Ophthalmic emergencies Flashcards
(243 cards)
1
Q
What is the definition of an ophthalmic emergency?
A
Condition that affects the eye that requires immediate intervention in order to protect the eye and preserve vision
2
Q
What are 4 groups that ophthalmic emergencies can be classed into?
A
- Trauma
- Loss of vision
- Painful red eye
- Double vision
3
Q
What are 2 of the commonest causes of traumatic eye injury today?
A
- sports: ice hockey, racket sports
2. DIY, gardening
4
Q
What proportion of eye injuries occur in the home?
A
50%
5
Q
What proportion of eye trauma is blunt trauma?
A
80%
6
Q
What proportion of eye trauma is perforating injuries?
A
19%
7
Q
What is the definition of blunt eye trauma?
A
no loss of integrity of the globe, no laceration/cut, but compressive trauma to globe
8
Q
What is the definition of a perforating eye injury?
A
Break in integrity of the globe, full thickness cut through cornea or sclera
9
Q
What is the definition of a intra-ocular foreign body?
A
Whatever has caused cut in wall of eye is retained in eye, needs to be removed
10
Q
What are 5 types of eye trauma?
A
- Blunt
- Ruptured globe
- Intraocular foreign bodies
- Chemical burns
- Non-accidental injury
11
Q
What is another way of describing a ruptured globe?
A
Penetrating injuries
12
Q
What are 8 types of blunt trauma in the eye?
A
- Lid avulsion
- Periorbital haematoma
- Blow-out fractures
- Hyphaema
- Sphincter rupture
- Iridodialysis
- Retinal detachment
- Choroidal rupture
13
Q
What is lid avulsion?
A
Lids torn from insertions
14
Q
What is a periorbital haematoma?
A
Bruising around eye, affecting peri-orbital tissues
15
Q
What are blow-out fractures?
A
Fracture of orbital floor, roof (rarely) or walls
16
Q
What is a hyphaema?
A
Blood within the anterior chamber of the eye (between cornea and iris)
17
Q
What is a sphincter rupture?
A
Circular muscle of iris being broken
18
Q
What is iridodialysis?
A
tear of iris away from root
19
Q
What is retinal detachment in eye trauma?
A
Blunt force sufficient to remove retina from inner surface of globe
20
Q
What is choroidal rupture?
A
rupture of major blood vessels in wall of eye
21
Q
What causes blunt trauma to occur in eye injuries?
A
When something makes contact with the eye, because it is a closed structure it squashes eye in an anteroposterior direction and stretches the eye and the equator. Mechanical waves are transmitted through the globe
22
Q
What causes damage to occur in blunt eye trauma?
A
the mechanical waves are transmitted through the globe and damage can occur to any or all intraocular structures
23
Q
What can cause you to underestimate the damage in blunt trauma to the eye?
A
Blunt injury from outside may not look severe but can cause damage to any of these structures in the eye
24
Q
What should be the first step to take in a lid laceration?
A
check that the rest of the eye is OK, no concealed penetration injury to the globe
25
What are 5 types of lid laceration locations that should be referred to the ophthalmologist?
1. Crossing lid margins (edge with eyelashes)
2. Medial canthus (where upper and lower lid meet at nose)
3. Lacrimal apparatus (tear ducts - close to medial canthus)
4. Levator complex (muscles that raise upper lid)
5. Associated with globe perforations should be referred to the ophthalmologist
26
Why do lid margins require special attention in lid laceration?
Any disruption to lid margin can cause problems to the ocular surface itself - need to be carefully repaired
27
How can lid lacerations (other than those that need to be seen by an ophthalmologist) be repaired?
Repair with 6/0 monofilament (same as location anywhere else in body)
28
What must care be taken for when repairing a lid laceration?
No damage by accidental capture of underlying tissues
29
What is another thing to consider when repairing lid lacerations?
Tetanus prophylaxis - give booster if unclear
30
What is the lacrimal punctum of the eye?
Minute openings on the summits of lacrimal papillae on the margin of the eye at the lateral extremity of the lacrimal lake; two lacrimal puncta on the medial (inside) portion of each lid
31
What is the function of the punctum?
hole where tears drain out of eye to the lacrimal sac then drain into the nose
32
Why would it be bad if a lid laceration involving the punctum were not repaired by an ophthalmologist?
If laceration were to be simply repaired, the punctum would never communicate with the lacrimal sac, so the patient would end up with watering of eye forever. Ocular plastic surgeon can pass stents through the punctum and reconstruct the tear drainage system as they repair the lid laceration
33
Why is it important generally for an ophthalmologist/ocular surgeon to repair lid lacerations involving the lid margin/other key parts?
to restore normal anatomy to protect the ocular surface
34
What is the cause of a peri-orbital haematoma?
Direct blow to orbital region; laxity of tissues around eye mean it can become quite swollen
35
What is the management of a periorbital haematoma?
- First: check for other ocular damage (e.g. orbital floor fracture, globe perforation, hyphaema, fundal examination), if bony injury suspected -->X-ray.
