OPHTHALM Flashcards
(264 cards)
1
Q
What structures are contained in the bony orbits?
A
- The eyeballs
- Extra-ocular muscles
- Nerves
=> Optic, oculomotor, trochlear, trigeminal and abducens - Blood vessels
- (Most of) the Lacrimal apparatus.
- Orbital fat
2
Q
What is the purpose of orbital fat?
A
Fills any space that is not occupied by other structures
Cushions the eye and stabilises the extraocular muscles.
3
Q
What are the three main pathways by which structures can enter and leave the orbit?
A
- Optic canal
- Superior orbital fissure
- Inferior orbital fissure
(There are other minor openings into the orbital cavity.)
4
Q
What goes through the optic canal?
A
transmits the optic nerve and ophthalmic artery.
5
Q
What goes through the superior orbital fissure?
A
transmits the lacrimal, frontal, trochlear (CN IV), oculomotor (CN III), nasociliary and abducens (CN VI) nerves.
It also carries the superior ophthalmic vein.
6
Q
What goes through the inferior orbital fissure?
A
transmits the:
Zygomatic branch of the maxillary nerve,
Inferior ophthalmic vein,
Sympathetic nerves.
7
Q
How can the layers of the eyeball be divided?
A
Fibrous
Vascular
Inner
8
Q
What makes up the Fibrous layer of the eyeball?
What is the main function?
A
The outermost layer.
Consists of the sclera and cornea
Their main functions are to provide shape to the eye and support the deeper structures
9
Q
What is the main function of the sclera?
A
The sclera provides attachment to the extraocular muscles; it is visible as the white part of the eye.
10
Q
What is the main function of the cornea?
A
The cornea is transparent and positioned centrally at the front of the eye; it refracts the light entering the eye
11
Q
What does the vascular layer of the eyeball consist of?
A
the choroid, ciliary body and iris
12
Q
What is the Choroid ?
A
= layer of connective tissue and blood vessels.
provides nourishment to the outer layers of the retina.
13
Q
What is the ciliary body?
A
= comprised of two parts – the ciliary muscle and ciliary processes.
=> The ciliary muscle = a collection of smooth muscles fibres.
=> These are attached to the lens of the eye by the ciliary processes.
The ciliary body controls the shape of the lens, and contributes to the formation of aqueous humour.
14
Q
What is the iris?
A
= circular structure, with an aperture in the centre (the pupil).
The diameter of the pupil is altered by smooth muscle fibres within the iris, which are innervated by the autonomic nervous system.
It is situated between the lens and the cornea.
15
Q
What is the inner layer of the eyeball?
A
= the retina
16
Q
What are the 2 layers of the retina?
A
- Pigmented (outer) layer
2. Neural (inner) layer
17
Q
Neural/inner layer of retina
A
Consists of photoreceptors, the light detecting cells of the retina.
It is located posteriorly and laterally in the eye.
18
Q
Pigmented/outer layer of retina
A
Formed by a single layer of cells.
Attached to the choroid and supports the choroid in absorbing light (preventing scattering of light within the eyeball).
It continues around the whole inner surface of the eye.
19
Q
Where is the non-visual retina?
A
Anterior of the retina
the pigmented layer continues but the neural layer does not
20
Q
Where is the optic part of the retina?
A
Posteriorly and laterally
Both layers of the retina are present.
21
Q
What is the macula?
A
The centre of the retina is marked by an area known as the macula.
It is yellowish in colour, and highly pigmented.
22
Q
What is the fovea?
A
The macula contains the fovea, which has a high concentration of light detecting cells.
It is the area responsible for high acuity vision.
23
Q
What is the optic disc?
A
= the area where the optic nerve enters the retina
it contains no light detecting cells.
24
Q
What is the vitreous humour?
A
= a transparent gel which fills the posterior segment of the eyeball.
has three main functions:
• Contributes to the magnifying power of the eye
• Supports the lens
• Holds the layers of the retina in place
25
What is the hyaloid canal ?
a narrow canal on the vitreous humour, which runs from the optic disc to the lens
this is a foetal remnant which was involved in oxygenation of the lens
26
Lens of the eye
The lens of the eye is located anteriorly, between the vitreous humour and the pupil.
The shape of the lens is altered by the ciliary body, altering its refractive power.
27
What fills the anterior and posterior chambers of the eye?
What does this do?
Aqueous humour
=> Nourishes and protects the eye.
It is produced constantly, and drains via the trabecular meshwork, an area of tissue at the base of the cornea, near the anterior chamber.
28
Where is the anterior chamber of the eye?
The anterior chamber is located between the cornea and the iris
29
Where is the posterior chamber of the eye?
The posterior chamber between the iris and ciliary processes
30
Arterial supply of the eyeball
receives arterial blood primarily via the ophthalmic artery (branch of internal carotid a.)
The ophthalmic artery gives rise to many branches
The central artery of the retina is the most important branch - supplying the internal surface of the retina
31
What is the venous drainage of the eyeball?
the superior and inferior ophthalmic veins.
These drain into the cavernous sinus.
32
What are the 7 extra-ocular muscles?
What are their general functions?
