Ocular Trauma And Chemical Injuries Flashcards
1
Q
Define the term eyewall
A
Outer fibrous coat (cornea & sclera) of eyeball
2
Q
What are the common sites where extraocular foreign body be impacted?
A
Cornea OR conjunctiva
3
Q
Where on the cornea is extraocular foreign body usually impacted?
A
Embedded in epithelium/superficial stroma
- rarely deep stroma
4
Q
Where on the conjunctiva is extraocular foreign body usually impacted?
A
Sulcus subtarsalis
Fornices
Bulbar conjunctiva
5
Q
Types of extraocular foreign bodies in industrial workers?
A
Particles of iron, emery & coal
6
Q
Types of extraocular foreign bodies in agriculture workers?
A
Husk of paddy & insects
7
Q
Other common extraocular foreign bodies?
A
Dust
Sand
Steel
Glass
Wood
Small insects (mosquito)
8
Q
What are symptoms when an extraocular foreign body is impacted?
A
- Discomfort
- Profuse watering
- Redness
- Pain & photophobia (cornea)
- Defective vision (centre of cornea)
9
Q
What are signs when an extraocular foreign body is impacted?
A
- Marked blepharospasm
- Conjunctival congestion
10
Q
What are the complications when an extraocular foreign body is impacted?
A
- Acute bacterial conjunctivitis
- Corneal ulceration
- Pigmentation or opacity
11
Q
Explain the treatment for corneal foreign body
A
- Under local anesthesia, foreign body removed first with wet cotton swab
- If failed, use hypodermic needle
- If magnetic, use hand held magnet - Patch with antibiotic ointment & eye drops
12
Q
Explain the treatment for conjunctival foreign body (if in fornices or sulcus subtarsalis)
A
Remove with swab or clean handkerchief w/o anesthesia
13
Q
Explain the treatment for conjunctival foreign body (if in bulbar conjunctiva)
A
Remove with hypodermic needle after topical anesthesia
14
Q
What are the causes of blunt trauma?
A
- direct blow to eyeball by fist or any blunt instruments
- roadside accident
15
Q
What are the mechanisms of forces in blunt trauma?
A
- Direct impact on globe
- Compression wave force
- Reflected compression wave force
- Rebound compression wave force
- Indirect force
16
Q
What happens in direct impact on the globe?
A
Max damage at point of impact
17
Q
What is compression wave force in blunt trauma?
A
- Transmitted though fluid contents in all directions
- Strikes ant chamber angle, pushing iris lens diaphragm posteriorly
- Affect retina & choroid also
18
Q
What is reflected compression wave force in blunt trauma?
A
- Compression waves reflect after striking outer coats
- Directed towards post pole -> foveal damage
19
Q
What is rebound compression wave force in blunt trauma?
A
- After striking post globe, compression waves rebound anteriorly
- Causes retinal & choroidal damage (by forward pull)
- Causes lens-iris diaphragm damage (by forward thrust from back)
20
Q
What is indirect force in blunt trauma?
A
indirect forces from the bony walls and elastic contents of the orbit, when globe suddenly strikes against these structures
21
Q
Describe the mechanism of damage in closed globe injuries
A
- Mechanical tearing of tissue of eyeball
- Damage to tissue cells
- Disruption of physiological activity
- Vascular damage leading to ischemia, edema & hemorrhages
- Disturbance to nerve supply
22
Q
What are the corneal lesions seen in close globe injuries?
A
- simple corneal abrasion
- recurrent corneal erosions
- partial corneal tears
- acute corneal edema
- blood staining of edema
23
Q
What are the scleral lesions seen in close globe injuries?
A
- partial thickness scleral wounds
- laceration of sclera
24
Q
What are the anterior chamber lesions seen in close globe injuries?
A
- Injury to iris/ciliary body vessels -> traumatic hyphaema (blood in chamber)
- Exudates -> traumatic uveitis
25
What is the conservative treatment for traumatic hyphaema?
- prevention of rise in IOP & occurrence of secondary hemorrhage
26
What is the surgical treatment for traumatic hyphaema?
Small clears up with conservative only
Large and non-resolved (causing raised IOP) drained to avoid blood staining of cornea
27
[Lesion of iris, pupil & ciliary body]
What is traumatic miosis due to?
Irritation of ciliary nerves
28
[Lesion of iris, pupil & ciliary body]
What is traumatic miosis associated with?
Spasm of accommodation
29
[Lesion of iris, pupil & ciliary body]
What is traumatic mydriasis (iridoplegia) associated with?
Traumatic cyclopegia
30
What are the lesion of iris, pupil & ciliary body in close globe injury?
- traumatic miosis
- traumatic mydriasis
- rupture of pupillary margin
- radiating tears in iris stroma
- iridodialysis
- anteflexion of iris
- retroflexion of iris
31
[Lesion of iris, pupil & ciliary body]
What is iridodialysis?
Detachment of iris from its root at ciliary body -> O-shaped pupil & black biconvex area seen at periphery
32
[Lesion of iris, pupil & ciliary body]
What is anteflexion of iris?
