Opthalmology Flashcards
Painful reduced vision in one eye with vomiting and halos around lights
Acute closed angle glaucoma
What is the treatment for acute closed angle glaucoma
i. acute
ii. defintive
Treatment:
ACUTE:
Timolol= a beta blocker, and
Apraclonidine= an alpha agonist,
both used to block production of aqueous humor and promote pupillary miosis.
Additionally, systemic carbonic anhydrase inhibitors, such as acetazolamide, can be used to prevent secretion of aqueous humor.
DEFINITIVE:
-Laser iridotomy to create an opening in the iris, allowing drainage of the posterior chamber and an increase in the anterior chamber angle.
Exacerbating symptoms for glaucoma
Glaucoma may be exacerbated by entrance into a dark room (e.g. movie theater) or reading in dim light where pupillary dilation is the normal response.
Gold standard diagnostic tool for glaucoma
Gonioscopy, performed by an ophthalmologist, is the gold standard for diagnosis of acute angle closure glaucoma.
What are the causes of loss of red reflex
The best-known causes of loss of the red reflex are cataracts
(opacification of the lens)
and
retinoblastoma (a rare form of cancer involving cells of
the retina in children).
Differentiate bacterial and viral conjunctivitis
Bacterial is unilteral, viral is bilateral
Bacterial is thick discharge, viral is watery
Bacterial is reduced vision, viral is normal
Bacterial cause includes STD so may have urethritis/bacterial discharge from vagina,
Viral may have fever and lypmphadenopathy
Painless visual imparment with glare and halos around lights?
Noticed eye has gone white
Cataracts.
Reduced red reflex and clouding of lens
Define cataracts
Opacification of the lens of the eye
Explain the aetiology / risk factors of cataracts
Majority idiopathic age related.
Secondary causes:
Local- previous eye trauma, uveitis, intraocular tumours
Systemic- diabetes, metabolic disorders, drugs (steroids), x-ray/UV radiation, Down’s syndrome, systemic disease
Congenital: CONGENITAL RUBELLA SYNDROME
Summarise the epidemiology of cataracts
35% of >65 year old people have visiaully impairing cataracts in at least one eye
Recognise the presenting symptoms of cataracts
Gradual onset PAINLESS loss of vision
Glare from bright lights
Vision may worsen in bright light (especially with central lens opacity)
Monocular diplopia/haloes around lights
Can read without glasses
Ambylopia or nystagmus in infants
Recognise the signs of cataracts on physical examination
Loss of red reflex
Hazy lens appearance
Reduced visual acuity
Identify appropriate investigations for cataracts and interpret the results
Biometry:
To assess appropriate intraocular lens implant.
Other unnecessary unless occurring at early age or associated with systemic disease
Define glaucoma
Optic neuropathy with typical field defect usually associated with ocular hypertension (intra-ocular pressure, IOP>21mmHg).
Damages optic nerve and can lead to blindness
Explain the aetiology / risk factors of glaucoma
What is the anterior vs posterior chamber of the eye. What is the vitreous chamber
See below for normal aqeous humor physiology
Blockage in the pathway through which aqeous humour is drained.
Anterior and posterior chamber are both parts of the anterior segment.
Anterior chamber: from cornea to iris.
Posterior chamber: from iris to lens
Vitreous chamber: from lens to back of eye.
Due to blocked drainage, the pressure within the fixed anterior chamber builds up, causing intraocular hypertension.
This high pressure affects all part of the eye, including the optic nerve (even though the high pressure is in the anterior chamber).
As optic nerve gets damaged, glaucoma leads to vision loss.
- OPEN ANGLE GLAUCOMA (most common)
- CLOSED ANGLE GLAUCOMA.
Summarise the epidemiology of glaucoma
Prevalence 1 % in over 40 years, 10 % in over 80 years (POAG). Third most common cause of blindness worldwide
Recognise the presenting symptoms of glaucoma
ACAG: Painful red eye, vomiting, impaired vision, haloes around lights.
POAG: Usually asymptomatic, peripheral visual field loss may be noticed.
See below for explanations
Recognise the signs of glaucoma on physical examination
Primary causes: acute closed angle glaucoma (ACAG), primary open angle glaucoma (POAG)
ACAG:
-Red eye, hazy cornea, loss of red reflex, fixed and dilated pupil, eye tender and hard on palpation, cupped optic disk, visual field defect (arcuate scotoma), moderately raised IOP, blurred vision
POAG:
-Optic disk may be cupped. Usually no signs.
Secondary causes:
-Trauma, uveitis, steroids, rebeosis iridis (diabetes, central retinal vein occlusion)
Congenital:
-Bupthalmos
Identify appropriate investigations for glaucoma and interpret the results
First thing, POAG is a diagnosis of exclusion. You must do the following things.