1. Levator palpebrae superioris
2. Superior rectus,
3. Inferior rectus,
4. Medial rectus,
5. Lateral rectus,
6. Inferior oblique
7. Superior oblique.
LPS = superior eyelid movement
All others = eye movement
33
Levator Palpebrae Superioris - attachments
Originates from the lesser wing of the sphenoid bone, immediately above the optic foramen.
It attaches to the superior tarsal plate of the upper eyelid
34
Levator Palpebrae Superioris - innervation
oculomotor nerve (CN III)
35
What is the superior tarsal muscle ?
= a small portion of the LPS muscle, which contains a collection of smooth muscle fibres
HAS SYMPATHETIC INNERVATION
36
Superior Rectus - attachments
Originates from the superior part of the common tendinous ring.
Attaches to the superior and anterior aspect of the sclera.
37
Superior Rectus - innervation
Oculomotor nerve (CN III)
38
Superior Rectus - actions
Mainly elevation of eye.
Also contributes to adduction and medial rotation.
39
Inferior rectus - attachments
Originates from the inferior part of the common tendinous ring
Attaches to the inferior and anterior aspect of the sclera.
40
Inferior rectus - innervation
Oculomotor nerve (CN III)
41
Inferior rectus - actions
Mainly depression of the eye
Also contributes to adduction and lateral rotation.
42
Medial Rectus - attachments
Originates from the medial part of the common tendinous ring
Attaches to the anteromedial aspect of the sclera.
43
Medial Rectus - innervation
Oculomotor nerve (CN III)
44
Medial Rectus - actions
Adduction
45
Lateral rectus - attachments
Originates from the lateral part of the common tendinous ring
Attaches to the anterolateral aspect of the sclera.
46
Lateral rectus - innervation
Abducens nerve (CN VI).
47
Lateral rectus - actions
Abduction
48
Superior Oblique - attachments
Originates from the body of the sphenoid bone.
Its tendon passes through a trochlea and then attaches to the sclera of the eye, posterior to the superior rectus.
49
Superior Oblique - innervation
Trochlear nerve (CN IV).
50
Superior Oblique - actions
Depresses, abducts and medially rotates the eyeball.
51
Inferior Oblique - attachments
Originates from the anterior aspect of the orbital floor.
Attaches to the sclera of the eye, posterior to the lateral rectus
52
Inferior Oblique - actions
Elevates, abducts and laterally rotates the eyeball.
53
Inferior Oblique - innervation
Oculomotor nerve (CN III)
54
Monocular Causes of Acute Painless Vision Loss
```
Acute corneal disease
Acute cataract
Optic neuritis
Vitreous haemorrhage
Ischaemic optic neuropathy
Retinal vein/artery occlusion
Retinal detachment
```
55
Binocular Causes of Acute Painless Vision Loss
```
Pituitary tumour
Optic neuritis
Severe papilloedema
CVA
Migraine
```
56
What is retinal detachment?
= the retina at peels away from its underlying layer of support tissue.
Initial detachment may be localised, but without rapid treatment the entire retina may detach, leading to vision loss and blindness.
It is a surgical emergency.
57
Causes of retinal detachment
- Age
- Post-op/trauma
- Diabetic retinopathy
58
Symptoms of retinal detachment
- Floaters
- Flashes
- Field Loss
- Fall in acuity
+ absent red reflex
59
Treatment of retinal detachment
Refer for urgent surgery (vitrectomy and reattachment)
60
What is vitreous haemorrhage?
= the extravasation of blood into the areas in and around the vitreous humour of the eye
61
Causes of vitreous haemorrhage
- Proliferative diabetic retinopathy
- Retinal tear
- Retinal detachment
62
Symptoms of vitreous haemorrhage
- Floaters = small black dots in vision
| - Absent red reflex (if large bleed)
63
Treatment of vitreous haemorrhage
Vitrectomy and reattachment if necessary
64
What is a vitrectomy?
= removal of the vitreous and replacement it with saline
65
Central Retinal Artery Occlusion - symptoms
Sudden, profound, entire vision loss
66
Central Retinal Artery Occlusion - signs
Relative Afferent Pupillary Defect (RAPD)
Retinal Oedema
Pale retina (ischaemic)
Cherry red spots
+/- carotid bruits
67
Central/Branch Retinal Artery Occlusion - Investigations
To r/o causes of: HTN, DM, Heart problems, GCA
- BP
- FBC, ESR, glucose
- Carotid USS
- Cardiac Echo
68
Central Retinal Artery Occlusion - management
REFER to eye casualty (&TIA clinic)
Rebreathe into paper bag (CO2 dilates vessels)
Ocular massage
Acetazolamide (to decrease IOP)
Paracentesis (to decrease IOP)
69
in which class of drugs is Acetazolamide?
carbonic anhydrase inhibitors
70
Branch Retinal Artery Occlusion - symptoms
Sudden central or sectoral vision loss
71
Branch Retinal Artery Occlusion - signs
RAPD
Field Defect
Signs of hypertensive retinopathy
+/- carotid bruits
72
Branch Retinal Artery Occlusion - management
Refer to eye casualty & TIA clinic
73
Central Retinal Venous Occlusion - symptoms
Blurred, widespread vision loss
74
Central Retinal Venous Occlusion - signs
Widespread retinal haemorrhages
Oedema
Disc swelling
Tortuous veins
+/- cotton wool spots
75
Central/Branch Retinal Venous Occlusion - investigations
To r/o causes of: HTN, DM, Glaucoma, Blood problems
- BP
- FBC, ESR, glucose
- Intraocular Pressure
76
Central/Branch Retinal Venous Occlusion - management
Refer to eye casualty
77
Branch Retinal Venous Occlusion - symptoms
Blurred, central vision loss
78
Branch Retinal Venous Occlusion - signs
Focal retinal haemorrhages
79
Branch Retinal Venous Occlusion - management
Refer to eye casualty
80
What are Mydriatic eye drops?
