Opthalmology Flashcards
(239 cards)
1
Q
What is cerebrospinal fluid produced by?
A
Secretory epithelium of the choroid plexus
* formed in the ventricles and then circulates in the subarachnoid space and absorbed into venous circulation
2
Q
Function of CSF? (3)
A
- mechanical protection: protects brain tissue
- homeostatic function: pH of CSF affects pulmonary ventilation and cerebral blood flow
- circulation: exchange of nutrients and removal of waste
3
Q
Which cells secrete CSF?
A
choroidal cells
4
Q
Describe structure of choroid plexus?
A
Lots of finger-like projections , lined by ependymal cells
5
Q
What is the choroid plexus?
A
networks of capillaries in the walls of ventricles
6
Q
How is CSF produced by choroidal cells?
A
- Basolateral surface absorbs H2O, Na, HCO3 + Cl
* Secreted by apical surface
7
Q
What is the secretion of CSF by choroid plexus dependent on?
A
Active Na+ transport, which pulls Cl-, and both ions drag water by osmosis
8
Q
Difference in composition between CSF and blood plasma?
A
- CSF = higher concentrations of Na and Cl
* Lower concentrations of K+, glucose and protein
9
Q
Explain how the ventricles of the brain are connected (4)
A
- Intraventricular Foramina (of Monroe): Lateral Ventricles to Third Ventricle
- Cerebral Aqueduct (of Sylvius): Third Ventricle to Fourth
- Foramen of Magendie: Median aperture – Fourth ventricle to subarachnoid space
- Foramina of Luschka: Lateral apertures – Fourth ventricle to subarachnoid space
10
Q
Explain CSF circulation
A
- CSF added by choroid plexus in roof of 3rd ventricle
- Then flows through cerebral aqueduct to 4th ventricle
- Another choroid plexus in 4th ventricle adds more CSF
- CSF then enters subarachnoid space through median aperture + 2 lateral apertures
- Enters spinal cord
11
Q
How is CSF returned to venous blood?
A
through arachnoid granulations into the superior sagittal sinus (SSS)
12
Q
Pathologies of ventricles, choroid plexus and CSF? (4)
A
- Tumours - colloid cyst, ependymomas
- Ventricular haemorrhage - epidural haematoma (between skull and dura), subdural haematoma (between dura and arachnoid)
- hydrocephalus
- idiopathic intracranial hypertension
13
Q
Papilloedema?
s/s? (3)
A
Optic disc swelling due to increased intracranial pressure
- enlarged blind spot
- blurring of vision
- Vision loss
14
Q
Aqueous humor?
Function? (2)
A
Specialised fluid that bathes structures within the eye
- provides oxygen and metabolites
- contains bicarbonate to buffer H+ produced in cornea
15
Q
Where is aqueous humor produced?
A
Produced by epithelium of ciliary body into anterior chamber of eye
16
Q
Describe structure of ciliary body
A
2 layers of epithelial cells
- pigment epithelium of retina
- nonpigmented epithelial layer (NPE) - it is NPE layer that generates aqueous humor
17
Q
Describe production of aqueous humor (5)
Which drugs inhibit this pathway?
A
- HCO3 and H+ are formed in epithelial cells from hydration of CO2 by carbonic anhydrase
- Transported out of cell in exchange for influx of Cl and Na
- Cl and Na pass from PE into NPE through gap junctions
- Transported out of NPE into aqueous humor by Na/K/Cl co-transporter
- Water follows through aquaporins
CA inhibitors block pathway decreasin production of aqueous humor
18
Q
Examples of carbonic anhydrase inhibitors (2)
What are they used to treat?
Mechanism?
A
Dorzolamide + acetazolomide
* Glaucoma - raised intra-ocular pressure caused by too much aqueous humor
Mechanism: reduces production of aqueous humor
19
Q
Innate immune system of the eye? (3)
A
Blink reflex
* Tears (physical) - flushing, mucous layer
Chemical
* Tears (chemical) - lysozyme, (gram -ve bacteria + fungi), lactoferrin and transferrin (gram ve+), lipids, secretory IgA, antimicrobials (IL-6)
Cellular
* Tears (cellular) - neutrophils, macrophages, conjunctival mast cells
20
Q
What is the principle APC for external eye?
Where are they found?
A
Langerhans cells
* found at corneo-scleral limbus + peripheral cornea (absent from central 1/3rd cornea)
21
Q
What is the only part of the eye with lymphatic drainage?
Features of conjunctival immunity (5)
A
Conjunctiva
- lymphocytes
- dendritic cells
- MALT
- macrophages, langerhans cells and mast cells
- commensal bacteria
22
Q
Features of cornea and sclera immunity? (5)
A
- Avascularity
- No lymphoid tissue
- Lack of APCs
- Langerhans cells only in peripheral cornea
- downregulated immune environment
23
Q
Lacrimal gland immunity (2)
A
- More IgA and CD8 T cells compared to conjunctiva
* Lacrimal drainage system - lymphoid tissue
24
Q
What make up the blood-ocular barrier? (2)
Immunity? (2)
A
Retina and choroid
- lack of APCs
- downregulated immune environment
25
In which areas of the eye is immune system downregulated?(5)
* Vitreous
* Choroid
* Retina
* cornea
* sclera
26
What sites of the eye are immune privileged? (5)
What is meant by immune privilege?