- Cold compresses for swelling, analgesia
36
What is a black eye?
a peri-orbital haematoma (large collection of blood within tissue around eye as it is lax)
37
What are 2 considerations for a patient with a black eye?
cause, other structures that may be damaged
38
How long will it take for a peri-orbital haematoma to settle?
Number of weeks
39
What is the cause of blow out fractures?
Direct blow to orbital region
40
Why do blow-out fractures occur?
because the orbit is a confined space, so blunt force to the anterior aspect means the contents are pushed backward. Bones around the orbit are relatively thin, and as intraorbital contents have nowhere to go they push on the walls and cause fractures. Contents can herniate through the fractures
41
What are 4 key symptoms of blow-out fractures?
1. Orbital pain
2. Pain on ocular movements
3. Diplopia
4. Paraesthesia over maxilla
42
What are two things that can cause pain on ocular movements after a blowout fracture?
1. may involve origin of extraocular muscles, pulling on fractured bone when eyes move
2. at time of fracture, bone will open and periorbital tissues will herniate through. As blunt force removed, bony margins close again, pinching periorbital fat/extraocular muscles; as try to move eye, pull against tissue trapped in the fracture
43
What is the cause of diplopia in blow out fractures?
Capture of orbital tissues and restriction of eye movement
44
Where will paraesthesia over the maxilla occur in blow out fracture and why?
Cheek on affected side, because often, infra-orbital nerve (from maxillary branch of trigeminal nerve) affected in these fractures. May be bruising or loss of this nerve
45
What are 5 key signs of a blow out fracture?
1. enophthalmus (sunken into socket)
2. reduced eye movements
3. bony tenderness on palpation around orbital ring
4. surgical emphysema
5. reduced sensation over V2 (maxillary) distribution
46
Why is surgical emphysema a common sign of blow out fracture?
fractures tend to fracture into sinuses around the orbit so easy to get air in the tissues
47
What is the management of blow-out fractures?
Perform X-ray and refer to ophthalmology/ max fax
48
What is a sign often seen on X-rays in blow-out fracture (look on google)?
'tear drop' sign; polypoid mass protruding from floor of orbit into maxillary antrum: is the herniated orbital contents into maxillary sinus, including periorbital fat through fracture in orbital floor
49
What can be helpful when interpreting x-rays in blow-out fractures, as they can be difficult?
Useful to compare right with left
50
What 3 key things will be found on examination in blow-out fracture?
1. Eye movements limited in affected eye due to tissue trapped in fracture --> mechanical tether
2. Pain at extremes of eye movement
3. Enophthalmos (look from above/below)
51
What are the 3 most likely causes of a dilated pupil in the context of trauma?
1. traumatic mydriasis (damage to iris muscle)
| 2. optic nerve problem
52
What will a head CT show in a blow-out fracture?
soft tissue present in ipsilateral maxillary sinus, protrusion of bony fragments e.g. loss of inferior orbital wall; may be fluid level at bottom of right maxillary sinus (blood)
53
What can occur mechanically, secondary to hyphaema?
Stretching of iris tissue, tearing of blood vessels, bleeding into this space
54
What is the cause of a hyphaema?
Direct blow to the eye
55
What are 3 key symptoms of hyphaema?
1. blurred vision
2. watering
3. photophobia
56
What causes reduced vision in hyphaema?
likely to have red blood cells in aqueous humour throughout, adherent to corneal endothelium (inner surface of cornea)
57
What causes watering and photophobia in hyphaema?
blunt force that can cause tearing of iris likely to cause intraocular inflammation
58
What is the key clinical sign of hyphaema?
blood in the anterior chamber - red level of fluid collecting in lower anterior chamber
59
What is the management of hyphaema? 5 elements
1. look for globe perforation (suggests there's been significant trauma)
2. refer to ophthalmologist immediately; usually admitted
3. treatment is bed rest to avoid persistent hyphaema
4. topical steroids to settle inflammation and stabilise blood-aqueous barrier to prevent rebleeds
4. reduce IOP - blood may block trabecular meshwork in anterior chamber angle, requires intensive management
5. secondary bleeds may need surgical evacuation
60
What is the risk of persistent bleeds in hyphaema, which means surgical evacuation may be needed?
Prolonged risk of raised IOP & can be long term staining of corneal endothelium from blood -> may remain opaque after blood removed and need corneal graft
61
What can cause an irregular pupil in trauma to the eye?
Sphincter damage (could be a source of bleeding and hyphaema)
62
What can cause the outline of the pupil not to be perfectly spherical?
can be lumpy due to tears in the circular muscle during blunt trauma, so iris unable to constrict effectively; can also be eccentric shape due to disinsertion of iris from iris root and effectively have 2 pupils (also due to blunt trauma)
63
What is the treatment for when the iris root has been pulled out of its insertion (iridodialysis)?
surgical repair
64
What is the common cause of a ruptured globe?
High velocity injury, blunt or sharp. more likely to involve sharp object at high velocity
65
What are the symptoms of a ruptured globe?
severe pain, loss of vision (sometimes pain may be less)
66
What are 3 key signs of a ruptured globe?