Dilate the pupil
Short-acting, relatively weak mydriatics, such as TROPICAMIDE (action lasts for up to 6 hours), facilitate the examination of the fundus of the eye.
81
What causes the fundal/red reflex?
caused by light reflecting back from the vascularised retina
82
When might the fundal/red reflex be absent?
ADULTS - cataracts, vitreous haemorrhage, retinal detachment.
CHILDREN - congenital cataracts, retinal detachment, vitreous haemorrhage, retinoblastoma.
83
Haemorrhages causing red eye
1. Sub-conjunctival = blood pools behind the conjunctiva
| 2. Retrobulbar = blood pools behind the eyeball
84
Risk factors for sub-conjunctival haemorrhage
post-surgery,
anticoagulants,
trauma,
URTI
85
Risk factors for retrobulbar haemorrhage
anaesthetic injection,
trauma/perforation => ask if have been using hammer/chisel
86
sub-conjunctival haemorrhage - symptoms
= asymptomatic and harmless
POSTERIOR BORDER VISIBLE
87
sub-conjunctival haemorrhage - management
reassure, resolution in 2 weeks
88
retrobulbar haemorrhage - symptoms
proptosis, decreased eye movement, increased IOP
POSTERIOR BORDER NOT VISIBLE
89
retrobulbar haemorrhage - management
= CT scan needed
90
What are the causes of red eye?
Haemorrhages - subconjunctival/retrobulbar
Vascular congestion - localised/generalised
Acute glaucoma
Trauma
91
Conjunctivitis
= inflamed conjunctiva with bacterial/viral/allergic cause
* Redness in conjunctival fornixes
* Discharge
* Photophobia
* Blanches
• Normal vision, normal pupil, no pain
92
Keratitis
= inflammation of the cornea
* Ciliary redness
* Does not blanche
* Vision blurry/impaired
* Constricted pupil
* Discharge
* Moderate/severe pain
* Photophobia
93
Keratitis - Management
- Steroids (PO/topical) +/- ABX
- Analgesia
UNLESS HSV KERATITIS - DO NOT GIVE STEROIDS (topical acyclovir)
94
Uveitis
= inflamed iris, ciliary body, choroid
* Ciliary redness
* Does not blanche
* Vision blurry/impaired
* Constricted pupil
* No discharge
* Moderate/achy pain
* Photophobia
95
Uveitis - Management
- Steroids (PO/topical) +/- ABX
| - Analgesia
96
Viral causes of conjunctivitis
= Adenovirus, HSV, molluscum
"Gritty" sensation
Watery discharge
Lymphadenopathy
97
How is viral/bacterial conjunctivitis managed?
Chloramphenicol/fusidic acid drops and eye hygiene
98
Bacterial causes of conjunctivitis?
= S. aureus, S. pneumoniae
"Gritty" sensation
Purulent discharge
Lymphadenopathy
99
Allergic conjunctivitis
= hay fever, pollen, dust
Itchy/stingy eyes
Tx = antihistamines
100
When would you consider chlamydial conjunctivitis?
consider if prolonged in young adults
=> STI history
101
Neonatal conjunctivitis
gonococcal/chlamydial infection
can cause permanent scarring and vision loss
102
What can cause keratitis?
Infection – pseudomonas, HSV*
Trauma – foreign body, post-op, perforation
Inflammation – RA/SLE/Wegner’s
103
Risk factors for developing keratitis
contact lenses, dry eyes
104
How is HSV keratitis different from other keratitis?
Causes Dendritic ulcers
DO NOT GIVE STEROIDS (Tx = acyclovir)
105
Complications of keratitis
= corneal ulcer
Can perforate, so needs URGENT REFERRAL and STEROIDS
106
Assessment of Ocular Trauma
1. Thorough Hx – hammer and chisel?
2. Visual Acuity
3. Ophthalmoscopy
4. Slit lamp – check for abrasions
5. Systemic examination (esp. CNS)
6. CT
=> AVOID MRI if possibility of forgein body
107
What is episcleritis?
| What is it sometimes associated with?
= Superficial inflammation of episclera
Associated with autoimmune disease (e.g. SLE)
108
Symptoms of episcleritis
Red Eye
Usually no pain (or if pain, only mild/achy)
Vision not affected
Blanches with phenylephrine
109
Management of episcleritis
Steroid drops/NSAIDs
=> self-limiting
110
What is scleritis?