* Cornea
* anterior chamber
* lens
* vitreous
* subretinal space
These sites can tolerate foreign pathogens without generating immune response
27
Mechanisms of ocular immune privilege? (4)
* blood-ocular barrier
* lack of lymphatic drainage/lymphoid tissue
* immunosuppressive molecules
* anterior chamber-associated immune deviation (ACAID)
28
What does ACAID result in?
| Function?
Peripheral tolerance to ocular antigens
| * protects eye from potentially damaging immune response
29
Immunological ignorance?
Corneal cells have decreased expression MHC class I molecules and do not express MHC class II
30
Sympathetic opthalmia?
What is injured eye known as?
Other eye?
Can you tell the difference between the eyes?
rare, BILATERAL, granulomatous uveitis due to trauma or surgery to ONE eye
* injured eye = exciting eye
* other = sympathising eye
Clinically both eyes appear the same and it is only by history that one can identify which eye is the exciting eye
31
Type I hypersensitivity disease of the eye?
Type 2?
3?
4?
Type 1 = acute allergic conjunctivitis
Type 2 = occular cicatrical pemphigoid (blistering disease)
Type 3 = autoimmune corneal melting
type 4 = corneal graft rejection
32
Side effects of steroids on the eye? (2)
* Cataracts
| * Steroid-induced glaucoma
33
pathway for signal transmission in the eye?
| What lateral connections influence signal processing? (2)
Photorecpetors (innermost part) -> bipolar cells -> ganglion cells
* Horizontal cells - receive input from photoreceptors and project to other photoreceptors and bipolar cells
* Amacrine cells - receive input from bipolar cells and project to ganglion cells, bipolar cells and other amacrine cells
34
Function of photoreceptors?
Structure? (4)
Types of photoreceptors? (2)
Converts electromagnetic radiation to neural signals (transduction)
4 main regions
* outer segment
* inner
* cell body
* synaptic terminal
Types
* rods and cones
35
Explain phototransduction (2)
* Photoreceptors have depolarised Vm (compared to other neurons, resting Vm is more positive ~ -20mV)
* with light exposure, Vm HYPERPOLARISES (unlike most neurones)
36
What causes positive Vm of photoreceptors?
* positive Vm is because of the “dark current”. A cGMP-gated Na+ channel that is open in the dark and closes in the light
* change in Na+ with light is the signal that enables the brain to perceive objects in the visual field
i.e. light causes less glutamate (neurotransmitter) secretion
37
Explain the "dark current"
In the dark
* Pna = Pk
In response to light
* Pna is reduced (Pk > Pna)
* therefore hyperpolarises
* change is LOCAL and GRADED
38
In which conditions is more glutamate released in the eye?
In dark, more glutamate (neurotransmitter) released than in light
39
What is the visual pigment molecule in rods?
Rhodopsin
| * Retinal (vit A derivative) + opsin (GPCR)
40
Molecular basis of phototransduction?
* Light converts 11-cis-retinal to all-trans-retinal (activated form)
* all-trans-retinal activates transducin
* decreases cGMP
* leads to closure of cGMP-gated Na+ channel
* lowered Na results in hyperpolarisation
41
What is visual acuity?
Ability to distinguish between 2 nearby points
42
What are rods used for?
Cones?
Are rods high convergence or low convergence?
```
Rods = seeing in dim light
Cones = seeing in normal daylight
```
* More convergence in rod system, increasing sensitivity + decreasing acuity
43
Differences between rods and cones? (5)
Rods
* achromatic
* peripheral retina
* high convergence
* high light sensitivity
* low acuity
Cones
* chromatic
* central retina (fovea)
* low convergence
* low light sensitivity
* high acuity
44
Differences between rods and cones? (5)
Rods
* achromatic
* peripheral retina
* high convergence
* high light sensitivity
* low acuity
Cones
* chromatic
* central retina (fovea)
* low convergence
* low light sensitivity
* high acuity
45
Explain the visual field of the eye
* Each eye sees a part of the visual space - monocular visual field
* but their
visual fields overlap to create a binocular visual field
* retina is divided in half, relative to the fovea, into a nasal and
a temporal hemiretina
46
Explain nerve fibres from nasal and temporal sides of retina
* Nasal half (60%) = cross over at optic chiasm
| * Temporal (40%) do not
47
Where is information from right visual field processed?
| Superior visual field?
* Right = left cortext
| * Superior = lower cortext
48
Amblyopia?
Ax?
Tx?
Cortical blindness - visual disorder when there is no problem with the eye i.e. one eye has better vision than the other
* Ax = strabismus (wandering eye)
* Tx = surgery
49
Hydrocephalus?
| Sign?
Increased CSF in cranium
| * white showing above and below iris
50
What are meninges?
| Where is CSF found?