Rotation of detached portion of iris in which its posterior surface faces anteriorly
33
[Lesion of iris, pupil & ciliary body]
What is retroflexion of iris?
Whole of iris is doubled back into ciliary region -> becomes invisible
34
What is the treatment for lesion of iris, pupil & ciliary body?
Atropine
Antibiotics
Steroids
35
In which conditions is atropine contraindicated?
Rupture of pupillary margins
Subluxation of lens
36
[Lesions of Lens)
What is Vossius ring?
Circular ring of brown pigment seen on ant capsule due to striking of contracted pupillary margins against crystalline lens (smaller than pupil)
37
[Lesions of Lens)
What is Concussion cataract?
Absorption of aqueous due to direct mechanical effect of injury of lens fibres
38
[Lesions of Lens)
What does traumatic absorption of lens result in?
Aphakia (sometimes in children)
39
[Lesions of Lens)
Subluxation of lens is due to?
Partial tear of zonules
40
[Lesions of Lens)
Subluxated lens causes?
Trembling of iris (iridodonesis)
Trembling of lens (phacodonesis)
41
What are the lesions of vitreous seen in close globe injuries?
- liquefaction & appearance of clouds of fine pigmentary opacities
- detachment of vitreous ant. at base/post.
- vitreous hemorrhage
- vitreous herniation in ant. chamber
42
What are the lesions of choroid seen in close globe injuries?
- Rupture of choroid
- Choroidal hemorrhage
- Choroidal detachment
- Traumatic choroiditis
43
What are the findings on fundus examination for rupture of choroid?
Whitish crescent (due to underlying sclera) with fine pigmentation at its margins
44
What are the findings on fundus examination for traumatic choroditis?
Patches of pigmentation & discoloration
45
What are the lesions of retina seen in close globe injuries?
- Retinal hemorrhage
- Retinal tears
- Retinal detachment
46
What is open globe injuries?
Full thickness wound of the eyeball (sclera & cornea) includes rupture & laceration
47
What is globe rupture?
Full thickness wound of the eyeball (sclera & cornea) caused by a blunt object
Types = direct and indirect
48
What is indirect rupture?
Compression force resulting in momentary increased in IOP & inside out injury at weakest part of eyeball
49
What are the clinical features of global rupture?
- prolapse of uveal tissue
- vitreous loss
- Intraocular hemorrhage
- dislocation of lens
- IOP raised (initially)
- irregular pupils
- hyphaema
- choroidal rupture
- retinal tears
50
What is the treatment for globe rupture?
1. Repair of tear in eyewall under general anesthesia
2. Post op = antibiotics, steroids, atropine
3. Enucleation for badly damaged eye
51
What is globe laceration?
Full thickness wound of the eyeball (sclera & cornea) caused by a sharp object
52
What is penetrating globe laceration?
single full-thickness wound of the eyewall caused by sharp objects
53
What is perforating globe laceration?
two full thickness wound of the eyewall caused by sharp objects
54
What are the common Intraocular foreign bodies?
- chips of iron & steel
- Particles of glass, stone, lead pellets, copper percussion caps, aluminium, plastic & wood
55
What are the traumatic lesion produced by Intraocular foreign bodies?
- Corneal/scleral perforation, hyphaema, iris hole
- Rupture of the lens & traumatic cataract
- Vitreous haemorrhage and/or degeneration
- Choroidal perforation, haemorrhage & inflammation
- Retinal hole, haemorrhages, oedema & detachment
56
Which inorganic foreign body causes no reaction at all?
inert substances such as glass, plastic, porcelain, gold, silver & platinum
57
Which inorganic foreign body causes local irritative reaction that leads to encapsulation?
lead & aluminium particles
58
Which inorganic foreign body causes suppurative reaction?
pure copper, zinc, nickel & mercury particles
59
Siderosis bulbi is produced by which foreign body?
Iron
60
When does siderosis bulbi occur?
After 2 months to 2 years of injury
61
Explain the mechanism of siderosis bubli
1. Iron particle undergo electrolytic dissociation by current of rest
2. Ions are disseminated throughout eye
3. Ions combine with Intracellular proteins -> degenerative changes (epithelial structures)
62
What are the C/F of siderosis bulbi?
- lens = cataractous
- iris = greenish -> reddish brown
- retina = pigmentary degeneration
- secondary open angle glaucoma
63
Chalosis is produced by which foreign body?
Alloy of copper
64
What is the mechanism of chalcosis?
1. Copper ions dissociates electrolytically
2. Deposited under membranous structures of eyes
3. No chemical combination with proteins, thus no degenerative changes
65
[clinical manifestations in chalosis]
What is Kayser Fleischer ring?
Golden brown ring due to deposition of copper under peripheral parts of Descemet’s membrane of cornea
66
[clinical manifestations in chalosis]
What is sunflower cataract?
Golden green in color & arranged like petals of sunflower
Due to deposition of copper under post capsule of lens
67
[clinical manifestations in chalosis]
What is the manifestation seen in retina?