Deeper inflammation of sclera + episclera
Associated with Infection and connective tissue diseases
111
Symptoms of scleritis
Red eye
Moderate/severe pain
Blurring of vision and photophobia
No blanching with phenylephrine
112
Management of scleritis
Oral steroids
=> needs referral
113
Uveitis
= inflamed iris, ciliary body, choroid
* Ciliary redness (does not blanche)
* Vision blurry/impaired
* Constricted pupil
* No discharge
* Moderate/achy pain
* Photophobia
114
Uveitis - Management
- Steroids (PO/topical) +/- ABX
| - Analgesia
115
How is viral/bacterial conjunctivitis managed?
Chloramphenicol/fusidic acid drops and eye hygiene
116
Foreign body in eye - symptoms and management
Sx = Sudden onset irritation + photophobia
Mx:
=> Eye Casualty
=> FB removal, analgesia, prophylactic ABX
117
Chemical Eye Burn - Signs and Sx
* Pain, redness, irritation, tears
* Inability to keep the eye open
* Sensation of something in the eye
* Swelling of the eyelids
• Blurred vision
=> Complete loss of vision indicates a severe burn
118
Immediate management of chemical burn to the eye
1. Immediate irrigation with water
2. Determine if acid/alkali:
=> Alkali is worse (penetrates the eye more readily to damage external and internal structures)
3. Careful eye inspection
4. Ophthalmology referral – topical ABX and steroids, topical dilators, analgesia, artificial tears.
119
Common causes of blunt trauma to the eye?
= sports injury, automobile accident, fight, job-related injury.
120
Presentations of blunt trauma to the eye?
```
Can present in many ways:
• Hyphaema (can cause acute glaucoma if blocks drainage)
• Periorbital haematoma
• Retinal tear/haemorrhage/detachment
• Traumatic cataract
• BLOWOUT FRACTURE
```
121
What is hyphaema?
blood in anterior chamber of the eye
122
Blowout fracture
Increased pressure in orbital cavity causes floor fracture into maxillary sinus => eye muscles can get trapped
Sx = restricted eye movement, periorbital swelling
Ix = X-ray, CT
Mx = Conservative (unless muscle trapped)
123
Thyroid eye disease
Periorbital oedema,
Eyelid retraction,
Exophthalmos,
Diplopia
124
Orbital cellulitis - symptoms and complications
* Eyelid oedema + erythema
* Painful eye movements/ visual disturbance/ proptosis.
* Systemically unwell
Complications:
• Optic neuropathy
• Orbital abscess,
• Brain abscess/meningitis
125
Orbital cellulitis - management
* Admit to hospital for systemic ABX
| * Monitor optic nerve function
126
Endophthalmitis
= inflammation of the internal eye
Causes:
- Post-op/trauma
RFs
- Immunocompromised
- Blepharitis (=inflammation along the edges of the eyelids)
127
What is blepharitis?
=inflammation along the edges of the eyelids
128
Management of Endophthalmitis?
Intravitreal ABX
129
Idiopathic orbital inflammatory disease
= non-infectious/neoplastic inflammation
(therefore a diagnosis of exclusion)
Symptoms:
- Rapid onset, painful, periorbital oedema
- Eye muscle paralysis
Management:
- Steroids
130
Features of a swollen optic disc on fundoscopy
- Blurred disc margin
- Haemorrhages around disc
- Smaller cup:disc ratio
131
Causes of swollen optic disc
- Optic neuritis
- Papilloedema
- Malignant HTN
- GCA / Arteritic anterior Ischemic Optic Neuropathy
- Non-arteritic AION
132
What is optic neuritis?
What can cause it?
Inflammation of the optic nerve,
caused by:
- Idiopathic
- Infection – syphilis, HSV, mumps
- Demyelination – MS
- SLE/sarcoid, DM
- Ischaemia (GCA)
133
Optic neuritis - symptoms
UNTILATERAL:
- Blurred vision and decreased acuity
- Central scotoma
- Red desaturation
- RAPD
- Pain on eye movement
+/- neuro Sx like numbness
134
Optic neuritis - management
= steroids
135
What is papilloedema?
Swollen optic disc due to raised ICP.
Causes:
- Brain tumour/abscess
- Head injury/brain bleed
- Meningitis/encephalitis
- Idiopathic
136
Papilloedema - symptoms
BILATERAL:
- Transient blurred vision
- Gradual, progressive field loss
- Enlarged blind spot
- Headache/vomiting
137
Papilloedema - management
= investigate and treat underlying cause
138
Swollen optic disc due to Malignant HTN
= swollen disc due to rapid increase in BP to >180/120, and fundoscopy features of hypertensive retinopathy
139
What are fundoscopy features of hypertensive retinopathy?
Grade I – subtle arterial narrowing
Grade 2 – AV nipping
Grade 3 – cotton wool spots, haemorrhages, exudates
Grade 4 (malignant) – above features and also swollen optic disc.
140
Malignant HTN - Sx
BILATERAL:
- Decreased acuity
- Headache
- Eye pain
- +/- focal neuro signs
141
Malignant HTN - Mx
= hospital admission and antihypertensives.
142
GCA / Arteritic AION
= Inflammation and occlusion of vessels supplying the optic nerve, causing infarction.