```
3 layers surrounding brain
(from superficial to deep)
* Dura mater
* arachnoid mater
* pia mater (thinnest)
```
CSF found deep to arachnoid mater
51
What is found between the 2 layers of the dura mater?
Venous sinus
52
What happens when there is increased pressure via fluid in the brain?
Brain will be pushed through tentorial notch, causing pressure on brainstem
53
What is the first sign of ICP>
The eyes
54
Where are the third and fourth ventricles found?
* Third ventricle = between thalami
| * Fourth = between pons and cerebellum
55
Eye s/s with ICP? (5)
* blurred vision
* double vision (diplopia)
* loss of vision
* papilloedema (swelling of optic disc due to raised ICP)
* pupillary changes
56
Why is optic nerve considered an extension of the brain?
It has meninges
* dura
* arachnoid
* pia
57
What is the space between arachnoid and eyeball called?
Subarachnoid space
58
Complications of raised ICP? (3)
* Compress optic nerve
* compress central artery and vein of retina
* papilloedema
59
Occulomotor nerve function? (2)
| S/s of CN III damage? (4)
* Supplies somatic motor to extrinsic muscles of eye
* constricts pupil via parasympathetics
S/s
* no pupillary light reflex
* dilated pupil
* ptosis
* eye looking down + out
60
Complications of damage to trochlear nerve? (3)
* Paralysis to superior oblique muscle
* inferior oblique is unopposed to eye cannot move inferomedially!!
* Diplopia when looking down
61
Complications of damage to abducent nerve? (2)
* Paralysis of lateral rectus muscle
| * medial deviation of eye
62
What does cavernous sinus contain?
* oculomotor nerve
* trochlear nerve
* trigeminal nerve
* abducens nerve
63
Ax of neuro-opthalmic disease (movement + visual defects)? (6)
* Vascular disease
* Tumours (primary and secondary) - SOLs
* Trauma
* Demyelination
* Inflammation/infection
* Congenital abnormalities
64
Ix cause of neuro-opthalmic disease? (2)
* Blood tests
| * Imaging (MRI - gold standard)
65
Ocular motility defects? (5)
* IIIrd Nerve
* IVth Nerve
* VIth Nerve
* Inter-nuclear
* Supra-nuclear (initiation of movement of eye is broken)
66
Ax VIth nerve palsy?
| S/s?
* Microvascular
* Raised Intracranial pressure (papilloedema)
* Tumour
* Congenital
Lateral rectus - no abduction
67
IVth nerve?
| S/s palsy? (4)
Superior oblique
* Intorsion (depression in adduction)
* Patients often compensate with head tilt
* Sclera visible below iris (eye elevated)
* problems with eye depression
* patients will have double vision
68
Why is 6th CN prone to be affected by raised ICP?
* close to petrous tip
69
Ax IVth nerve palsy?
Congenital decompensated
Microvascular
Tumour
Bilateral – closed head trauma
70
CN III nerve function?
```
Medial rectus muscle
Inferior rectus
Superior rectusInferior oblique
Sphincter pupillae (efferent - remember afferent is optic nerve)
Levator palpebrae superioris
```
71
IIIrd nerve palsy s/s? (2)
| Ax?
Eye down and out
Ptosis
* Microvascular
* Tumour
* Aneurysm!!! (particularly susceptible)
* MS
* Congenital
72
Painful third nerve palsy?
ANEURYSM
73
Function of inter-nuclear pathways?
Helps eyes work together
LOOK LEFT!
Left eye looks left
Right eye looks left
At the same time and same speed
74
Inter-nuclear opthalmoplegia?
| Ax inter-nuclear opthalmoplegia? (2)
If left inter-nuclear opthalmoplegia, can still move right eye left, but left eye cannot (eye can't catch up so will see nystagmus!)
* Multiple sclerosis
* Vascular (stroke)
75
Visual field defects? (5)
Ax? (4)
```
optic nerve
chiasm
optic tracts (1-sided field)
optic radiations (split into quadrants)
cortex
```
Ax
* Vascular disease - CVA
* Space occupying lesion (SOL)
* Demyelination (MS)
* Trauma - including surgical
76
Plaques on MRI?
MS - demyelinating disease (cause of inter-nuclear opthalmoplegia)
77
Optic nerve pathology? (3)
```
Ischaemic Optic Neuropathy
Optic neuritis – commonly MS
Tumours - rare
* Meningioma
* Glioma
* Haemangioma
```
78
How does optic nerve pathology affect visual field?
Either complete or horizontal
79
Optic neuritis s/s? (4)
| Tx?
* Progressive visual loss (unilateral)
* Pain behind eye, especially on movement
* Colour desaturation
* Central scotoma (missing central/macular vision)
Tx
Gradual recovery over weeks - months
80
Complication of optic neuritis?
Optic atrophy
(optic nerve appears incredibly pale)
- marked RAPD
81
Optic chiasm pathology?
| Tx?
Pituitary tumour
Craniopharyngioma
Meningioma
* Tx pituitary tumours = Visual loss or disturbance is commonly reversed after the tumour is decompressed or removed
82
Visual defect of optic chiasm pathology?