1. subconjunctival haemorrhage
2. full thickness scleral and corneal lacerations
3. prolapse of intraocular contents
67
What are 6 aspects of management of a ruptured globe?
1. tetanus prophylaxis
2. X-ray - assess for intraocular/intraorbital foreign body
3. Plastic shield over eye
4. urgent ophthalmology referral
5. primary repair: restore integrity of globe by stitching holes
6. secondary repair: attempt to restore function if associated retinal problem/ damage to other structures
68
Will all intra-ocular/intra-orbital foreign bodies show up on an X-ray?
no but good place to start
69
Why is a plastic shield put over the eye in a ruptured globe?
not a pad like after surgery; pressure on globe likely to force contents out of perforation in penetrating injuries, so plastic shield prevents pressure on globe
70
What is the underlying dark area in a scleral laceration?
choroid (blood vessels)
71
What can prolapse through a scleral laceration, causing a slit-shaped pupil?
peripheral portion of cornea/cornea-scleral junction, leakage of intra-ocular contents - pupil is pulled off centre
72
If nothing plugs a scleral laceration/ruptured globe e.g. iris, what will happen to the globe?
complete loss of intra-ocular contents and small shrunken globe when patient presents
73
What is the treatment for perforation fo soft tissue of the eye through a scleral laceration?
replace iris/ other tissue within eye, incise tissue if has become necrotic, stitch up hole
74
What can cause the lens to turn cloudy in the case of globe rupture?
corneal perforation; cornea good at self sealing but lens may go cloudy as foreign body passed through cornea and touched lens. Lens clarity maintained by complex ion pump mechanisms (fluid and ion regulation) so will form cataract if mechanisms disrupted and lens clouds
75
What should you be suspicious of in the case of a sudden cataract?
Penetrating eye injury
76
What should be the management of a nail gun causing a nail in the eye?
don't try and pull out; it is touching intra-ocular contents, may be making contact with retina or nerve so important to know where these objects are going before you try and remove them
77
What is the overall aim in the case of intra-ocular foreign bodies?
aim is to remove it regardless of what has gone into the eye
78
What are 6 examples of relatively inert substances as foreign bodies in the eye?
gold, platinum, silver, glass, stone, plastic
79
What are 3 moderately inert substances when foreign bodies in the eye?
lead, zinc, aluminium
80
What is a moderately toxic substance as a foreign body in the eye?
iron
81
What are 6 toxic substances as foreign bodies in the eye?
1. copper
2. thorn
3. twig
4. wood
5. soil
6. hair follicle
82
What is the benefit of knowing what substances are relatively inert when in the eye?
may not cause problems if left in long term whereas more toxic need to come out very quickly
83
What are the most common forms of foreign bodies in the eye?
- iron (steel grinding/ work related, especially without eye protection)
- twigs, thorns, wood, soil - gardening, chopping bush or tree that swings and hits in face
84
What generally causes a foreign body to enter the eye?
High velocity object
85
What are the symptoms of an intra-ocular foreign object? Why can the symptoms be unreliable?
mild to moderate pain, vision may be unaffected; pain is unreliable sign and if goes through sclera unlikely to cause big change in vision
86
What are the possible clinical signs of an intro-ocular foreign object?
may be minimal, entry site may not be obvious/ can be very small, often self-seals
87
What are 4 elements of management of an intra-ocular foreign body?
1. x-ray
2. refer to ophthalmologist
3. systemic antibiotics e.g. ciprofloxacin 750mg bd
4. vitreo-retinal surgery: depends on where it is, normally need to refer to surgeon
88
What are 3 possible signs on examination of an intraocular foreign body?
1. transillumination may reveal hole in iris (see image)
2. dilated pupil and ophthalmoscopy may show foreign body on retina
3. patient may have floater blind spot (or no visual changes
89
Why might it be hard to detect that there is an intraocular foreign body?
cornea has probably self-sealed so no prolapse of contents and not shrivelled eye
90
What are the 2 types of chemical burns to the eye and their effects?
1. Alkalis: rapid penetration (more worrying, rapidly penetrate through intact ocular tissues)
2. Acids: aggregate with proteins - more of a burning reaction which prevents deeper penetration
91
What are 4 symptoms of a chemical burn in the eye?
1. Significant pain
2. Red
3. Photophobia
4. Blurred vision
92
Why will there be photophobia in a chemical burn to the eye?
Due to damage to the cornea and scatter of light, or secondary to intraocular inflammation
93
Why will there be blurred vision in a chemical burn to the eye?
Affects cornea, removal of corneal epithelium which affects focusing of light on the retina
94
What are 5 signs of a chemical burn to the eye?
1. Epithelial loss: can see with fluoroscein sodium and shining blue light, will see green patch
2. Conjunctival injection (hyperaemia) and chemosis (conjunctival swelling)
3. Limbal ischaemia (loss of blood supply to border between cornea and sclera)
4. Corneal clouding
5. Uveitis
95
Why is limbal ischaemia as a result of chemical burns to the eye worrying?