UNILATERAL (may become bilateral):
- Headache
- Jaw/temportal pain
- SUDDEN VISION LOSS
143
GCA / Arteritic AION - Diagnosis and Mx
Investigations:
- Raised ESR/CRP
- Also check cholesterol/TGs, glucose, BP
Mx = EMERGENCY, high-dose steroids
144
Non-arteritic AOIN
= occluded posterior cerebral artery causing optic nerve infarction
Caused by atherosclerosis (DM, HTN, increased lipids).
Symptoms – UNILATERAL SUDDEN VISION LOSS
145
Non-arteritic AOIN - diagnosis and Mx
Investigations:
- ESR (norma)
- Cholesterol/TGs, glucose, BP
Management = Treat cause, aspirin
146
Optic nerve atrophy
= death of optic nerve fibres
Cause = Compression or decreased blood supply
- Optic neuritis, ischaemia, glaucoma
- Chronic papilloedema
Ix = MRI/CT
147
What is the most common cause of vision loss in the younger population?
Diabetic retinopathy
148
Diabetic retinopathy - pathophysiology
1. Hypoperfusion of retinal vessels
=> ischaemia
2. Pericyte death in vessels
=> Causes weakened walls, causing microaneurysms and oedema
3. Macrophage accumulation to clear debris
=> Causes exudates.
4. A-V shunts open to overcome hypoxia
=> Causes intra-retinal microvascular abnormalities
5. Neovascularisation:
=> Release of VEGF due to hypoxia causes growth of abnormal, weak vessels
=> Leads to haemorrhages
149
Diabetic retinopathy - Risk factors
- Duration and poor control of DM
- HTN / renal disease
- Pregnancy
- Age
- Lifestyle – smoking/alcohol/diet
150
What are the forms of diabetic retinopathy?
1. Non-proliferative (NPDR)
2. Pre-proliferative
3. Proliferative (PDR)
4. Diabetic Maculopathy
151
Non-proliferative DR - Features
Asymptomatic
Features:
- microaneurysms,
- exudates,
- haemorrhages (dot, blot, flame),
- cotton wool spots (infarcted axons)
If severe or pre-proliferative – intraretinal microvascular abnormalities (IRMAs)
152
Non-proliferative DR - Management
- Diabetes control = most important!
| - Careful monitoring
153
Proliferative DR - Features
Asymptomatic until haemorrhage occurs.
Features:
- Irregular new vessels (over disc or elsewhere)
- Haemorrhage (vitreous or pre-retinal)
- Neovascularised iris
154
Proliferative DR - Management
- Diabetes control = most important!
| - Pan-retinal laser photocoagulation (PRP)
155
Pan-retinal laser photocoagulation (PRP)
= use of a laser to burn away peripheral photoreceptors, to decrease O2 demand and decrease VEGF release and creation of new vessels.
Start far out, review in 4-6 weeks and then burn further if needed.
156
Diabetic Maculopathy
When retinopathy affects the macula.
Features:
- Focal or widespread retinal oedema.
- Affects vision
157
What eye diseases other than retinopathy does DM pre-dispose people to?
- Increased risk of eyelid infections
- Increased risk of cataracts
- Delayed healing of abrasions/ulcers/wounds
158
What is the most common cause of vision loss in the UK?
What kind of vision loss does this condition cause?
Age-related Macular Degeneration
Causes progressive, irreversible, CENTRAL vision loss.
159
Investigations in ?AMD
1. Eye examination – fundoscopy, acuity, central visual field test (Amsler grid).
2. Fundus Photos
160
Dry AMD
~90% of AMD
Gradual vision loss (years)
Pathophysiology:
=> Lipid debris thickens Bruch’s membrane = DRUSEN
=> Retinal Pigment Epithelium atrophy = pale areas on retina
161
Dry AMD - Management
Ophthalmology referral
Counsel patient:
• Cannot predict how bad it will get
• Tx does not reverse damage, just stops progression
• Impact – struggle to recognise faces, difficulty reading & driving, increased falls risk
• Smoking cessation
Low-level visual aids
Consider antioxidant supplements
162
Wet AMD
~10% of AMD
Sudden, severe vision loss (months), starting with distorted images.
Pathophysiology:
- New, abnormal vessels pierce Bruch’s membrane
- Leak fluid and blood = oedema, haemorrhage & RPE detachment
- Fibrotic tissue
163
Wet AMD - Management
Anti-VEGF
Focal laser photocoagulation – destroy areas of neovascularisation
164
Cataracts
= clouded opacity on/within the lens due to liquefaction of lens content.
165
Causes of cataracts
Age = leading cause
```
Trauma
Metabolic – DM, Wilson’s disease
Toxins
Systemic disease
Maternal infection
Hereditary
```
166
General symptoms of cataracts
- Decreased acuity and blurring
- Increased myopia
- Faded colours
- Trouble with bright lights and night vision
167
Cataracts - diagnosis
Hx
| Slit lamp examination
168
Cataracts - management
depends on the impact on the patient’s life (occupation/driving/ADLs)
1. Patient Assessment
=> Assess refractive power of current lens
=> Eye health (?any concurrent glaucoma/AMD)
2. Phacoemulsification:
=> US waves emulsify cataract, which is then removed via incision
=> Corrective intraocular lens inserted
169
Possible complications of cataracts op
```
Possible complications:
• Post-capsule opacification
• Retinal detachment
• Vitreous loss
• Endophthalmitis
```
170
Glaucoma
= diseases causing characteristic damage to the optic disc, usually use to increased IOP (>21mmHg).