Bi-temporal field defect
83
Optic tracts and radiations pathology? (3)
| S/s? (4)
Tumours (primary or secondary)
Demyelination
Vascular anomalies
S/s
* Homonomous defects
* Macula not spared
* Quadrantanopia
* Incongruous (not symmetrical)
(remember, once past, defects are only on one side. If only in quadrants, have not reached lateral geniculate)
84
Occipital cortext pathology Ax? (2)
| S/s? (3)
```
Vascular disease (CVA)
Demyelination
```
S/s
* Homonomous defect
* Macular sparing
* Congruous
85
Hyphaema?
Blood in anterior chamber of eye (intra-oculr injury i.e. rupture of iris)
86
What are the signs of corneal laceration?
if break in cornea, iris will plug wound meaning pupil will be mishapen
87
Sidel test?
Flouroscien in full penetrating injury
88
When is penetrating foreign body suspected? (4)
* pupil irregular
* anterior chamber shallow
* localised cataract
* gross inflammation
89
what should you do if you suspect intra-ocular foreign body?
ALWAYS X-RAY!!!!
90
Difference between acid and alkali burns eye?
* Akali - easy, rapid penetration
| * Acid - little penetration
91
What is it important to look for in alkali burns?
Ischaemia (especially limbal ischaemia where stem cells are i.e. cornea may never heal)
92
Tx of chemical injury? (2)
* IRRIGATE!! (2l saline)
| * Asses at slit lamp
93
What is the lens lined with?
| What is the main pathology of the lens?
Epithelium
| * main pathology = cataracts
94
What are cataracts?
| Ax? (6)
Opacifications within lens
Ax
* age-related (degenerative)
* UVB damage
* hypertension
* smoking
* post-op
* DIABETES!!!!!
95
Glaucoma?
| Ax?
Increase in pressure in the eye
* aqueous humor normally drains through trabecular meshwork + canal of schlemm
* glaucoma occurs when there is a blockage in drainage thru canal
96
Types of glaucoma?
* Open angle = most common (poor drainage thru trabecular network)
* closed angle = drainage thru network is patent but iris is opposed to anterior eye and fluid can't get past
97
Open vs closed glaucoma?
Open
* slow onset, often asymptomatic
* tx = pharmacological
Closed
* emergency! can lose sight quickly
* laser surgery
98
Opthalmoscopy sign of glaucoma?
Cupping = raised intra-ocular pressure damaged optic disc and nerve (increased size of cup)
99
What is papilloedema?
swelling of optic nerve/disc due to raised ICP
100
Difference between scleritis and episcleritis?
Scleritis
* more severe
* associated with pain on movement
* underlying autoimmune disease e.g. SLE
Episcleritis
* superficial and self-limiting
101
ARMD?
| Types? (2)
Age-related macular degeneration
* Dry = no significant vascular proliferation
* wet = vascular proliferation (wet due to haemorrhage) - associated with far more visual loss!!
102
What accumulates in ARMD?
Drusen - proteins, lipids and inflammatory mediators
| * look like yello wplques, similiar to atheroma
103
What leads to wet ARMD?
| Tx?
VEGF - new vessels are leaky
| Tx = monoclonal antibodies ot VEGF
104
Diabetic eye conditions? (6)
* blurred vision
* Argyll Robertson pupil -often called prostitute's pupil because it accomodates (near and far) but doesn't react (pupil dilation)
* Cataracts
* Glaucoma - in diabetes, called rubeotic glaucoma
* Diabetic retinopathy - leaky vessels and small aneurysms form
105
Vascular diseases of the eye? (4)
Arterial occlusion and venous occlusion
* Central retinal artery occlusion (CRAO)
* Central retinal vein occlusion (CRVO)
* Arterial thromboembolism in eye - curtain
* Vasculitis can affect vessels of the eye – Giant cell!!
106
Malignancy of the eye? (3)
Same as skin
* BCC
* SCC
* Melanoma (retinal melanoma = melanocytes at back of eye)
107
Which drugs are good for penetrating cornea?
LMW drugs - cornea is a lipid-water-lipid sandwich (epithelium is lipophillic, stroma is hydrophillic)
Therefore, lipid soluble drugs penetrate epithelium and water soluble drugs penetrate stroma
108
Example of a drug that has both lipophillic and hydrophillic properties? Advantage?
Chloramphenicol - can penetrate cornea easily
109
What are hydrophillic drugs limited by?
| Hydrophobic drugs?
* Hydrophillic drugs limited by epithelium
| * Hydrophobic drugs limited by stroma
110
what is added to topical steroids to make them more hydrophobic?
Hydrophillic?
Examples? (2)
* Hydrophobic = alcohol or acetate
* Hydrphillic = phosphate
Prednisolone acetate
Prednisolone phosphate
111
Properties of prednisolone acetate? (3)
| Prednisolone phosphate? (3)
Prednisolone acetate
* hydrophobic
* good penetration in uninflamed cornea
* used post-operatively
Prednisolone phosphate
* hydrophilic
* Poor penetration in uninflamed cornea (inflammation can reduce hydrophobic nature of cornea)
* Used for cornea disease or when want low dose steroids
112
What is benzylkonium? Used for?