Limbal stem cells mean the cornea can regenerate its epithelium, so this can cause problems to healing in the cornea
96
What are 7 aspects of the treatment of chemical burns to the eye?
1. Copious irrigation with 0.9% NaCl for at least 30 minutes or until neutral pH (compare pH to other eye; may be 4-5L saline)
2. Urgent referral to ophthalmologist
3. Admission dependent on extent of burn
4. Topical and oral vitamin C (for healing)
5. Cycloplegia to dilate, ease pain
6. Topical steroids for surface inflammation
7. Oral antibiotics
97
What are 4 examples of alkalis causing chemical burns that patients may present with?
1. Oven cleaning fluid - sodium hydroxide (pH 14)
2. Drain cleaning fluid - NaOH
3. Plaster - calcium hydroxide (worse if dust than if wet)
4. Fertilisers (some) - ammonium hydroxide (pH 13)
98
Why is it worse if plaster enters the eye in a dry dust form?
It will be localised if it is wet and come out in one go, but if it's from a cloud of dust it can diffusely dissolve into a tear film and be retained in the upper and lower fornices behind the eyelids; can get complete epithelial loss
99
What are 4 examples of chemicals that can cause an acid burn to the eye?
1. battery fluid - sulphuric acid (pH1 )
2. lavatory cleaner - sulphuric acid (1)
3. Bleach - sodium hypochlorite (1)
4. Pool cleaning fluid - sodium hypochlorite (1)
100
What may the cornea/sclera look like in a severe alkali burn (see image)
cornea completely cloudy, eye red, area between sclera and cornea has blanching blood vessels
101
What proportion fo serious eye injuries occur in children under 12, and what proportion of children attending eye casualty have been abused?
35%; 4%
102
How old are most children who suffer from non-accidental eye injury?
Most children under 3 years of age
103
What are the parents of children who suffer from non-accidental eye injury typically like?
Young, single, from poor social circumstances with a history of being abused
104
What is the common mechanism for non-accidental eye injury in children?
shaking or 'shaken/impact'
105
What is the triad of injuries in children that is highly suggestive of physical abuse, typically due to shaking?
1. subdural haematoma
2. retinal haemorrhages
3. brain damage
106
What is the single hallmark sign that a child is being physically abused?
Injuries in different stages of healing
107
What proportion of children who suffer from non-accidental injuries will have permanent physical problems & emotional problems?
Physical: 15%, emotional: all
108
What will a retina look like in a child who has been physically abused?
Retinal haemorhages at multiple layers in retina and multiple sages of healing. Bright red areas of vitreous haemorrhage, remaining areas show some vessels surrounded by fainter, flame-shaped patches of haemorrhages
109
What should be done if you suspect a child is being physically abused?
Have an index of suspicion, flag up to ophthalmologist/ safeguarding person
110
What are 3 types of medical emergencies in the eye?
1. red eye
2. loss of vision
3. double vision
111
What are 6 examples of causes of emergency red eyes?
1. orbital cellulitis (infection within orbit)
2. Microbial keratitis - bacterial infection of cornea
3. endophthalmitis - infection throughout globe
4. corneal melts - most severe of corneal infections, tissue melts and disappears
5. Acute anterior uveitis
6. Acute angle closure glaucoma
112
What are 6 examples of emergency causes of loss of vision?
1. Retinal detachment
2. Central retinal artery occlusion
3. Anterior ischaemic optic neuropathy
4. Giant cell arteritis
5. Papilloedema
6. Accelerated hypertension
113
What are 2 emergency causes of double vision?
Eye movement disorders: acute third nerve palsy and sixth nerve palsy
114
What proportion of red eyes are generally an emergency?
Majority are not an emergency e.g. conjunctivitis, episcleritis, subconjunctival haemorrhages, allergies
115
What is usually the cause of orbital cellulitis?
Infection from neighbouring structures - usually air sinuses (may have history of chronic sinusitis)
116
What can happen mechanically as a result of orbital cellulitis?
ocular structures e.g. nerves and blood vessels get compressed as they're in an enclosed space; this can cause significant optic nerve damage & artery damage
117
What are 6 symptoms of orbital cellulitis?
1. frontal headaches
2. fevers
3. rigors
4. diplopia (large amount of pus behind eye likely to restrict ocular movements)
5. loss of vision
6. feel generally very unwell
118
What are 6 signs of orbital cellulitis?
1. pyrexia
2. lid swelling
3. proptosis (eye pushed forward by collection of pus)
4. Chemosis (swelling of conjunctiva, due to compression of venous drainage)
5. limitation of ocular movements
6. optic nerve compression (blindness is complication)
119
What are 3 possible complications of orbital cellulitis?
1. blindness
2. intracranial abscesses
3. potentially life-threatening if untreated e.g. due to intracranial abscesses
120
What are 4 aspects of the management of orbital cellulitis?
1. Admit for high dose IV antibiotics (often by ophthalmology but also ENT or max fax)
2. Urgent CT scan to assess extent of collection behind eye, determine if needs surgical drainage
3. Bloods: FBC, blood cultures
4. ENT opinion
121
What antibiotics are currently recommended for orbital cellulitis?
