Eyes Flashcards
(107 cards)
1
Q
What makes the Cornea transparent ?
A
Regularly arranged collagen fibres
No blood vessels
AH pumped out via endothelial layer pumps
2
Q
What is the first layer of the retina (outside) ?
A
Pigmented layer
3
Q
What is the second layer of the retina (outside) and what is found there ?
A
Neural layer - rods and cones
4
Q
What supplies the retina with blood ?
A
From the outside via the choroid and from the inside via the central retinal artery
5
Q
What is lens opacification called ?
A
Cataracts
6
Q
What predisposes the lens to becoming opacified ?
A
Avascular and exposure to UV rays
7
Q
What can be used to visualise tear film ?
A
Fluroscein
8
Q
Function of aqueous humor ?
A
Maintain IOP
9
Q
Function of vitreous humor ?
A
Cushion and support the retina
10
Q
What structures form from the side of the forebrain to make the eyes ?
A
Optic vesicles
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
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.
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.
14
Q
What happens when the choroidal fissure closes ?
A
The vessels are enclosed in the optic stalk, they form the central retinal artery.
15
Q
Corneal dystrophies
A
- Central vision is lost
- Run in families
- Material builds up in the cornea
- Bilateral
16
Q
How do we treat corneal dystrophies ?
A
- Corneal transplants
- Laser treatment (PTK)
17
Q
Corneal degenerations
A
- Peripheral vision lost
- Unilateral
- Usually seen with systemic diseases
18
Q
Retinal detachment - what happens ?
A
VH goes between the pigmented layer and the neural layer causing detachment.
19
Q
Retinal detachment symptoms
A
- Flashing lights
- Floaters
- Vision loss/dark curtain
20
Q
Coloboma
A
Hole in one of the structures of the eye. Affects vision differently depending on location
21
Q
Glaucoma - What causes it ?
A
Raised IOP
22
Q
Two types of Glaucoma
A
Primary Open Angle Glaucoma
Closed Angle Glaucoma
23
Q
Symptoms of Primary Open Angle Glaucoma
A
- Asymptomatic
- Peripheral vision is usually affected first.
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
25
Symptoms of Cataracts
- Blurred vision
- Difficulty seeing in dark
- Sensitivity to bright lights
- Fading of colours
26
What is the blood-occular barrier created by ?
Barrier between the endothelium of the capillaries in the iris, retina and ciliary body and the retinal pigment epithelium.
27
why is the blood ocular barrier important ?
Prevents substances from passing through into the eye from blood vessels.
28
What are the two parts of the barrier ?
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
29
Retinal detachment - How is it treated ?
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.
30
Hordeolum/Stye
Infection of the mebomian (internal) or sebaceous glands (external) of the eyelid.
31
Definition of refractive error
Problem focusing light accurately onto the retina due to the shape of the eye.
32
What is Retinitis Pigmentosa ?
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.
33
What is Optic Neuritis ?
Inflammation of the optic nerve. Pain and temporary vision loss are common symptoms.
34
Electroretinography (ERG)
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.
35
Gene therapy - What and when ?
Used to replace missing or defected genes in the eye in order to correct genetic disorders. Used in Wet AMD and diabetic retinopathy currently.
36
Why do muscles of the eye have more than one function ?
They are attached in the orbital axis where as the eye is in the optical axis.
37
Definition of Phototransduction
Phototransduction is the process by which the absorbed light triggers an electrical response in rods and cones.
38
What are the steps of Phototransduction ?
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.
39
What role does vitamin A play in the visual pigment ?
Visual pigment regeneration
40
What happens if you are deficient in Vit A ?
- Night-blindness
| - Unhealthy conjunctiva and corneal epithelium
41
What are the first signs of Vit A deficiency ?
Bitot's spots and Corneal Ulceration. Corneal melting occurs later on if deficiency isn't rectified.
42
What causes colour blindness ?
Some cone cells are deficient or abscent and this means some people are unable to distinguish certain colours.
43
What part of the NS causes pupil constriction ?
Parasympathetic - Sphincter pupillae
44
What part of the NS causes pupil dilation ?
Sympathetic - Dilator pupillae
45
Definition of refraction
The bending of light as it passes through one medium to another
46
What causes refraction in the eye ?
The cornea and lens mainly but also the AH and VH.
47
What structure has the most powerful bending ability ?
The cornea (45D) compared to the lens (15D). The lens is able however to change its bending power.
48
Which fibres cross at the optic chiasma ?
The nasal fibres that see the temporal fields.
49
What is the MFL ?
Medial longitudinal fasciculus
50
What does the MFL contain ?
- 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
Where to the fibres of the pupillary reflex go to ?
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
How do the parasympathetic fibres enter the orbit ?
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
Is this response unilateral or bilateral ?
Unilateral
54
What signs can be seen in the eye if the sympathetic chain is damaged ?
Anhydrosis
Ptosis
Miosis
55
What is the conjunctiva ?
A thin vascular membrane that covers the surface of the eyelids and sclera. It doesn't cover the cornea.
56
What is conjunctivitis ?
Infection of the conjunctiva. Can be viral or bacterial.
57
What are the symptoms of conjunctivitis ?
- Red eye
- Watery
- Discharge
58
How do you treat conjunctivitis ?
- Antibiotic eye drops
| - Good eye hygiene
59
What do you call a corneal transplant ?
Keratinoplasty
60
What lens in implanted to cure cataracts ?