171
Normal-tension glaucoma
there is normal IOP but the disc is damaged
172
Normal cycle of aqueous fluid
1. Ciliary bodies secrete aqueous into the posterior chamber.
2. Passes through the iris into the anterior chamber
3. Drained via the trabecular meshwork in the anterior angle
173
Where is the anterior angle?
= the angle between the iris and the cornea.
174
Open Angle Glaucoma
Wide anterior angle allows increased aqueous entry but there is decreased drainage (aging may cause sclerosis of meshwork).
=> Increased IOP damages optic nerve fibres.
175
Open Angle Glaucoma - symptoms
Asymptomatic until almost blind => need screening
Visual field loss
=> Superior arcuate scotoma
=> Progress to tunnel vision => blindness.
176
Open Angle Glaucoma - investigations
Visual fields – progressive decrease
Fundoscopy – optic disc changes
IOP (tonometer) – >21 mmHg
177
Optic Disc Changes in Glaucoma
• Increased cup:disc ratio (>0.3/0.4)
• Oval cup
=> Normally the neuro-retinal rim is thickest Inferiorly and thinnest Temporally (I > S > N > T)
=> If the optic disc doesn’t follow the ISNT rule, then there may be glaucomatous damage.
• Disc atrophy
178
Open Angle Glaucoma - management
aim is to prevent further loss, not reverse!
1. Medical Eye Drops (in order of use)
• PG analogues (e.g. iatanoprost) = increase drainage
• Beta-blockers (Timolol) = decreased production
• Carbonic anhydrase inhibitors (Acetozolamide) = decreased production
• Alpha agonist = increase drainage and decreased production
2. Laser Trabeculoplasty
3. Surgical Trabeculectomy
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What is a surgical trabeculectomy?
involves making a hole in the sclera so the aqueous can drain into reservoir/bleb under the surface.
180
What is a laser trabeculoplasty?
use a laser to unblock the trabecular meshwork
181
Angle Closure Glaucoma
Narrow anterior angle becomes suddenly blocked, preventing drainage.
= EMERGENCY
Trigger is usually entering darkness and pupil dilating.
182
Angle Closure Glaucoma - presentation
Sudden onset:
- Acute pain + red eye
- Blurred and decreased vision
- Headache, nausea, vomiting
- +/- prodromal “halos” around bright lights
Signs:
- Sudden increase in IOP (to 70/80 mmHg)
- Red eye
- Clouded lens
- Fixed, mid-dilated pupil
183
Risk factors for angle closure glaucoma
| "CLOSE"
```
Children (FHx)
Long-sighted
Old age
Shallow anterior chamber
Ethnicity (Asian)
```
184
Angle Closure Glaucoma - Management
1. URGENT HOSPITAL ADMISSION
2. Medical:
=> Acetazolamide +/- timolol (decrease aqueous production)
=> Pilocarpine (pupil constriction opens drainage angle)
!!! also give prophylactically to other eye !!!
2. Surgical:
=> Peripheral laser iridotomy
=> Trabectulectomy.
185
Peripheral laser iridotomy
involves burning a hole in iris to allow drainage and the angle to reopen in angle closure glaucoma
also done prophylactically in other eye
186
What is orthoptics?
= diagnosis and management of binocular vision and eye motility disorders.
187
Manifest Squint
Heterotropia
= the visible deviation of one eye when eyes are open
=> ALWAYS PATHOLOGICAL
188
Manifest Squint - Sx
diplopia in adults,
| suppression in children.
189
Manifest Squint - Dx
= cover test (bad eye fixes centrally when good eye is covered)
190
Concomitant squint
Squint is the same irrespective of the gaze direction.
Causes = retinoblastoma, congenital cataract, Down’s
Childhood onset and lifelong
191
Incomitant squint
degree of squint varies with gaze direction (increases when looking in the direction of affected muscles).
Causes = nerve palsies (CN 3, 4, 6) causing EOM paralysis
=> Sudden diplopia +/- neuro signs.