IV cefotaxime and flucloxacillin, plus metronidazole if older than 10 years and have chronic sinonasal disease
(clindamycin plus quinolone if penicillin allergy)
Treatment for 7-10 days
122
Why is it even more urgent to request an ophthalmology opinion in children quickly in orbital cellulitis?
The orbital septum is less developed so superficial infection e.g. pre-septal cellulitis or lid infection can rapidly spread to an orbital infection
123
What is pre-septal cellulitis?
Infection of eyelid and periorbital soft tissues
124
What will examination show in orbital cellulitis?
tense tissues around eye, warm to touch, impossible to open eye, if lift lid eye will be red and inflamed
125
What may a CT scan show in orbital cellulitis?
globe pushed more anteriorly on affected side; in black space behind globe there will be a grey area which is the collection, collection in sinuses (grey)
126
How frequently does microbial keratitis occur?
Very common
127
What are 5 examples of gram positive and negative organisms which can cause microbial keratitis?
1. Pseudomonas
2. Pneumococcus
3. Staph.
4. E. coli
5. acanthamoeba
128
What can microbial keratitis occur secondarily to?
corneal injury e.g. foreign body, contact lenses (acanthamoeba if wash in tap water), loose sutures or corneal anaesthesia/exposure
129
What are 5 symptoms of microbial keratitis?
1. pain
2. red
3. discharge
4. photophobia (from secondary inflammation)
5. reduced vision
130
What are 3 signs of microbial keratitis?
1. corneal epithelial defect (detected with use of fluorescein drops)
2. localised white infiltrate (spot) in the stroma
3. hypopyon (in severe cases)
131
What are 6 elements of the management of microbial keratitis?
1. refer to ophthalmologist for admission (ideally same day)
2. corneal scrapes to send for culture
3. intensive topic antibiotics: two types of antibiotics every hour for first 48 hours (including through night) - cultures to find sensitivities
4. isolation cubicle
5. topical steroids may be added to treatment under specialist supervision
6. cycloplegics can be added
132
What can happen secondary to severe microbial keratitis if left untreated, within 48h?
Can develop to corneal melt i.e. cornea tissue disintegrating; likely to follow hypopyon and fluffy white infiltrate in centre of cornea. Unlikely to regain vision/keep eye
133
What is endophthalmitis?
infection throughout entirety of globe
134
What are 2 groups of bacteria that can cause endophthalmitis?
staph sp. and strep sp.
135
What are 2 causes of endophthalmitis?
1. post-operative: cataract surgery or IV injections, usually eyelashes into eye rather than instruments or surgeon
2. secondary to systemic infection aka 'exogenous endophthalmitis'
136
What type of patients are at particular risk of exogenous endophthalmitis?
Immunocompromised patients if infection elsewhere --> haematological spread
137
What are 3 symptoms of endophthalmitis?
Red eye
Pain
Reduced vision
138
When in relation to an operation (Cataract surgery, IV injection) does endophthalmitis tend to occur?
3-5 days post-operatively (doesn't occur in first 24-48 hours)
139
What are 5 clinical signs of endophthalmitis?
1. conjunctival injection (dilated vessels)
2. anterior chamber inflammation
3. hypopyon
4. vitritis (inflammation in vitreous gel)
5. hazy view of the fundus
140
What are 4 aspects of the management of endophthalmitis?
1. Urgent referral to ophthalmologist for admission
2. Aqueous tap/vitreous biopsy and intravitreous antibiotics
3. Intensive topical antibiotics (similar to corneal infection; hourly, two different types)
4. Systemic antibiotics - usually ciprofloxacin
141
What systemic antibiotic is usually given in endophthalmitis?
Ciprofloxacin
142
What are 2 predisposing factors to acute angle closure glaucoma?
1. Hypermetropia
| 2. Hyper-mature (advanced) cataract
143
What is the mechanism which causes AACG?
- reduction in space in front of eye
- secretion of fluid from ciliary body and drainage through anterior chamber drainage angle through trabecular meshwork
- anything that closes up drainage angle is likely to cause increases in intraocular pressure
- inherently short eyeball in hypermetropia, therefore all intraocular structures closer together including angerior chamber drainage angle
- if also advancing cataract --> becoming thicker and thicker and moving iris more anteriorly, pressure in eye will become very high
144
What are 6 symptoms of AACG?
1. very painful
2. poor vision
3. haloes around lights
4. headache
5. nausea
6. vomiting
145
What kind of pain management may be needed in AACG?
morphine
146
What causes haloes around lights in AACG?
Pressure suddenly reaches high level and compromises the cornea; normally can retain clarity due to complex pumping mechanisms regulating fluid and ions in and out of cornea; if pressure high, this is compromised so get oedema of cornea, so vision deteriorates; increased scatter and spread of light, seen as haloes
147
What are 5 clinical signs of acute angle closure glaucoma?
1. reduced vision
2. red eye
3. corneal oedema
4. fixed mid-dilated pupil (oval shaped)
5. closed drainage angle
148
How can the drainage angle be viewed in AACG?