Firstly: Goldmann applanation tonometry (standard examination to measure ocular pressure, will be >30 in primary)
Gold standard: Gonioscopy to assess the angle
Perimetry: for arcuate scotoma (early) and tunnel vision (late)
What is the normal secretion and drainage of aqeous fluid
Aqeous humor secreted into posterior chamber from the ciliary epithelium. It then travels past the iris, into the anterior chamber, and is drained via the trabecular meshwork into the canal of schlemm, which then allows the fluid to drain into aqeous veins, part of the episcleral venous system.
What is the cause of open angle glaucoma
What is the history
The angle between cornea and iris is open.
The drainage system itself slowly becomes clogged, leading to gradual build up of pressure.
This causes the outer rim of the optic nerve to atrophy. As damage continues, eventually the centre of vision will be lost as well
History:
Peripheral loss of vision –> central vision loss
What is the cause of close angle glaucoma
What is the history
Angle between iris and cornea is too small, so the passage for aqeous humor is too small.
This is because the lens gets pushed against the iris, and the iris then is pushed towards the cornea, impairing the drainage angle
There is a rapid build up of pressure within the eye
Hx: Abrupt onset eye pain Redness Blurry vision Headaches Nausea Visual halos
Causes of abnormally large pupil
1) Third nerve palsy
2) Pharmacological
3) Acute glaucoma
4) Unilateral fixed dilated pupil (raised ICP and coning)
What is optic neuritis and what would the next investigation be
Optic neuritis refers to inflammation of the optic nerve caused by demyelination.
Diagnosis is usually clinical- unilatral deterioration in visual acuity and colour perception + PAIN on eye movement (see MS)
However, imaging may be required to exclude alternative causes of optic nerve dysfunction and also to assess the risk of future episodes of CNS demyelination.
Best investigation is MRI as it can show characteristic lesions of MS and demyelination
What is the treatment of optic nueritis
In optic neuritis, vision typically worsens over one or two weeks, and then recovers over approximately 6 weeks. However the final vision varies considerably between individuals, usually being proportional to the worst level of vision during the episode.
No treatment given routinely. Steroids speed up recovery but don’t impact final vision, so used occassionally if` someone has poor vision ij both eyes and would benefit from quicker recovery
Temporal lobe lesions cause what visual field problem
Temporal lobe lesions cause homonymous superior quadrantanopias on the opposite side. This is due to involvement of the inferior fibres of the optic radiation.
Parietal lobe lesions cause what visual field problem
Parietal lobe cause homonymous inferior quadrantanopias of the opposite side. This is due to involvement of the superior fibres of the optic radiation.
(Parietal affects Superior fibres leading to homonymous Inferior quadrantanopias….. P, S, I)
Treatment of diabetic retinopathy
Non-prolif:
- Laser treatment FOCAL photocoagulation
- Intravitreal anti-VEGF injection
Proliferative:
- PANRETINAL photocoagulation
- Vitrectomy in case of traction retinal detachment and vitreal haemorrhage
Macular oedema:
- VEGF inhib
- Focal photocoagulation
Cherry red spot?
The sign of a branch retinal artery occlusion is a small yellow or pale spot (the embolus) wedged in a branch retinal artery. These are usually seen incidentally, but should prompt the same cardiovascular workup as would occur after a transient ischaemic attack. (The ‘cherry red spot’ is seen into days or weeks after central retinal artery occlusion.)
3 clinical parameters characterising open angle glaucoma
1) Raised intraocular pressure
2) Increased cup to disc ratio
3) Visual field defects (perimetry)
Risk factors for progression of diabetic retinopathy
Lack of exercise
Not getting annual eye checks
Poor glycaemic control
Poor BP control
Pregnancy
Risk factors for acute angle closure
Age, hypermetropia (long sightedness)
Most common cause of the following, and the sign:
- Infective endopththalmitis
- Infective keratitis
Infective endophthalmitis is characterised by a hypopyon, and typically occurs days or weeks following intraocular surgery (for example for cataract) or intravitreal injections (for example of anti-VEGFs)
infective keratitis refers to corneal inflammation, and usually is infective. Most commonly this is due to herpes simplex (causing a dendritic ulcer), or less commonly bacteria
Treatment of acute angle closure glaucoma
IV acetazolamide to drop IOP
Prostaglandin and beta blockers
pilocarpine drops to cause miosis (constriction) which helps to unblock drainage anlge
Either that day or after several days, laser peripheral iridotomy is done to both eyes (as if the acute glaucoma attack occurred in one eye, the other eye is likely to be vulnerable to an attack in future)
Define uveitis
Inflammation of the iris and ciliary body (iritis or iridocyclitis)
Causes of anterior uveitis
Infection (HSV, herpes zoster, TB)
Manifestation of systemic inflammatory condition (juvenile chronic arthritis, HLA-B27-related spondyloarthropathy (ankylosing spond, reactive arthritis, IBD), sarcoidosis, bechets disease.