Deposition of golden plaque at post pole which reflects light with metallic sheen
68
What reaction is seen due to wood/other vegetative materials (organic foreign bodies?
Proliferative reaction characterized by formation of giant cell
69
What reaction is seen due to caterpillar hair (organic foreign bodies?
Ophthalmia nodosum = severe granulomatous iridocyclitis with nodule formation
70
Intraocular foreign body should always be removed, until or unless it is?
- Inert
- Sterile
- Little damage is done to vision
- Removal may be risky
71
What are the conjunctival (extraocular) lesions caused by blunt trauma?
1. Subconjunctival hemorrhage (red spot)
2. Chemosis & Lacerating wound of conjunctiva (tears)
72
What are the eyelid (extraocular) lesions caused by blunt trauma?
1. Ecchymosis of eyelids = due loss SC tissue, blood collected easily -> black eye
2. Laceration of lids
3. Traumatic ptosis
73
What are the lacrimal apparatus (extraocular) lesions caused by blunt trauma?
1. Dislocation of lacrimal gland
2. Lacerations of lacrimal passages (canaliculi)
74
What are the optic nerve (extraocular) lesions caused by blunt trauma?
1. Traumatic papillitis
2. Lacerations of optic nerve
3. Optic nerve sheath hemorrhage
4. Avulsion of optic nerve from back of eye
75
How is optic nerve injuries caused in blunt trauma?
Fractures of base of skull
76
What are the modes of chemical injuries?
1. Domestic accidents
2. Agricultural accidents
3. Chemical lab accidents
4. Deliberate chemical attacks
5. Chemical warfare injuries
6. Self inflicted chemical injuries
77
What are the common acids responsible for acid burns?
- sulphuric acid
- nitric acid
- hydrochloric acid
78
What is the effect of strong acid?
1. Instant coagulation of all proteins which acts as barrier
2. Prevent deeper penetration of acids into tissue
3. Lesion sharply demarcated
79
What are the 3 stages of clinical features of acid burns?
1. Acute ischemic necrosis
2. Reparation
3. Complication
80
What is the C/F of conjunctiva in the stage of acute ischemic necrosis?
- marked edema
- congestion
- widespread necrosis
- copious purulent discharge
81
What is the C/F of cornea in the stage of acute ischemic necrosis?
- sloughing of epithelium
- edema
- opalescence of stroma
82
What is the C/F of iris in the stage of acute ischemic necrosis?
Violently inflamed
- both iris & ciliary body replaced by granulation tissue
83
What is the C/F in the stage of reparation?
- conjunctival & corneal epithelium regenerates
- corneal vascularization
84
What are the complications of acid burns?
- symblepharon
- recurrent corneal ulceration
- complicated cataract
- secondary glaucoma
85
What are the common alkali substances that causes burn?
- lime
- caustic potash
- caustic soda
- liquid ammonia
86
What is the 1st step in managing chemical eye injury?
Prevent further damage through immediate and thorough irrigation
87
How should irrigation be done for a chemical eye injury?
With clean water or saline through IV tubing; at least 2L over 20-30 mins or until pH normalizes
88
What should be done if solid chemical particles are present in the eye (e.g lime)?
Mechanical removal using swab stick
89
What tissues need to be removed in a chemical eye injury?
Contaminated/necrotic corneal epithelium & necrosed conjunctiva
90
Name 3 measures to promote rapid and uncomplicated healing after a chemical eye injury
1. Topical antibiotics
2. Steroid eye drops
3. Lubricant eye drops
91
Why are topical antibiotics (e.g moxifloxacin) used in chemical eye injuries?
Prevent secondary infections
92
What is the role of steroid eye drops in chemical eye injury?
Reduce inflammation, neutrophil infiltration and treat ant. uveitis
93
When should steroid eye drops be used in chemical injuries?
After 2 weeks as steroid may interfere with collagen synthesis
94
What is the use of preservative free lubricant eye drops important in chemical eye injury?
To promote epithelium healing and maintain ocular surface moisture
95
What is the purpose of prescribing doxycycline in chemical eye injuries?
Chelates zinc necessary for collagenase and helps control corneal melting
96
How is symblepharon prevented in chemical eye injuries?
By using a glass shell or sweeping a glass rod in the fornices twice daily
97
What is the treatment for the cornea in thermal injuries?
Atropine
Steroids
Antibiotics
Lubricants
98
What is the effect on conjunctiva in an electrical injury?
Conjunctiva becomes congested
99
What is the effect on cornea in an electrical injury?
Develops punctuate or diffuse interstitial opacities
100
What is the effect on iris & ciliary body in an electrical injury?
Becomes inflamed
101
What is the effect on lens in an electrical injury?
Develops electric cataract after 2-4 months of accident
102
What is the effect on retina in an electrical injury?
Multiples hemorrhages
103
What is the effect on optic nerve in an electrical injury?
develops neuritis
104
What is the effect of UV radiation?
Photo-ophthalmia
Senile cataract
105
What is the effect of infra-red radiation?
Solar macular burns like solar retinopathy