A preservative that disrupts lipid layer of tear film
| * aids penetration of some drugs
113
what is bimatoprost?
Drug used to lower IOP in glaucoma (benzylkonium aids penetration)
114
How can you prevent systemic absorption of topic eye drugs?
tears pumped out of lacrimal sac rapidly = limited by punctal occlusion
115
Types of ocular injection? (2)
* Intravitreal
| * Intracameral
116
What are examples of eye drops used to treat infections? (2)
* Chloramphenicol
| * Zovirax
117
Anti-inflammatory agents for the eye? (4)
Steroids
Topical NSAIDs
Anti-histamines
Mast cell stabilisers
118
When are steroids used topically on the eyes?
* post op cataracts
* uveitis
* to prevent corneal graft rejection
119
Local side effects of steroid drops? (3)
| Systemic? (6)
Local
* cataract
* glaucoma
* exacerbation of viral infection
Systemic
* Gastric ulceration
* Immunosuppression
* Osteoporosis
* Weight gain
* Diabetes
* Neuropsychiatric effects
120
Examples of topical steroids? (3)
* Predsol (prednisolone phosphate)
* Betamathasone
* Dexamethasone/ prednisolone acetate
121
What are antihistamines and mast cell stabilisers used in?
| NSAIDs?
* Antihist and MCS = hayfever or allergic conjunctivitis
| * NSAIDs use din pain relief
122
Glaucoma medication? (5)
* Prostanoids e.g. latanoprast (Xalatan)
* B-blockers
* CA inhibitors e.g. dorzolamide
* Alpha agonists e.g. brimonidine
* Parasympathomometic - pilocarpine
123
What drugs are administered through intravitreal methods? (3)
* Antibiotics in endophthalmitis
* intra-ocular steroids
* anti-vegf
124
Endophthalmitis?
Inflammation of interior eye (normally post-surgery)
SIGHT-THREATENING!!
125
How do local anaesthetics of the eye work?
| Used for? (5)
Block sodium channels and impede nerve conduction
* foreign body removal
* tonometry (IOP measurement)
* corneal scraping
* comfort
* cataract surgery
126
Most common diagnostic dye for eyes?
| Uses? (6)
Fluorescein
* shows corneal abrasion
* dendritic ulcer
* leaks
* tonometry
* nasolacrimal duct obstruction
* angiography
127
Mydriatics?
Examples?
Side effects? (2)
Drugs that cause pupil dilation by blocking parasympathetic supply to iris
* e.g. tropicamide, cyclopentolate
Side effects
* blurring
* angle-closure glaucoma
128
Signs of acute angle closure glaucoma? (2)
* Headache
| * Vomiting
129
Sympathomimetics?
Cycloplegia?
Do all sympathomimetics cause cycloplegia?
Act of sympathetic system and cause pupil to dilate
Cycloplegia = paralysis of ciliary muscle
* some cause = atropine
* some don't = phenylephrine
130
why do antibiotics given systemically not enter the eye?
Inner and oter retinal blood barrier
131
Goldren rule with herpetic keratitis?
NEVER give steroids
132
ethambutol associated with?
chloroquine?
Amiodarone?
* optic neuropathy
* maculopathy
* vortex kerotopathy
133
Types of eye infection? (4)
* Conjunctivitis
* cornea = keratitis
* entire globe = endophthalmitis
* cellulitis
134
Bacterial conjunctivits in neonates caused by?
| What about all other ages? (3)
* staph aureus
* neisseria gonorrhoeae
* chlamydia trachomatis
Other ages
* staph aureus
* strep pneumoniae
* haemophilus influenzae
135
Tx bacterial conjunctivitis?
Chloramphenical
| * DO NOT use if history of aplastic anaemia or allergy!!
136
Ax viral conjunctivitis? (3)
* Adenovirus
* Herpes simplex
* herpes zoster
137
Chlamydial conjunctivitis?
Chronic history - unresponsive to tx (may or may not have symptoms of urethritis, vaginitis)
138
Ax microbial keratitis? (3)
* Bacteria
* Viruses - herpes, adenovirus
* Fungi
139
Tx bacterial keratitis? (2)
* Admission for hourly drops
| * daily review
140
Pathogenesis of diabetic retinopathy?
* Chronic hyperglycaemia leads to glycosylation of protein/basement membrane
* loss of pericytes leading to microaneurysms
* Microaneurysms can either cause leakages or ischaemia
141
Signs of non-proliferative retinopathy?
```
microaneurysms / dot + blot haemorrhages
hard exudate
cotton wool patches
abnormalities of venous calibre
Intra-retinal microvascular abnormailities (IRMA)
```
142
Where do new vessels grow?
grow on disc (NVD)
grow in the periphery (NVE)
grow on iris if ischaemia is severe
143
Difference between NVE and NVD?
NVE
* Periphery
* ischaemia is local
* better prognosis
NVD
* optic disc
* ischaemia is widespread
* worse prognosis
144
What is rubeosis iridis?