Posterior Chamber Intraoccular Lens (PCIOL)
61
Symptoms of Glaucoma
- Raised IOP
- Pale, unhealthy optic disk
- Visual disturbances
62
What is the topical management of PA Glaucoma ?
- Beta blockers
- Prostaglandin analogues
- Carbonic anhydrase inhibitors
63
What other techniques may be used if topical treatments for Glaucoma fail ?
- Laser trapectuloplasty
| - Trabeculectomy surgery
64
Acute management for CA Glaucoma ?
- IV carbonic anhydrase inhibitor
- Pilocarpine
- Analgesics
- Anti-emetics
65
What surgery is performed to treat CA Glaucoma ?
Laser Iridotomy
66
What part of the eye does anterior uveitis affect ?
Iris +/- Ciliary body
67
What part of the eye does intermediate uveitis affect ?
Ciliary body
68
What part of the eye does posterior uveitis affect ?
Choroid
69
How would patient present with Uveitis ?
- Red eye
- Painful to move
- Hazy vision/floaters
- Vision may be lost
- Photophobia
70
What is Optical Coherence Tomography used for ?
OCT is used to look at the layers of the retina
71
What 3 conditions can result in sudden vision loss ?
1. Central retinal vein occlusion
2. Central retinal artery occlusion
3. Optic Neuritis
72
How do you treat a central retinal artery occlusion ?
Identify and treat risk factors
- Reduce cholesterol
- Reduce BP if high
- Other medical conditions need to be under control
73
How do you treat a central retinal vein occlusion ?
- 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
How does Optic Neuritis caused by Giant Cell Arteritis present (4) ?
- Jaw claudication
- Scalp tenderness
- Vision loss
- Headaches
75
How do you treat Giant Cell Arteritis ?
High dose prednisolone
76
How do you treat Non-Arteritic Optic Neuritis ?
Identify and treat risk factors.
- Reduce cholesterol
- Reduce BP if high
- Other medical conditions need to be under control
77
What is age related macular degeneration ?
Lose central vision and a distorted image develops
78
What can be seen changing in the eye ?
- The pigment epithelial
| - Drunsen appears
79
What are the two types of AMD ?
Wet and Dry
80
What occurs in Dry AMD
- Drunsen
| - Atrophy
81
How do you manage Dry AMD ?
- Low vision aids
| - Registration
82
What occurs in Wet AMD ?
- New choroidal vessels
83
What Investigations should be done to confirm Wet AMD ?
Fluroscein angiography and OCT
84
How do you treat Wet AMD ?
- Intravitreal anti VegF
- Low vision aids
- Registration
85
What happens to the eye in Diabetic Retinopathy
- Haemorrhages
- Exudates
- Neovasculation
- Microaneurysms
86
What investigation should be done to confirm Diabetic Retinopathy ?
Fluroscein angiography and OCT
87
How do you treat Diabetic Retinopathy ?
- Intravitreal anti VegF
- Low vision aids
- Registration
- If young you would start giving anti VegF, carry out Laser-Panretinal Photocoagulation
88
What systemic conditions may cause retinal degenerations ?
- Lupus
- Diabetes
- Rhematoid Arthritis
89
How do patients present with allergic conjunctivitis ?
- Sore red eye
- Itching
- Watery eyes
- Swelling
90
How do you treat patients with allergic conjunctivitis ?
- Topical antihistamines
- Avoid the antigen
- Mast cell stabilisers
91
What will a patient present like who has a corneal abrasion ?
- Painful
- Watery eye
- Blurred vision
- Red eye
92
How do you treat patient with a corneal abrasion ?
- Analgeics
| - Topical antibiotics
93
How do you treat a patient with Anterior Uveitis ?
- Oral Corticosteroids
| - Mydriatic eye drops
94
What is a Hypopyon ?
It's a condition involving inflammatory cells in the anterior chamber of the eye. Exudative.
95
How do you treat a Hypopyon ?
- Oral Corticosteroids
| - Mydriatic eye drops
96
How do patients present with Scleritis ?
- Red eye
- Watery
- Painful
97
How do you treat Scleritis ?
Give stystemic steroids
98
What is Orbital Cellulitis ?
Infection/inflammation of the tissues surrounding the eye.
99
How does a patient present with Orbital Cellulitis ?
Patient will present with symptoms of infection e.g. fever, malaise. They may have a sore, red eye and complain of double vision.
100
How do you treat a patient with Orbital Cellulitis ?
- IV antibiotics
- CT scan
- Drainage of pus
101
Which two eye conditions result in the most people globally being visually impaired ?
Cataracts and refractive error
102
What factors stop people seeking medical help ?
- Hard to access
- Poor hygiene leads to drop in confidence in treatment
- Cultural beliefs
- Cost
103
What is a Trachoma and how is it treated ?
A bacterial infection due to face washing with dirty water (chlamydia trachmatis). Malnutrition in Vit A disposes people. Antibiotics and surgery needed.
104
What is Onchocerciasis/river blindness ?
Transmitted by blackfly, it causes eye lesions, inflammation and scarring. Annual dose of Ivermectine needed.
105
What is childhood blindness ?
Vit A deficiency causes corneal scars.
106
What can be done to prevent illness in MIC/LIC's ?
- Education
- Better sanitation
- Better medical facilities
- Vaccinations
- Target nutrition
107
What loss is classed as disabling hearing loss in adults?
Loss of more than 40 dB