192
Exotropia
Eye points temporally/outwards at rest
Moves nasally/inwards when opposite eye is occluded
193
Esotropia
Eye points nasally/inwards at rest
Moves temporally/outwards when opposite eye is occluded
194
Hypertropia
Eye points superiorly at rest
Moves inferiorly when opposite eye is occluded
195
Hypotropia
Eye points inferiorly at rest
Moves superiorly when opposite eye is occluded
196
CN III Palsy - signs
Ptosis – levator palpebrae
Down & out – SR, IR, MR, IO affected
There can be an efferent pupil defect (DILATED) or can be PUPIL-SPARING
197
CN III Palsy - causes
```
Tumour
CVA
Orbital trauma
Demyelination
Posterior Cerebral Artery aneurysm
```
198
CN IV Palsy - signs
Up & in – SO muscle affected
Compensatory head tilt
199
CN IV Palsy - causes
Trauma = most common
```
Also:
Tumour
CVA
Demyelination
PCA aneurysm
```
200
CN VI Palsy - signs
Eye Adducted – LR muscle affected
201
CN VI Palsy - causes
```
Tumour
CVA
Orbital trauma
Demyelination
PCA aneurysm
```
202
Latent Squint
Heterophoria
= tendency for eye deviation, BUT normally compensated
This is present in most people
203
Latent Squint - Sx
If decompensated, can get:
- headache,
- eye strain,
- diplopia
204
Latent Squint - Dx
cover-uncover test
| bad eye deviates to “rest” when covered, returns to central when uncovered
205
Latent Squint - Mx
If symptomatic - orthoptic exercises and prism
206
Management of squints
1. Correct refractive error
=> CONVEX lenses for CONVERGENT squints
=> CONCAVE lenses for DIVERGENT squints
2. Surgery to realign EOM
=> If no refractive error/lenses don’t help
207
What is amblyopia?
“Lazy Eye”
| = reduced vision in one eye.
208
Causes of amblyopia
= lack of stimulation during critical period of visual development
- Strabismic – brain ignored image from squinting eye (suppression)
- Stimulus deprivation – something blocks image reaching retina (e.g. ptosis, cataract)
- Anisometropic – difference in refractive errors of >1 dioptre (worse eye becomes “lazy”)
209
When is the critical period of visual development?
birth – 7/8 years
210
Amblyopia - Management
If treated in critical period, can reverse amblyopia.
| => Occlusion of good eye with eye patch
211
What causes pupil dilation/mydriasis?
Dilator Pupillae muscle - Sympathetic innervation
212
What causes pupil constriction/miosis?
Sphincter Pupillae - parasympathetic innervation
213
Afferent and Efferent pathway of pupillary light reflex
Afferent = optic nerve (CN II)
Efferent = fibres running ALONG the oculomotor nerve (CN III)
214
Consensual Pupil reflex
= light in one eye stimulates the efferent pathways to both.
2nd order neurons connect pretectal nucleus to BOTH Erdinger-Westphal Nuclei, stimulating efferent pathways
215
Efferent pupillary defect
the affected pupil will never constrict
216
Afferent pupillary defect
= both pupils will constrict a bit, but the “bad” eye less.
217
Accommodation Reflex
Initiated by blurred vision +/- close object
- Ciliary muscles contract
- Zonula fibres relax
- Lens becomes more globular
=> Leads to increased refractive power.
218
What does maximum accommodation depend on?
depends on lens flexibility (this decreases with age).
219
Components of accommodation reflex
Components:
1. Accommodation – constrict ciliary muscle (= CN 3)
2. Constriction – sphincter pupillae (= CN 3)
3. Convergence – medial and lateral rectus (= CN 3 and 6)
220
Horner's Syndrome - Sx
```
Miosis (constriction)
Partial Ptosis (tarsal muscle affected, but not LPS)
Anhidrosis
```
221
Horner's Syndrome - causes
LESION OF SYMPATHETIC CHAIN:
```
Pancoast tumour
Cervical rib
Carotid aneurysm
Neck trauma
CNS disease
```
222
Adie Pupil - Sx
Mydriasis
Light-near dissociation
+/- decreased tendon reflexes
223
Adie Pupil - causes
Post-ganglionic parasympathetic lesion
=> Mostly post-viral/bacterial Infection
224
Argyll-Robertson Pupil - Sx
Small, irregular pupils
| Light-near dissociation
225
Argyll-Robertson Pupil - Causes
Neurosyphilis
226
What is Marcus-Gunn Pupil
= Relative Afferent Pupillary Defect
pupils respond differently to light stimuli shone in one eye at a time in a swinging flashlight test
227
Marcus-Gunn Pupil / RAPD - Causes
Optic neuritis
MS (demyelination)
Ischaemia to optic nerve (e.g. GCA)
Trauma
Tumour
CVA
228
What is light-near dissociation?
Pupillary light reaction is impaired while the near reaction (accommodative response) remains intact
229
What is visual acuity?
What is normal distance VA?
= the ability of the eye to distinguish shapes and the details of objects at a given distance.
6/6 Snellen = average vision
230
What is the range of visual acuity?
6/4 => 6/60 => 3/60 => 1/60
=> Count Fingers => Hand movements
=> Perception of light (PL) => No Perception of Light
231
Conditions for Emmetropia
= perfect focussing onto retina
- 60D = 40D (Cornea) + 20D (Lens)
- Axial length: 22.22mm
232
Ametropia
= some form of refractive error
Hypermetropia/ Myopia
233
Myopia
Short-sighted – light focusses in front of the retina.
=> Refractive – eye refraction too strong (>60D)
=> Axial – eyeball too long (>22.22mm)
234
Myopia - risk factors
Chinese ethnicity
| Lots of close work/time indoors?
235
Myopia - complications
increased risk of retinal detachment
236
Myopia - correction
DIVERGENT/CONCAVE (negative) lens
237
Hypermetropia
Long-sighted – light focuses behind the retina.