Use contact lenses that deflect light into the cornea of the eye; see if angle open or closed
149
What are the 2 basic things to do to manage AACG?
1. refer to ophthalmologist
| 2. lower intraocular pressure
150
How high might pressure in the eye be in AACG and why is this significant?
60-80mmHg (normal 10-21); if high for longer than a few hours can cause significant, permanent damage to the optic nerve
151
What are 3 ways that the pressure in the eye can be reduced in AACG?
1. Medical: systemic acetazolamide, mannitol, topical pilocarpine, beta blockers
2. Laser: Nd-YAG iridotomy
3. Surgical: iridectomy
152
How does acetazolamide work to treat high IOP in AACG?
carbonic anhydrase inhibitor, diuretic; reduced proportion of aqueous humour
153
How does topical pilocarpine work to lower IOP in AACG?
dilates pupil to pull iris out of the angle
154
What are 4 drugs that can be used to medically lower IOP in AACG?
1. systemic acetazolamide
2. mannitol
3. topical pilocarpine
4. beta blockers
155
What kind of medical management is best to use in AACG when IOP is over 40mmHg?
Most topical therapies won't work until pressure is below 40mmHg so use systemic above this level
156
What does laser Nd YAG Iridotomy involve?
hole in peripheral iris to allow additional route of fluid from posterior chamber to anterior chamber
157
What does a surgical iridectomy involve?
peripheral portion of iris removed
158
How might corneal oedema in AACG appear?
unclear view of iris and speckled appearance of cornea due to corneal oedema; can see bullae, i.e. little collections of oedema; mid-dilated pupil, red eye
159
What are 3 causes/ predisposing factors of retinal detachment?
1. usually result of a retinal tear (rhegmatogenous)
2. myopia
3. trauma
160
What can cause a retinal tear?
Can be secondary to posterior vitreous detachment; happens as vitreous degenerates which occurs in everyone. vitreous gel attached to retina peripherally and around optic nerve; as it shrinks and collapses in on itself, pulls on retina; no problem in most cases (flashing light/ floater as it occurs) but retina left unaffected; in some, causes tear in retina--> fluid passes underneath retina, which can remove it from inner surface of globe
161
Why can myopia cause retinal detachment?
everything pulled further apart and stretched; thinner retina, disposed to breaks
162
How can trauma lead to retinal detachment?
transmission of pressure wave through eye will cause compression and stretching of all intraocular structures including the retina; traction on retina can cause a tear
163
What are 4 symptoms of retinal detachment?
1. flashes
2. floaters
3. shadow/curtain across vision (can't see around or through)
4. painless
164
What is the cause of most flashes and floasters?
occur as posterior vitreous detachment happens
165
What are 3 clinical signs of retinal detachment?
1. field defect
2. reduced central vision if detachment has reached macula
3. visible elevated retina on ophthalmoscopy - elevated/ out of focus areas during scan around fundus (see image)
166
What is a complication of retinal detachment and why?
can lead to complete blindness if untreated; once macula is detached, central vision is lost permanently so the aim is to operate before this occurs
167
What are the 2 types of management of retinal detachment?
SURGICAL management:
1. external approach: scleral buckle
2. internal approach: vitrectomy
168
What does a vitrectomy to treat retinal detachment involve?
surgeon removes vitreous gel, retina placed back against inner surface of eye, then use laser or cryotherapy to stick it down. often put gas or oil bubble to tamponade area of tear and prevent further detachments
169
What is the most common type of management of retinal detachment?
internal approach: vitrectomy
170
What does the external approach/scleral buckle to treat retinal detachment involve?
piece of silicone sponge/rubber/plastic put on outside of scleral; is sewn to keep it in place. pushes sclera in towards eye to reduce pull on the retina, allowing the retinal tear to settle against the wall of the eye. the buckle may cover just that area or form a ring around the whole eye
171
What is central retinal artery occlusion?
when main blood supply to the retina is suddenly occluded
172
What is central retinal artery occlusion (CRAO) usually a sign of?
generally sign of underlying systemic disease
173
What are 4 causes of CRAO?
1. atheroma
2. embolus (carotid artery or cardiac)
3. arteritis
4. raised intra-ocular pressure --> can compress blood vessels when v high
174
What are 2 symptoms of CRAO?
1. preceding amaurosis fugax [transient monocular blindness] if due to an embolus in up to 10%
2. sudden, unilateral, painless loss of vision or field defect
175
What are 5 clinical signs of CRAO?
1. Markedly reduced vision (finger counting)
2. Relative afferent pupillary defect
3. Whitening of the retina with cherry red spot at macula
4. Segmentation of retinal vessels (cattle-trucking)
5. Embolus: may be able to spot with split lamb, white/yellow within vessel
176
What is a key determining factor in the management of CRAO?
Whether patient presents within 8 hours or after more than 8 hours
177
What are 4 possible aspects of treatment for CRAO if patient presents within 8 hours?