Progressive ischaemia = iris affected (sight restoration is impossible)
145
what do diabetic patients lose vision due to? (3)
* retinal oedema affecting fovea
* vitreous haemorrhage
* scarring
146
Classification of retinopathy?
* No retinopathy
* mild
* moderate
* severe
* proliferative retinopathy
147
Management of diabetic retinopathy/maculopathy? (2)
Laser
* PRP (essentially cooking and killing bits of retina)
Surgery - virectomy (only way to get rid of scarring)
148
disadvantage of laser therapy for diabetic retinopathy?
sacrifice peripheral sight for central
149
Tx disc neurovascularisation? (2)
* Laser
| * Intra-ocular anti-VEGF
150
Features of hypertensive retinopathy? (4)
* cotton wool spots (associated with hypertension more than diabetic retinopathy)
* hard exudates
* retinal haemorrhage
* optic disc oedema
151
S/s central retinal artery occlusion? (3)
* Sudden painless loss of vision
* very profound loss of vision
* retinal nerve fibre layer becomes swollen except at fovea (cherry red spot)
152
CRVO s/s? (2)
* sudden painless visual loss
| * range of visual loss
153
branch vein occlusion? (2)
* painless disturbance in vision
| * may be asymptomatic
154
Features of thyroid eye disease?
Extraocular
* proptosis
* lid retratcion, oedema, lag
* restricitve myopathy = diplopia
Intra-ocular
Anterior segment
* chemosis
* glaucoma
Posterior segment
* choroidal folds
* optic nerve swelling
155
what is thyroid eye disease characterised by?
| Tx? (3)
swelling of the extraocular muscles and orbital fat
Tx
* control thyroid levels
* lubricants
* surgical decompression (for glaucoma and that)
156
How does RA affect eyes? (3)
* Dry eyes (keratoconjunctivitis sicca)
* scleritis
* corneal melt
157
Sjogren's syndrome triad?
* keratoconjunctivitis sicca
* xerostomia (dry mouth)
* rheumatoid arthritis
158
Stevens-Johnson syndrome affects eye? (3)
* symblepharon (adhesions of palpebral conjunctiva of eyelid to bulbar conjunctiva of eyeball)
* occlusion of lacrimal glands
* corneal ulcers
159
Herpetic keratitis?
* very painful
| * recurrent
160
why should you NEVER treat kerpetic keratitis with steroids??
can cause corneal melt and perforation of cornea!!
161
Adenoviral keratitis features? (4)
* bilateral
* follows URTI
* contagious
* may affect vision
162
Tx adenoviral keratitis?
* topical AB
| * steroids to speed up recovery if becomes chronic
163
What fungi are associated with keratitis caused by contact lenses?
Acanthamoeba
| pseudomonas aeruginosa
164
Fungal keratitis features? (2)
* Takes long time to heal
| * contact lesnes
165
Features of orbital cellulitis? (5)
* painful - especially on eye movement
* proptosis
* associated with sinusitis
* pyrexial
* sight-threatening
166
Organisms involved in orbital cellulitis? (4)
* staphylococci
* streptococci
* coliforms
* haemophilus influenzae!
167
Tx orbital cellulitis? (2)
* broad spectrum AB
| * drain abscesses
168
Endophthalmitis?
| S/s? (3)
Devastating infection inside of the eye
* extremely painful!!
* very red eye
* sight threatening
169
Organisms involved in endophthalmitis?
* often conjunctival commensals
| * most common is staph epidermidis
170
Tx endophthalmitis?
Intravitreal
* amikacin
* ceftazidime
* vancomycin
171
Ax chorioretinitis? (3)
* CMV in AIDS
* toxoplasma gondii
* toxocara canis (worm)
172
toxoplasmosis?
Ax?
S/s?
```
protozoan infection (toxoplasmosis gondii)
* Ax = cats + raw meat
```
* Mild flu like symptoms
* in immunocompetent patient = cyst formation (pathogen is latent, can reactivate)
173
Tx toxoplasmosis?
If reactivates, can be sight-threatening
| So reqs systemic tx
174
Toxocara?
| S/s? (2)
Parasitic nemotode (roundworm)
* often self-limiting cause they can't replicate in humans
* however, can form granulomas which can result in irreversible visual loss
175
Dx eye infections? (5)
* swabs for culture = bacterial, chlamydial, viral
* corneal scrapes = bacterial keratitis
* aqueous/vitreous culture in endophthalmitis
* microscopy/culture for acanthamoeba
* serology for toxoplasma or toxocara
176
chloramphenicol mechanism?
| Used for? (2)
Inhibits peptidyl transferase enzyme (stops protein synthesis)
* bacteriocidal = strep and haemophillus
* bacteriostatic = staph
177
chloramphenicol side effects? (3)
* allergy
* irreversible apastic anaemia
* grey baby syndrome
178
Antibiotics that inhibit cell wall synthesis?
B lactams = penicillins and cephalosporins
179
Antibiotics that inhibit nucleic acid synthesis?