=> Refractive – eye refraction too weak (<60D)
=> Axial – eyeball too short (<22.22mm)
238
Hypermetropia - risk factors
infants (but corrects as eyeball grows)
239
Hypermetropia - complications
acute angle closure glaucoma
240
Hypermetropia - correction
CONVERGENT/CONVEX (positive) lens
241
Astigmatism
= unevenly shaped eyeball
=> asymmetry causes different degrees of refraction and 2 focus points
242
Astigmatism - correction
Cylindrical lens
- Has refractive power in only 1 meridian
- Can be used in conjunction with a spherical (convex/concave) lens
=> Combination of spherical and cylindrical lens = toric lens
243
Presbyopia
= loss of accommodation due to thickening and sclerosis of lens with age (>40 years).
=> At ~55 years accommodation is essentially zero.
Correction = “add on” positive lens for reading
=> combined with distance prescription = bi/varifocals
244
Vision rules for driving
Minimum 6/12 vision with glasses and both eyes open
Read number plate from 20m
Sufficient visual fields
CANNOT DRIVE WITH DOUBLE VISION
245
Stereopsis
= the overlap between the eyes, allowing depth perception
246
Blind spot
= where the optic nerve leaves the retina
Not normally noticed due to overlap in visual fields
247
What is the Visual Pathway?
- Axons of retina converge to become optic nerve
- Behind the retina, it becomes myelinated.
- Passes through the optic chiasm and becomes optic tract
- Fibres reach Lateral geniculate nucleus in thalamus
- Rotation of fibres 90o inwards
=> Superior retinal fibres => medial
=> Inferior retinal fibres => lateral
- Fibres rejoin to form optic radiation and rotate back to original position.
248
Blood supply to visual cortex
= posterior cerebral artery
The medial part is also supplied by occipital branch of middle cerebral artery (protects fibres from macula in the event of a PCA occlusion).
249
general rules of visual field loss
Any lesion in optic chiasm = BILATERAL LOSS
Any ONE-SIDED LOSS (homonymous) = retro-chiasmal and will be contralateral to the lesion
QUADRANTANOPIAS = temporal or parietal lobe lesions
250
Where is the location of the lesion causing bitemporal hemianopia?
= optic chiasm lesion
- Pituitary tumour,
- Rathke’s pouch meningioma
- Craniopharyngioma
251
Where is the location of the lesion causing homonymous hemianopia?
= optic tract lesion
Defect will be on opposite side to lesion
252
Where is the location of the lesion causing Superior Quadrantanopia ?
= temporal lobe lesion (inferior fibres capture superior visual field)
Defect will be on opposite side to lesion
253
Where is the location of the lesion causing Inferior Quadrantanopia ?
= parietal lobe lesion (superior fibres capture inferior visual field)
Defect will be on opposite side to lesion
254
Where is the location of the lesion causing visual field defect with macular sparing ?
Lesion of PCA but spared MCA
255
Red Flag Eye Symptoms
* Eye pain (moderate-severe)
* Photophobia
* Sudden and persistent (>60 minutes) visual loss
* Red eye (especially if associated with pain and/or loss of vision)
* Trauma to the eye
256
Questions to ask about visual disturbance
- One or both eyes affected?
- Onset – sudden or gradual?
- Constant or does it come and go?
- How severe is the disturbance?
- Does anything make it worse / better?
- Does the visual disturbance affect distance or near vision, or both?
- Is a specific area of vision affected? (e.g. peripheral, central)
- Any double vision?
=> Images side by side / on top of each other / oblique angle?
- Any positive visual symptoms?
- Any visual distortions?
257
What are "positive" visual symptoms?
- Flashing lights or floaters
- Presence of a “black curtain” across field of vision
- Glare from low sun/car headlights
- Halos around lights
258
What are some visual distortions?
Straight lines appearing wavy
Sparkling lights moving across the visual field
Objects appearing larger or smaller than they really are
259
Questions to ask about Eye Pain
- Site (one/both, where?)
- Onset (how, when, sudden/gradual)
- Character (dull/achey/throbbing/sharp/worse on movement?)
- Radiation
- Associated Sx (N&V, headache, eye Sx)
- Time course (change? getting worse?)
- Exacerbating/relieving Factors:
- Severity of pain
260
Questions to ask about Eye Trauma
Determine mechanism of injury
=> Blunt, chemical, sharp
Document use of power tools/hammer and chisel/absence of safety goggles
Determine the size, speed and nature of the flying object
261
Past Ocular Hx
Ask about previous episodes similar to their current presenting complaint.
Other eye problems/diagnoses.
Ask if the patient uses prescription glasses and if these are used for distance or near vision.
Ask if the patient uses contact lenses
262
What does red desaturation indicate?
Optic neuritis
loss of colour vision (especially red) in the affected eye
263
Periorbital vs. Orbital cellulitis
Have overlapping symptoms (e.g. swelling, erythema) but orbital cellulitis will present with more eye symptoms
=> pain on eye movement / visual disturbance / proptosis.
264
Management of blepharitis
Hot compresses to eyelid margin and removal of debris with cotton buds dipped in cooled boiled water
+ Artificial tears if patients report dry eyes.