1. Ocular massage if patient presents within 90-100 minutes onset
2. Intravenous acetazolamide in combo with:
3. Anterior chamber paracentesis
4. Re-breathing into a paper bag --> to dilate artery
178
What investigations should be performed in CRAO? Group into urgent, mid-term and longer-term
- Bloods: Urgent ESR, CRP (FBC: look at platelets) especially in over 60years, to rule out giant cell arteritis
- Coagulation tests and screening for vasculitides
- In longer term, fasting blood glucose and lipid profile for cardiovascular risk assessment
179
What are 2 aspects of treatment for CRAO both within 8 hours and after, after any immediate treatment?
1. Aspirin
| 2. Refer to TIA or stroke clinic: consider it as a type of stroke (managed in same way)
180
Why does the macula retain a cherry red spot in CRAO?
It is supplied by the intact underlying choroid
181
What are 4 examinations to perform in CRAO to check for systemic signs of related disease?
1. Auscultate carotid arteries for bruit
2. Auscultate heart for murmurs
3. Radial pulse for AF
4. Blood pressure
182
What is the most important underlying diagnosis to rule out in CRAO and why?
Giant cell arteritis - visual loss will be reversible in case of timely intervention, can save fellow eye vision
183
What 2 investigations can be done if there is doubt about the diagnosis of CRAO?
FFA and OCT
184
Why is CRAO an emergency?
Retinal damage becomes rapidly reversible with time
185
What is something key to note about treatment for reversible vision loss in CRAO?
No evidence-based treatment to reverse visual loss in CRAO yet
186
What does ocular massage involve in CRAO?
Firm massage over globe with eyelid shut for 10 seconds with 5 second interludes
187
Look up images of ophthalmoscopy in CRAO
pale retina, discontinuity of blood in blood vessels, cherry red spot macula
188
What is meant by anterior ischaemic optic neuropathy?
Loss of blood supply to the optic disc
189
What is the key consideration in anterior ischaemic optic neuropathy (AION)?
Where it is arteritic or non-arteritic
190
What are the 2 cause of anterior optic ischaemic neuropathy?
1. arteritic: giant cell arteritis
| 2. Non-arteritic: arterio/atherosclerosis
191
What are the symptoms of anterior optic ischaemic neuropathy?
Sudden, painless los of vision
192
What are 5 signs of anterior optic ischaemic neuropathy?
1. Reduced visual acuity
2. Altitudinal visual field defect: upper, lower or horizontal segment of vision
3. RAPD
4. Pale swollen disc with fine haemorrhages (segmental) around disc
5. Later - optic atrophy (pale disc)
193
What is the management of anterior optic ischaemic neuropathy? 2 key aspects.
1. must exclude giant cell arteritis: history, exam, investigations: ESR, CRP, FBC
2. Screen for hypertension and diabetes
194
Look at images of the retina in AOIN.
Pale swollen disc, can't clearly see margin; lost usual pink appearance to tissue
195
Where is the physiological blind spot which normal individuals have?
Infero-temporally where optic nerve passes through retina - no photoreceptors in this area
196
What is key to remember about giant cell arteritis?
Needs URGENT referral any time of day and night
197
What is the cause of giant cell arteritis?
Systemic vasculitis, over 60 age group; can affect other structures such as heart
198
What are 9 possible symptoms of giant cell arteritis?
1. Temporal headache
2. Scalp tenderness (pain brushing hair)
3. Pain on chewing
4. General malaise
5. Anorexia and weight loss
6. Girdle pain/stiffness (associated with polymyalgia rheumatica)
7. Diplopia
8. Sudden loss of vision (transient obscuration for seconds)
9. Night sweats
199
What are 5 clinical signs of GCA?
1. Tender, non-pulsatile superficial temporal arteries (really visible)
2. VI nerve palsy
3. Anterior ischaemic optic neuropathy - altitudinal field defect
200
What are the chances of the other eye getting AOIN if one has it caused by GCA?
70%
201
What are 4 investigations to perform in GCA?
1. ESR
2. CRP (both will be raised)
3. Urine dip
4. Chest x-ray - screening for other sources of infection
5. Temporal artery biopsy - only AFTER diagnosis and treatment started
202
Why might a temporal artery biopsy be inconclusive in GCA?
skip lesions
203
When should a temporal biopsy be done?
Only after diagnosis made and treatment started
204
What are 2 key aspects of management of GCA (after urgent referral)?
1. Admit
| 2. High dose steroids: IV steroids followed by oral
205
What is papilloedema?
bilateral swelling of optic discs due to raised intracranial pressure
206
What are the 2 possible causes of papilloedema?
1. Space occupying lesions
| 2. Idiopathic intracranial hypertension
207
What must be the first action after detection of papilloedema?
referral to general medical team/ neurology team to arrange for relevant neuro-imaging
208
What is the cause of papilloedema in the absence of a space-occupying lesion?
Idiopathic intracranial hypertension
209
Who tends to be affected by IIH?
Younger females
210
What causes IIH?
Increase in CSF pressure for no known reason which presents as swelling of both optic discs
211
What was the previous name for IIH?
Benign intracranial hypertension (not technically benign if untreated --> visual loss)
212
What kind of visual changes can occur wit papilloedema?