Quinolones e.g. ofloxacin (inhibit DNA gyrase)
180
What is a common contaminant in eye drop bottles?
Pseudomonas
181
Bacterial conjunctivitis tx? (3)
* chloramphenicol = treats most bactria EXCEPT pseudomonas
* fusidic acid = treats staph aureus
* gentamicin = treats gram -ve bacteria including coliforms + pseudomonas
182
Example of antiviral drops?
Aciclovir
* used for dendritic ulcers of cornea
REMEMBER NEVER USE STEROIDS
183
Tx chlamydial conjunctivitis?
Topical oxytetracycline
| adults may also need oral azithromycin for genital chlamydia infection
184
Tx bacterial keratitis? (2)
* A 4-quinolone (ofloxacin) = treats coliforms and pseudomonas - however, not effective against strep pneumoniae
* gentamicin and cefuroxime = combo will treat most gram +ve and gram -ve
185
Ax acute red eye? (7)
* conjunctivitis
* keratitis
* anterior uveitis
* scleritis/episcleritis
* acute angle closure glaucoma
* subconjunctival haemorrhage
* cellulitis
186
types of blepharitis?
Anterior (lid margin redder than deeper part of lid)
* seborrhoeic = scales on lashes
* staphylococcal = infection of lash follicle
Posterior (redness is in deeper part of lid, lid margin normal-looking)
* meibomian gland dysfunction (MGD)
187
Blepharitis s/s? (3)
* gritty eyes
* foreign body sensation
* mild discharge
(similar to conjunctivitis)
188
S/s anterior blepharitis? (2)
Seborrhoeic
* lid margin red
* scales
* dandruff
* no ulceration, lashes unaffected
Staphylococcal
* lid margin red
* lashes distorted, ingrowing lashes (trichiasis)
* styes/ulcers of margin
* corneal staining due to exotoxin
189
S/s posterior blephritis (MGD)? (5)
```
Lid margin skin and lashes unaffected
M.G. openings pouting & swollen
Inspissated (dried) secretion at gland openings
Meibomian Cysts (chalazia)
Associated with Acne Rosacea (50%)
```
190
Blepharitis tx? (3)
* Lid hygiene (daily bathing)
* Supplementary tear drops
* oral doxycycline for 2-3 months
Very difficult to eradicate!!
191
Signs of conjunctivitis? (6)
* red eye is diffuse towards fornices
* discharge
* papillae or follicles
* sub conj. haemorrhage
* chemosis = oedema
* pre-auricular glands (if viral)
VISION UNAFFECTED
192
Tx acute bacterial conjunctivits?
| Ax organisms? (3)
Self-limiting (will clear in 14 days) however topical antibiotics will clear faster
* staph aureus
* strep.pneumoniae
* H.influenzae
193
Ax follicular conjunctivitis?
| Tx?
Viral or chlamydial
| * Tx = propine, trusopt
194
what is keratitis?
| Layers of the cornea?
Inflammation of cornea
* epithelium
* stroma
* endothelium
195
Ax corneal ulcers?
Infective (central)
* viral
* fungal
* bacterial
* acanthamoeba
Autoimmune (peripheral)
* rheumatoid arthritis
* hypersensitivity e.g. marginal ulcers
196
s/s corneal ulcers? (8)
* severe pain (except in herpes virus?)
* photophobia
* profuse lacrimation
* vision may be reduced
* circumcorneal red eye
* corneal reflex (reflection abnormal)
* hypopyon
* staining with fluorescein
197
Corneal ulcer tx? (4)
* Identify cause (corneal scrape)
* antimicrobial if bacterial infection e.g. ofloxacin
* antiviral if herpetic e.g. aciclovir
* anti-inflammatory if autoimmune e.g. steroids
198
Causes of anterior uveitis? (4)
Autoimmune
* reiter's, UC, Ank Spondyl, sarcoid
Infective
* TB, herpes simplex, herpes zoster
Malignancy
* leukemia
Other
* idiopathic, traumatic
199
Anterior uveitis s/s? (8)
* Pain (+ referred pain)
* Vision may be reduced
* Photophobia
* Red eye (circumcorneal)
* Cells & flare in anterior chamber
* Keratic precipitates
* Hypopyon
* Synechiae – inflammation in fibrin (small or irregular pupil)
OFTEN MISSED AND TREATED AS CONJUNCTIVITS
200
Anterior uveitis tx? (3)
* topical steroids
* mydriatics e.g. cyclopentolate
* investigate for systemic associations if recurrent or chronic
201
Features episcleritis? (4)
* association with gout
* recurrent
* nodules may occur
* self-limiting
202
Scleritis? (4)
* association with serious systemic vasculitides e.g. rh arthritis + wegener's
* EXTREMELY painful
* violaceous hue
* associted with uveitis
203
How to differentiate between scleritis and episcleritis?
phenylephrine test (epi will blanche with topical phenyl, scleritis will not)
ALSO PAIN = scleritis way more painful
204
Tx scleritis and episcleritis?
Episcleritis
* self-limiting
* lubricants
* topical nsaids
* mild steroids
Scleritis
* oral nsaids
* oral steroids
205
Acute closed angle glaucoma s/s? (5)
* Severe pain!!
