaucoma

A
  • Raised IOP
  • Pale, unhealthy optic disk
  • Visual disturbances
62
Q

What is the topical management of PA Glaucoma ?

A
  • Beta blockers
  • Prostaglandin analogues
  • Carbonic anhydrase inhibitors
63
Q

What other techniques may be used if topical treatments for Glaucoma fail ?

A
  • Laser trapectuloplasty

- Trabeculectomy surgery

64
Q

Acute management for CA Glaucoma ?

A
  • IV carbonic anhydrase inhibitor
  • Pilocarpine
  • Analgesics
  • Anti-emetics
65
Q

What surgery is performed to treat CA Glaucoma ?

A

Laser Iridotomy

66
Q

What part of the eye does anterior uveitis affect ?

A

Iris +/- Ciliary body

67
Q

What part of the eye does intermediate uveitis affect ?

A

Ciliary body

68
Q

What part of the eye does posterior uveitis affect ?

A

Choroid

69
Q

How would patient present with Uveitis ?

A
  • Red eye
  • Painful to move
  • Hazy vision/floaters
  • Vision may be lost
  • Photophobia
70
Q

What is Optical Coherence Tomography used for ?

A

OCT is used to look at the layers of the retina

71
Q

What 3 conditions can result in sudden vision loss ?

A
  1. Central retinal vein occlusion
  2. Central retinal artery occlusion
  3. Optic Neuritis
72
Q

How do you treat a central retinal artery occlusion ?

A

Identify and treat risk factors

  • Reduce cholesterol
  • Reduce BP if high
  • Other medical conditions need to be under control
73
Q

How do you treat a central retinal vein occlusion ?

A
  • Identify and treat risk factors
    • Reduce cholesterol
    • Reduce BP if high
    • Other medical conditions need to be under control
  • Inject Intravitreal anti VegF to reduce swelling
74
Q

How does Optic Neuritis caused by Giant Cell Arteritis present (4) ?

A
  • Jaw claudication
  • Scalp tenderness
  • Vision loss
  • Headaches
75
Q

How do you treat Giant Cell Arteritis ?

A

High dose prednisolone

76
Q

How do you treat Non-Arteritic Optic Neuritis ?

A

Identify and treat risk factors.

  • Reduce cholesterol
  • Reduce BP if high
  • Other medical conditions need to be under control
77
Q

What is age related macular degeneration ?

A

Lose central vision and a distorted image develops

78
Q

What can be seen changing in the eye ?

A
  • The pigment epithelial

- Drunsen appears

79
Q

What are the two types of AMD ?

A

Wet and Dry

80
Q

What occurs in Dry AMD

A
  • Drunsen

- Atrophy

81
Q

How do you manage Dry AMD ?

A
  • Low vision aids

- Registration

82
Q

What occurs in Wet AMD ?

A
  • New choroidal vessels
83
Q

What Investigations should be done to confirm Wet AMD ?

A

Fluroscein angiography and OCT

84
Q

How do you treat Wet AMD ?

A
  • Intravitreal anti VegF
  • Low vision aids
  • Registration
85
Q

What happens to the eye in Diabetic Retinopathy

A
  • Haemorrhages
  • Exudates
  • Neovasculation
  • Microaneurysms
86
Q

What investigation should be done to confirm Diabetic Retinopathy ?

A

Fluroscein angiography and OCT

87
Q

How do you treat Diabetic Retinopathy ?

A
  • Intravitreal anti VegF
  • Low vision aids
  • Registration
  • If young you would start giving anti VegF, carry out Laser-Panretinal Photocoagulation
88
Q

What systemic conditions may cause retinal degenerations ?

A
  • Lupus
  • Diabetes
  • Rhematoid Arthritis
89
Q

How do patients present with allergic conjunctivitis ?

A
  • Sore red eye
  • Itching
  • Watery eyes
  • Swelling
90
Q

How do you treat patients with allergic conjunctivitis ?

A
  • Topical antihistamines
  • Avoid the antigen
  • Mast cell stabilisers
91
Q

What will a patient present like who has a corneal abrasion ?

A
  • Painful
  • Watery eye
  • Blurred vision
  • Red eye
92
Q

How do you treat patient with a corneal abrasion ?

A
  • Analgeics

- Topical antibiotics

93
Q

How do you treat a patient with Anterior Uveitis ?

A
  • Oral Corticosteroids

- Mydriatic eye drops

94
Q

What is a Hypopyon ?

A

It’s a condition involving inflammatory cells in the anterior chamber of the eye. Exudative.

95
Q

How do you treat a Hypopyon ?

A
  • Oral Corticosteroids

- Mydriatic eye drops

96
Q

How do patients present with Scleritis ?

A
  • Red eye
  • Watery
  • Painful
97
Q

How do you treat Scleritis ?

A

Give stystemic steroids

98
Q

What is Orbital Cellulitis ?

A

Infection/inflammation of the tissues surrounding the eye.

99
Q

How does a patient present with Orbital Cellulitis ?

A

Patient will present with symptoms of infection e.g. fever, malaise. They may have a sore, red eye and complain of double vision.

100
Q

How do you treat a patient with Orbital Cellulitis ?

A
  • IV antibiotics
  • CT scan
  • Drainage of pus
101
Q

Which two eye conditions result in the most people globally being visually impaired ?

A

Cataracts and refractive error

102
Q

What factors stop people seeking medical help ?

A
  • Hard to access
  • Poor hygiene leads to drop in confidence in treatment
  • Cultural beliefs
  • Cost
103
Q

What is a Trachoma and how is it treated ?

A

A bacterial infection due to face washing with dirty water (chlamydia trachmatis). Malnutrition in Vit A disposes people. Antibiotics and surgery needed.

104
Q

What is Onchocerciasis/river blindness ?

A

Transmitted by blackfly, it causes eye lesions, inflammation and scarring. Annual dose of Ivermectine needed.

105
Q

What is childhood blindness ?

A

Vit A deficiency causes corneal scars.

106
Q

What can be done to prevent illness in MIC/LIC’s ?

A
  • Education
  • Better sanitation
  • Better medical facilities
  • Vaccinations
  • Target nutrition
107
Q

What loss is classed as disabling hearing loss in adults?

A

Loss of more than 40 dB