Ophthalmology Flashcards
Things that make diabetic retinopathy more likely
Long duration of diabetes Type of diabetes (more common in type 1) Poor glycemic control Increased BP Presence of macro or microalbuminuria Increased serum cholesterol levels Pregnancy Cigarette smoking Genetic factors
Screening for diabetic retinopathy
All diabetics need annual screening
Children screened after five years if have type 1
Increased checks if pregnant
Photographs taken - 2 photos of each eye. Disc centred and macula centred,
Slit lamps used
Why can diabetes lead to blindness
Maculopathy
New vessel formation
Cataracts
CVA with field loss
Stages of diabetic eye disease 0 1 2 3
0- no retinopathy
1- microaneurysms, any exudate, venous loops
2- any microvascular changes, venous beading, multiple blot haemorrhage
3- proliferative disease
What is glaucoma
Chronic progressive optic neuropathy
Thinning of neuroretinal rim of the optic disc results in characteristic cupping of optic nerve head and visual field loss
Risks for primary open angle glaucoma
Age IOP race Family history High myopia Corneal thickness Diabetes Vascular factors eg CV disease, vasospasms, systemic hypotension
Normal intraocular pressure
10-21 mmHg
15.5 average
Optic changes in glaucoma
Enlargement of optic cup
Loss of disc rim
Vascular changes
Peripappillary atrophy
Treatment of primary open angle glaucoma
Control the IOP
Options:
Prostaglandin analogues eg latanoprost. These increase outflow
Beta blockers eg timolol. Decrease production
Carbonic anyhydrase inhibitors eg dorzolamide. Decrease production
Alpha agonists decrease production
Cholinergic agonists eg pilocarpine. Increase trabecular outflow.
Ocular muscles and innervation
Medial rectus- adduction. Third cranial nerve
Lateral rectus- abduction. Fourth cranial nerve
Superior rectus- up. Third
Inferior rectus- down. Third
Superior oblique- fourth
Inferior oblique- third
Horizontal Diplopia cause
Sixth nerve palsy as lateral rectus not working - could be trauma, neoplasms, ischamia, demyelination. Autoimmune disorders
Vertical diplopia
Fourth or third cranial nerve palsy- superior oblique or superior rectus
Causes of a mechanical restriction in eye movement
Trauma leading to orbital floor fracture leading to vertical Diplopia usually
Thyroid eye disease
How to test for RAPD
Swinging light test
Detects if there is paradoxical dilatation of the pupil when light is shone into it due to an afferent defect
Detects an optic neuritis
Causes of optic neuritis
MS or neuromyelitis optica
Blindness by age group 16-64 65-74 75-84 85+
16-64 diabetic retinopathy, macular disorders, optic atrophy, hereditary
65-74 AMD
75-84 glaucoma
85+ cataracts
What eye diseases is smoking linked to?
Cataracts Macular degeneration Thyroid eye disease Retinal vein occlusion Retinal artery occlusion
How do you perform a visual acuity test?
Corrective lenses should be worn
Test each eye individually
Should be 6m away with snellen or 3m with a 3m snellen
Number on chart says distance at which most people can read it
Record as distance from chart over number on chart
Test near vision and colour vision
Charts to measure visual acuity
Snellen
Logmar
Eye symptoms history questions
Has vision been affected When did it start Sudden or gradual Are the eyes uncomfortable Pain? Grittiness, dryness, feel tired- dryness problem Sharp or stabbing pain- ocular surface problems Dull ache- uveitis, raised IOP, scleritis Redness Previous eye history or surgery FH smoking, alcohol, job, driver
Total blindness of right eye- where is lesion
Right optic nerve
Bitemporal hemianopia- where lesion
Optic chiasm- think pituitary tumour
Left visual field loss
Right occipital lobe- could be posterior circulation stroke
Peripheral field loss- what’s the problem
Could be glaucoma
Left homonymous inferior quadrantanopia
Right parietal lobe lesion or stroke
Right homonymous superior quadrantanopia
Left temporal lobe lesion or stroke
What are you looking for on optic disc
Cup
Colour- should be orange with pale centre. Can be pale in optic atrophy eg optic neuritis advanced glaucoma
Contour- circle should be well defined, if not then could be papilloedema
Cataracts
Common cause of visual loss in the elderly
Gradual blurring of distant then near vision
If cataracts is posterior in the lens then they experience glare and vision is better out of sunlight
Correct with surgery and intraocular implant
Younger patients with cataracts
Diabetes, steroid use, chronic uveitis, FH
Primary open angle glaucoma
How does it present
Who is at risk
Progressive painless visual field loss
Risk factor include Afro Caribbean, family history, hypertension
Often picked up by opticians or at glaucoma screening
What are changes in ARMD?
Central vision
Reading, faces and fine detail affected.