* Nausea, headache
* Cornea cloudy
* Pupil mid-dilated
* eye stony hard
206
What group of people are acute closed angle glaucomas common in?
Elderly* hypermetropic – thick glasses
207
Causes of sudden visual loss? (7)
* Vascular aetiology (retinal artery/vein occlusion)
* Vitreous haemorrhage
* Retinal detachment
* Age related macular degeneration (ARMD) -wet type
* Closed angle glaucoma
* Optic neuritis
* Stroke
208
What is the major blood supply to eye?
Branches of opthalmic artery
209
Vascular aetiology sudden visual loss?
OCCLUSION
* retinal artery/vein
* optic nerve circulation
HAEMORRHAGE
* abnormal blood vessels (DM, wet AMD)
210
CRAO s/s? (4)
* Sudden visual loss
* painless
* RAPD (relative afferent pupil defect)
* pale oedematous retina, thread-like retinal vessels
211
Ax CRAO? (2)
It's a type of stroke!
* carotid artery disease
* emboli from heart (rare)
212
Variants retinal artery occlusion? (2)
* Branch retinal artery occlusion
| * Amaurosis fugax
213
What is amaurosis fugax?
S/s? (3)
Tx?
Transient CRAO!
* transient painless visual loss (curtain)
* lasts ~5 mins with full recovery
* usually nothing abnormal on examination
Tx = urgent referral to stroke clinic
214
Ax central retinal vein occlusion? (3)
Virchow's triad
* endothelial damage e.g. diabetes
* abnormal blood flow e.g. hypertension
* hypercoagulable state e.g. cancer
215
What is occlusion of optic nerve circulation called?
| Mechanism?
Ischaemic optic neuropathy (ION)
| * Posterior ciliary arteries become occluded, resulting in infarction of the optic nerve head
216
Ax ION? (2)
* GCA
| * medium to large sized arteries
217
Visual symptoms of ION?
| Why is immediate tx important?
* sudden severe visual loss
* irreversibl blindness
* signs = swollen optic nerve!!
Immediate treatment may prevent bilateral visual loss!!
218
What does sudden visual loss caused by haemorrhage involve?
haemorrhage often occurs into the vitreous cavity – known as a ‘vitreous haemorrhage’
219
Vitreous haemorrhage s/s? (3)
* loss of vision
* floaters
* loss of red reflex
220
Retinal detachment s/s? (4)
* painless loss of vision
* flashes + floaters
* RAPD
* tear on opthalmoscopy
221
Which type of ARMD is associated with sudden visual loss?
* WET
Dry is associated with gradual visual loss
222
S/s wet ARMD? (3)
* rapid central visual loss
* distortion
* haemorrhage/exudate
223
Glaucoma?
| How does it result in visual loss?
Progressive optic neuropathy
| * optic nerve damage
224
Closed angle glaucoma s/s? (7)
* Painful
* red eye
* sudden visual loss
* headache
* vomiting
* cloudy cornea
* dilated pupil
225
Causes of gradual visual loss?
* cataract
* ARMD - dry
* refractive error
* glaucoma
* diabetic retinopathy
226
what is the number 1 cause of preventable blindness worldwide?
Cataract
227
Catarct s/s? (2)
| Tx?
Gradual decline in vision that cannot be corrected with glasses
Glare (can be very disabling at night when driving)
* Tx = surgical removal with intra-ocular lens implant
228
S/s dry ARMD?
* gradual decline in vision
* central vision "missing"
* Drusen - build up of waste
* atrophic patches of retina
229
Dry ARMD tx?
no cure - tx is supportive with low vision aids e.g. magnifiers
230
What is a refractive error?
| Types? (4)
Eyes cannot clearly focus image
* Myopia (short-sighted)
* hypermetropia (long)
* astigmatism (irregular corneal curvature)
* presbyopia (loss of accommodation with aging)
231
Glaucoma open-angle s/s? (4)
* often asymptomatic
* cupped disc
* visual field defect
* high IOP
232
Papilloedema?
specific term meaning swollen optic discs secondary to raised intracranial pressure (ICP)
233
What should all patients with bilateral optic disc swelling be suspected of having?
raised ICP due to a space occupying lesion (SOL) until proven otherwise
234
Pathophysiology papilloedem?
Subarachnoid space around optic nerve continuous with SAS surrounding brain - raised ICP interrupts axons + venous drainage = swollen discs
235
Why is raised ICP a medical emergency?
Further increases in volume causes blood vessels to be compressed, ultimately causing brain ischaemia with herniation through foramen magnum, brainstem compression and death
236
What is a common cause of raised ICP other than SOL?
Hypertnesion - always check blood pressure!!
237
When will CSF result in raised ICP? (3)
* obstruction of CSF circulation
* overproduction of CSF
* inadequate absorption
238
What happens if disc swelling (of any cause) becomes chronic?
Disc swelling subsides, discs become atrophic and pale
| * can result in blindness
239
What is the neurotransmitter of photoreceptors?
glutamate