Rarely associated with tubulointerstitial nephrotis
What is sympathetic opthalmia
Inflammation of the contralateral eye weeks/months after penetrating injury (rare).
History of uveitis
Pain- ciliary spasm and inflammation, pain on accommodation
Photophobia, red eyes, blurred vision, lacrimation
Investigations for uveitis
Investigate for associated systemic conditions depending on associated symptoms: U&Es, spondyloarthritides (sacroiliac joint X-ray, HLA typing), sarcoidosis (CXR, serum calcium, serum ACE), syphilis serology.
What is seen on slit lamp with anterior uveitis
On slit lamp examination, one sees the characteristic “cells and flare” appearance.
Scleritis, when does pain occur
On movement
Orbital vs perioribital cellulitis
Orbital cellulitis
is an infection of the
soft tissues
of the orbit which extends posterior to the orbital septum.
Pre-septal (periorbital) cellulitis , which is a less serious condition is confined to the soft tissues anterior to the orbital septum.
What clinical features differentiate orbital nad peri orbital cellulitis
Proptosis
and
ophthalmoplegi
Which can if you suspect orbital cellulitis
A
CT scan
is necessary to evaluate the extent of involvement of the infection and any
abscess
formation or other complications that may indicate the need for surgical intervention
What is conjunctivitis
Conjunctivitis (pinkeye) is a very common inflammation of the conjunctiva (the mucus membrane that lines the inside of the eyelids and the sclera)
Cause of conjunctivitis
It is most commonly caused by viruses or bacteria but can also have noninfectious (e.g., allergic) causes
Clinical features of viral vs bacteria conjunctivitis
Bacterial:
- While bacterial conjunctivitis can present in only one eye, it is usually present in both eyes or will spread to the contralateral eye
- Thick purulent discharge (yellow, white or green)
- Reduced vision
- Extraocular signs of bacteria infection (urethritis)
Viral:
- The disease is almost always unilateral and monocular.
- Clear, watery discharge
- Conjunctival follicles (yellowish-white hyperplasia of lymphatic tissue)
- Fever, lymphadenopathy
What is the most common type of conjunctivitis
Viral
Causes of viral conjunctivitis
Adenoviruses (most common), herpes simplex virus (HSV), varicella-zoster virus (VZV),
(picornavirus, molluscum contagiosum, HIV (highly contagious), measles, zika)
Fever, pharyngitis, acute follicular conjunctivitis. There is tender preauricular lymphadenoopathy
Pharyngoconjunctival fever!
A type of viral conjunctivitis caused by adenovirus 3
Vesicular blepharitis (inflammation of eyelids) and dendritic epithelial keratitis of cornea and conjunctiva
HSV conjunctivitis
Subconjunctival and petechial hemorrhage, eyelid ecchymosis, increases lacrimation, unilateral pre-auricular lymohadenopathy
Epidemic keratoconjunctivitis
Investigations for viral conjunctivitis
Clinical diagnosis + history of upper respiratory infection, if present
Conjunctival smear and cultures (or viral isolation) if symptoms are recurrent/chronic
Most common causes of bacterial conjunctivitis
Staph aureus (most common in adults)
Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas, Haemophilus, and Moraxella catarrhalis
The others are more common in kids
Diagnosis of bacteria conjunctivitis?
Clinical diagnosis
Conjunctival scrapings and culture (or PCR) required if persistent or severe disease (i.e., multiple or large corneal lesions), if the diagnosis is uncertain, and in newborn conjunctivitis
Young person with hyperacute conjunctivitis with marked eye swelling and profuse purulent discharge adn periauricular lymphadenopathy
Neisserial conjunctivitis
Cause of neisserial conjunctivitis
Pathogen: Neisseria gonorrhoeae
Highly infectious:
Young, sexually active adults: direct contact to contaminated secretions (e.g., from the genitalia to the hand to the eye)
Newborns: perinatally
T/F N gonorrhoea infection is an ocular emergency
T!
Can lead to keratitis, perforation, and blindess without prompt treatment!
Most common cause of blindness worldwide
Trachoma
Cause of trachoma
=GRANULAR CONJUNCTIVITIS
Infection with Chlamydia trachomatis type A-C
Route of infection: direct (human-to-human contact with eyes or nose) or indirect (flies or towels) contact
Stages of trachoma
Trachomatous iflammation of upper eyelid (follicular)
Trachomatous scarring
Entropion (turning in of eyelid)
Trachomatous trichiasis (eyelashes turn in)
Corneal opacity
Most common cause of viral conjunctivitis in newborns
HSV 2