Colour is also affected
Dilating agents
Tropicamide
Cyclopentolate
Phenylephrine
Absent red reflex
Cataracts
Retinoblastoma (rare)
Drusen
Lipid deposits
Think ARMD
Flat retina- means not
Not glaucoma as this causes cupping
Retinal haemorrhages
Hypertension
Retinal vein occlusion
Diabetes
In baby could be shaken baby
Retinal elevation
Retinal detachment
Dry ARMD
Gradual loss of central vision
Risk factors- female, smoking, HTN, previous cataracts surgery
Side effects of latanoprost
Blurred vision, stinging, long eyelashes, foreign body sensation, hyperaemia
Eyes and the DVLA
Acuity Glaucoma ARMD Cataracts Optic neuritis Diplopia
Must have at least 6/12 vision
If glaucoma need to inform DVLA so they can do tests to see if safe
Macular degeneration- inform if both eyes affected
Cataracts- don’t need to tell DVLA if still over 6/12
Optic neuritis- tell DVLA
Diplopia- can drive once adaptations of once settled. HGV drivers can’t even with prisms
What is wet macular degeneration
Fluid and or blood develops in the retina
Sudden loss of central vision
Needs instant referral for anti VEGFV injections
Blurred vision Red eye Nausea and vomiting Headache Differential?
Acute angle closure glaucoma
Why blurred vision in AACG
IOP increases leading to oedema of cornea and it becomes cloudy
Therefore affects vision
Who does AACG affect
Long sighted
Female
Treatment of acute angle closure glaucoma
Reduce pressure with drops- acetazolamide
Peripheral iridotomy to restore aqueous flow
Treat other eye prophylactically
Cherry red spot with pale retina
Central retinal artery occlusion
Why does central retinal artery occlusion happen
Non inflammatory vascular problems
Raised cholesterol, HTN, atherosclerosis, diabetes
Alongside angina and TIA
Get smoking Hx, CV exam, routine bloods
Sudden onset of floaters
Most likely to be retinal detachment
Risk factors for retinal detachment
Trauma eg high velocity
Myopia is also a risk
Treatment for retinal detachment
Surgery! Vitreous removed. Flatten retina with gas or oil
Child with eye pain, oedema, erythema, chemosis (swelling of conjunctiva), restricted eye movement, systemically unwell
Orbital cellulitis!
Once identified or suspected orbital cellulitis, what is next step
True emergency! Get senior!
May need referral to oculoplastic team or ENT.
Investigation- blood cultures, swabs, orbital scan, FBC
Cephalosporins or penicillin IV. If abscess present may need surgery
Check obs and visual acuity hourly
Common organisms causing orbital cellulitis
Usually a bacterial infection spread from paranasal sinuses. Commonly staphylococcus aureus, strep pneumoniae, h influenzae. Could be fungal in severely immunosuppressed.
What is a hypopyon?
Red eye, fluid level in anterior chamber of the eye, this indicates an accumulation of WBC
Can be a sign of bacterial keratitis.
Leads to a risk of corneal perforation
Treat with broad spec antibiotics
Red eye, pain and reduced vision
Refer!
Questions with query conjunctivitis
Contact lenses Sexually active (could be chlamydial) URTI recently (indicates probably viral cause) Any contact with people with red eyes Allergies
Symptoms of conjunctivitis
Redness of conjunctiva
Normal visual acuity
Reactive pupils
Mucoid discharge
Tests in conjunctivitis
Swabs- bacterial, viral, chlamydial
Treatment of conjunctivitis
Usually bacterial usually self limiting. 60% resolve in five days without treatment.
Chloramphenicol drops. Ointments and gel provide a higher concentration for longer periods than drops but daytime use is limited because of blurred vision.
Cold compresses
Lubricants
If allergic conjunctivitis then remove trigger. Antihistamines.
If conjunctivitis does not go away after chloramphenicol…
PCR may be required as more likely to be viral or chlamydial
Fluoroscein eye drops would help reveal..
Corneal abrasion, dendritic ulcers and microbial keratitis
Dendritic ulcers
When herpes simplex infects corneal epithelium
Treat with Aciclovir drops
Young male with red eye
Conjunctivitis?
Anterior uveitis? Ask about back pain
Ask about IBD
Investigation into Diplopia
History Tests to measure squint Assess range of eye movements Use Hess chart Do bloods and head scans to determine cause of eye palsy (could be aneurysm, SOL, could be microvascular infarcts)
Treatment of eye palsy
80% of palsies due to microvascular infarct resolve in 6 months. Therefore symptom treatment eg temporary plastic prism can be fitted to patients glasses then Botox into medial rectus muscle to reduce size of squint
Ptosis, eye divergent and depressed. Large pupil
The pupil involvement suggests pressure on nerve rather than microvascular cause
Causes of Diplopia
Poor blood supply, direct pressure on nerve (aneurysm), tumour, head injury, inflammation near nerve
Presence of large pupil as well as nerve palsy, treatment
Indicates Pressure on nerve. Therefore is a medical emergency! This could be dangerous swelling of blood supply in the brain (posterior communicating artery). Imaging required! Go from there.
Trauma to eye area
Could lead to inferior orbital floor fracture. Orbital fat and muscle can get stuck in fracture and lead to diplopia. Get max fax involved, prescribe broad spec antibiotic. Do not blow nose! Ask about loss of sensation below orbit
Variable or progressive weakness of eyelid and ocular muscle
Think myasthenia gravis
Symptoms of optic neuritis
Sudden vision loss
Decreased contrast and colour sensitivity
Pain with eye movement
RAPD
Child with white pupil
Retinoblastoma!
Congenital cataracts
Retinopathy of prematurity
Underdeveloped Retina. The retina is susceptible to the high oxygen that premature babies are often exposed to.
Babies born on or before 31 weeks gestation, under 1500g.
Laser photocoagulation is the treatment of choice.