Blurred vision, double vision, flickering or complete loss of vision lasting a few seconds
213
What is the management of IIH? 5 features
1. Visual loss if obese
2. Serial lumbar puncture to control raised pressure
3. Acute tx: prednisolone to treat headaches and papilloedema
4. Mild chronic disease: acetazolamide (or other diuretics)
5. Surgical options: optic disc fenestrations, CSF shunting, venous sinus stenting
214
What is accelerated hypertension?
Uncontrolled, undiagnosed systemic hypertension
215
What are 4 symptoms of accelerated hypertension?
1. Asymptomatic
2. Occipital headaches
3. Blurred vision
4. Transient obscurations
216
What are 4 signs of accelerated hypertension?
1. Cotton wool spots
2. Haemorrhages
3. Optic disc swelling
4. Hypertensive encephalopathy (if very acute and severe)
217
What is the management of accelerate hypertension? 4 elements
1. urgent admission for medical therapy, to lower BP and ensure no underlying causes
2. if severe: IV sodium nitroprusside
3. In milder cases: oral nifedipine or atenolol
4. Look for secondary causes of hypertension e.g. renal artery stenosis, phaeochromocytoma
218
Wha is the treatment for severe accelerated hypertension?
IV sodium nitroprusside
219
What is the treatment for milder cases of accelerated hypertension? 2 options.
Oral nifedipine or atenolol
220
What are 2 secondary causes of accelerated hypertension?
1. Renal artery stenosis
| 2. Phaeochromocytoma
221
What is the appearance on fundoscopy of someone with severe hypertensive retinopathy? Look at an image
Swollen optic disc, areas of retinal haemorrhage, vascular attenuation. Areas of exudate radiating away from macula, macular star
222
What is binocular diplopia?
Diplopia that is completely resolved when either eye is closed; caused by misalignment between two eyes
223
What is the underlying cause of binocular diplopia?
Misalignment between two eyes is controlled by extra-ocular muscles, which are controlled by cranial nerves; therefore suggests cranial nerve pathology
224
What does cranial nerve pathology as a cause of binocular diplopia point towards?
severe intracranial problems
225
What is monocular diplopia?
present when only one eye is open (as well as both), caused by disturbances in optical media (often more than 2 images)
226
What are 2 examples of causes of monocular diplopia?
Cataract, debris in vitreous
227
What are 6 causes of eye movement disorders?
1. brainstem disorders
2. cranial nerve palsies
3. hypertension/diabetes (can be transient cranial nerve palsy)
4. intracranial aneurysm or cavernous sinus lesion
5. myasthenia gravis
6. muscle disease
228
What are 4 general symptoms of eye movement disorders?
1. diplopia
2. droopy eyelid
3. dilated pupil
4. neurological etc.
229
What type of diplopia is seen in a) III n. palsy b) IV c) VI
```
III = complicated as multiple branches, depends on extent of damage
IV = vertical
VI = horizontal
```
230
What are 5 clinical signs of third nerve palsy?
1. partial or complete ptosis
2. characteristic down and out position of eye
3. limitation of ocular movements in all directions of gaze other than abduction (controlled by VI)
4. dilated pupil if compressive lesion
5. undilated pupil if ischaemic cause
231
What 2 diseases do ischaemic causes of third nerve palsy relate to?
Hypertension, diabetes
232
Which cause of third nerve palsy will lead to a dilated pupil and which won't?
Compressive cause will lead to dilated pupil, ischaemic will have undilated pupil
233
What is the likely cause of third nerve palsy if it occurs with a dilated pupil (i.e. compressive cause)?
Intracranial aneurysm (most commonly in posterior communicating artery)
234
Third nerve palsy is most commonly caused by an aneurysm in which artery?
Posterior communicating artery
235
What 5 symptoms will be present in a third nerve palsy caused by an intracranial aneurysm?
1. Diplopia
2. ptosis
3. limitation of ocular movements in all directions bar abduction
4. dilated pupil
5. headache - PAIN
236
What are 4 key symptoms of fourth nerve palsy?
1. vertical diplopia
2. head tilt to one side
3. limitation of depression when looking down and in (where superior oblique has maximal effect)
237
What are 2 key symptoms of VI nerve palsy?
1. horizontal diplopia
| 2. limitation of abduction of affected eye
238
What type of clinical signs will brainstem and muscle disease produce, along with diplopia?
complicated eye movements
239
Why does the down and out position of the eye occur in third nerve palsy?
there's still innervation of the lateral rectus (abducts) and superior oblique (depresses) by 6th and 4th nerves
240
What are 3 important initial investigations in 3rd nerve palsy and why?
full neuro exam, BP, blood sugar (BM) - check for pupil dilated, if undilated checking for HTN/DM
241
Who should a patient with III nerve palsy be referred to?
neurologist, neurosurgeon or ophthalmologist
242
What imaging may be performed if a space occupying lesion is thought to be the cause of third nerve palsy?
Cerebral angiogram
243
What are 5 treatment options for third nerve palsy?
1. arterial clips
2. patch
3. Fresnel prisms
4. Botulinum toxin
5. surgery
