Eye (ENT 3) Flashcards
What is the uvea?
Pigmented part of the eye:
Iris
Ciliary body
Choroid
What is the anterior and posterior uvea?
Iris and ciliary body = anterior uvea
- Inflammation is called anterior uveitis / iritis
Choroid = posterior uvea
- Inflammation is posterior uveitis / choroiditis
What is intermediate uveitis?
Affects vitreous = gel like substance that accounts for 80% of the volume of the eye
What are some associations of anterior uveitis?
HLA B27 syndromes: Ankylosis spondylitis Stills (JIA) IBD Psoriatic arthritis Reactive arthritis Behçets Sarcoid
What is the most common cause of uveitis and most likely to present with a red eye?
Anterior uveitis
How does anterior uveitis present?
Red eye
Pain
Blurred vision
Photophobia
Describe how the red eye develops in anterior uveitis?
Starts with conjunctival infection around the junction of the cornea and slcera and increased lacrimation (but not sticky discharge, unlike conjunctivitis)
How is anterior uveitis diagnosed?
Slit lamp with dilated pupil - shows leucocytes in anterior chamber
What is the management of anterior uveitis?
Urgent eye clinic
Prednisolone 0.5-1% / 2hr - to reduce pain, redness and exudate
Cyclopentolate 1% / 8hr - to prevent adhesions between lens and iris (synechiae) and to relieve spasm of ciliary body
What can happen if there is prolonged inflammation of the eye following anterior uveitis?
Disrupts flow of aqueous leading to glaucoma
+/- adhesions between lens and iris
Why is posterior uveitis not painful (unlike anterior uveitis)?
Choroid is not innervated by sensory nerves
What is the conjunctiva?
Mucus membrane that lines the inside of the eyelids and the sclera
What are some causes of conjunctivitis?
Infective:
Bacterial
Viral
Non-infective:
Allergic
What is it called when there is inflammation of the conjunctiva and the cornea?
Keratoconjunctivis
How does conjunctivitis present?
Red eye Discharge Burning FB sensation Photophobia Itching
Compare bacterial vs viral conjunctivitis
Bacterial
- Usually unilateral
- Thick purulent discharge
- Reduced vision and risk of vision loss
Viral
- Bilateral (spreads from one to the other within a few days)
- Clear watery discharge with mucoid component
- Normal vision
What is the most common cause of viral conjunctivitis?
Adenoviruses
What is the management of viral conjunctivitis? Adenovirus vs HSV
Adenovirus - supportive eg application of cold moist compresses, artificial tears
Herpes simplex - topical antivirals eg ganciclovir
Topical abx is suspected overlying bacterial infection
Which bacterial conjunctivitis require systemic treatment?
Neisseria gonorrhoeae
Chlamydia
When are conjunctival scrapings and culture needed in conjunctivitis?
Persistent
Newborn conjunctivitis
Gonococcal / chlamydia suspected
How is conjunctivitis caused by neisseria gonorrhoea managed?
IV or IM ceftriaxone plus PO azithroymycin with saline irrigation
+/- topical abx
What is the management of bacterial conjunctivitis?
Self limiting in 60%
Should resolve in 1-2 weeks
Topical abx eg chloramphenicol 0.5% drops or 4/6hrs or fusidic acid can reduce duration of symptoms
What is the management of allergic conjunctivitis?
Antihistamine drops eg emedastine or olopatadine
Others eg cold compress, artificial tears
What can foreign bodies in the eye cause?
Chemosis - swelling of conjunctivia Subconjunctival bleeds Irregular pupils Iris prolapse Hyphaemia - haemorrhage into anterior chamber of eye Vitreous haemorrhage Retinal tears
What should be done if a high velocity FB is suspected in the eye?
Orbital US
Pick up rate is 90% compared to 40% for x rays
What is a closed globe contusion?
Occurs in the absence of a full thickness ocular wall laceration
Eg blunt trauma
What is an open globe injury?
Full thickness perforation or laceration of the ocular globe
Eg sharp or high velocity blunt objects
What is endophthalmitis?
Inflammation of the tissues or fluid inside the eye
Esp occurs following retained intraocular FB
What is a a blowout fracture?
Orbital contents are typically forced through a fractured orbital floor
eg high velocity blunt trauma to the globe and upper eyelid from punch / tennis ball
How may an ocular chemical burn present?
Intense pain Visual impairment Blepharospasm - involuntary eyelid closure Erythematous conjunctiva Photophobia
What is the management of an ocular chemical burn?
Immediate and thorough irigation with copious sterile saline or cold tap water
Use plastic scleral lens (Morgan lens) until pH normalises for acidic agents or 2-3 hours for alkaline agents
Abx eye drops eg tetracycline
Topical steroids eg prednisolone acetate 1%
What can cause sudden painless loss of vision?
GCA Optic neuritis Central retinal vein occlusion Central retinal artery occlusion Vitreous haemorrhage
How does GCA present?
New onset headache Malaise Jaw claudication Tender scalp and temporal arteries Neck pain Monocular vision loss
What is GCA associated with?
Polymyalgia rheumatica
What tests should be done for GCA?
ESR (>47)
CRP (>2.5)
- Preferably before steroids
Temporal artery biopsy within 1 week of starting prednisolone
What is the management of GCA?
Prednisolone 60mg/24hr PO
Tailor off steroids as ESR and symptoms settle, may take :1yr
20% left with partial / complete visual loss
How does optic neuritis present?
Unilateral loss of acuity over hrs-days
Colour vision affected - dyschromatopsia (red appears less red)
Eye movements hurt
What is optic neuritis associated with?
MS
45-80% will develop in 15yrs
What is the management of optic neuritis?
High dose methylprednisolone for 72hrs (1000mg/24hr IV)
then prednisolone 1mg/kg/d po for 11 days
What is more common - retinal vein occlusion or retinal artery occlusion?
Retinal vein occlusion
Structural changes in the eye occur with DM causing what two conditions?
Glaucoma
Cataracts
How can DM cause glaucoma?
DM causes ocular ischaemia, which can cause new blood vessel forming on the iris (rubeosis), and if these block the drainage of aqueous fluid, glaucoma can occur
What is the structural changes does DM cause in the eye?
Microvascular occlusion causes retinal ischaemia leading to arteriovenous shunts and neovascularisation
Leakage results in intraretinal haemorrhages and localised or diffuse oedema.
What are the two types of diabetic retinopathy?
Non-proliferative retinopathy
Proliferative retinopathy
How is non-proliferative diabetic retinopathy classified?
Mild
Moderate
Severe
= Depending on the degree of ischaemia
What signs can be seen in non-proliferative diabetic retinopathy?
Microaneurysms = dots Haemorrhages = flames / blots Hard exudates = yellow patches Engorged tortuous veins Ischaemic nerve fibres = cotton wool spots Large blot haemorrhages
What are signs of significant ischaemia in DR?
Engorged tortuous veins
Cotton wool spots
Large blot haemorrhages
How does non-proliferative diabetic retinopathy progress to proliferative diabetic retinopathy?
Fine new vessels appear on the optic disc and retina
Can cause vitreous haemorrhage
What is maculopathy?
Leakage from the vessels close to the macula cause oedema and can significantly threaten vision
What is the macula?
Central area of the retina
Who needs urgent referral in DR?
Severe NPDR
Proliferative retinopathy
Maculopathy
How is DR screened?
DM type 1 and 2 should have their eyes screened at the time of diagnosis and annually thereafter
What is the management of maculopathy and proliferative retinopathy?
Photocoagulation
Other than photocoagulation, what can be used to treat macular oedema?
Intravitreal triamcinolone
Anti-VEGF drugs
When is a haemorrhage a flame and when is it a blot?
Rupture of microaneurysms at the nerve fibre level = flame shaped haemorrhages
When deep in the retina = blot haemorrhages form
What is hyperopia vs myopia?
Hyperopia (long sighted) = an image of a distant object becomes focused behind the retina, making objects up close appear out of focus
Myopia (short sighted) = an image of a distant object becomes focused in front of the retina, making distant objects appear out of focus
In those with DR, what happens to their refractive index? What does this mean in terms of management?
At presentation - the lens may have a higher refractive index producing relative myopia
On treatment - the refractive index reduces and vision is more hyperopic
Do not correct refractive errors until diabetes is controlled
What other nerves are affected in DR?
Typically III and IV
Why may the pupil be spared in diabetic third nerve palsy?
Fibres to the pupil run peripherally in the nerve, receiving their blood supply from the pial vessels
What are Argyll Robertson pupils?
Bilateral small pupils that reduce in size on a near object (accommodate) but do not constrict when exposed to bright light (unreactive)
‘Prostitues pupil’ - accommodates but does not react
Result of bilateral damage to the pretectal nuclei in the brainstem
What causes Argyll Robertson pupils?
Non specific
Late stage syphilis
Diabetes
What happens in arteriopathic retinopathy?
Arteriovenous nipping - arteries nip veins where they cross (they share the same connective tissue sheath)
What happens in hypertensive retinopathy?
Damage from arterioslcerotic and HTN related processes
Arteriovenous nipping and arteriolar vasconstriction and leakage
What are the stages of hypertensive retinopathy?
Grades I - IV
Keith-Wagener-Barker system
What are grades I-IV of hypertensive retinopathy?
I - mild generalised retinal arteriolar narrowing or sclerosis
II - definite focal narrowing, AV nipping
III - cotton wool exudates, hard exudates, retinal haemorrhage, retinal oedema, macular star formation
IV - papilledema (optic disc swelling), optic atrophy
When does hypertensive retinopathy usually become symptomatic?
III and IV
Name two types of squint
Convergent squint (esotropia) Divergent squint (exotropia)
Which type of squint is more common? What causes it?
Esotropia - either no cause or can be due to hypermetropia
How are squints investigated?
Corneal reflection
Cover test
Describe a corneal reflection test
Reflection from a bright light falls centrally and symmetrically if no squint
Describe a cover test
Movement of the uncovered eye to take up fixation as the other eye is covered demonstrates a manifest squint
A latent squint is revealed by movement of the covered eye as the cover is removed
What is a paralytic vs a non paralytic squint?
Paralytic (or concomitant) squint is when the squint occurs in all directions of gaze, double vision does not normally occur
Non-paralytic is not constant, occurs when child is tired
Describe a 3rd nerve palsy
Down and out
Ptosis
Proptosis (decreased recti tone)
Fixed pupil dilatation
Describe a 4th nerve palsy
Up and adducted eye
Diplopia
Head may hold head tilted
Cannot look down and in (superior oblique paralysed)
Describe a 6th nerve palsy
Eye is medially deviated and cannot move laterally from midline - LR paralysed
Diplopia
What is the management of a swuint?
Glasses for refractive errors
Eye patches
Operation eg resection and recession of rectus muscles to realign
Botulinum injections
