Ophthalmology Flashcards
Causes of papilloedema
space-occupying lesion: neoplastic, vascular
malignant hypertension
idiopathic intracranial hypertension
hydrocephalus
hypercapnia
Rare causes include
hypoparathyroidism and hypocalcaemia
vitamin A toxicity
What is relative afferent pupillary
Marcus-Gunn pupil,
What causes
defect is when the affected and normal eye appears to dilate when light is shone on the affected eye
Causes
retina: detachment
optic nerve: optic neuritis e.g. multiple sclerosis
What causes:
dilated pupil
unilateral in 80% of cases
once the pupil has constricted it remains small for an abnormally long time
slowly reactive to accommodation but very poorly (if at all) to light
Holmes-Adie pupil
causes of Tunnel vision
is the concentric diminution of the visual fields
- papilloedema
- glaucoma
- retinitis pigmentosa
- choroidoretinitis
- optic atrophy secondary to tabes dorsalis
- hysteria
What causes on fundoscopy as irregular dark red streaks radiating from the optic nerve head
Angioid retinal streaks -degeneration, calcification and breaks in Bruch’s membrane .
Causes
pseudoxanthoma elasticum
Ehler-Danlos syndrome
Paget’s disease
sickle-cell anaemia
acromegaly
Drugs which may precipitate acute glaucoma
include anticholinergics and tricyclic antidepressants
What can Mydriatic drops cause .
acute angle closure glaucoma
What is the main difference in Open& closed angle glaucoma
peripheral iris is covering the trabecular meshwork= slowing or halting drainage of aqueous humour from the anterior chamber of the eye.
Open in it is impaired
Closed it c ompletely shut off
Risk factor for open angle Glaucoma
OPEN ANGLE
Risk factors:
Age esp > 80 years
genetics
Afro Caribbean ethnicity
myopia
hypertension
diabetes mellitus
corticosteroids
2ndary caused of open angle glaucoma
2ndar: blocked by cells of retina elements from detachment ,
WBC(uvitis) or
RBC (vitreous haemorrhage
Sx of Open angle Glaucoma
Progressive peripheral to central vision less
peripheral visual field loss - nasal scotomas progressing to ‘tunnel vision’
decreased visual acuity
optic disc cupping
Fundoscopy in open angle glaucoma
- Optic disc cupping - cup-to-disc ratio >0.7 (normal = 0.4-0.7), occurs as loss of disc substance makes optic cup widen and deepen
- Optic disc pallor - indicating optic atrophy
- Bayonetting of vessels - vessels have breaks as they disappear into the deep cup and re-appear at the base
- Additional features - Cup notching (usually inferior where vessels enter disc), Disc haemorrhages
IX glaucoma (4)
-
automated perimetry to assess visual field
slit lamp examination with pupil dilatation to assess optic nerve and fundus for a baseline - **applanation tonometry **to measure IOP
3.central corneal thickness measurement
- gonioscopy to assess peripheral anterior chamber configuration and depth
Assess risk of future visual impairment, using risk factors such as IOP, central corneal thickness (CCT), family history, life expectancy
Med that decrease production of aqueous humor ? (2)
- beta-adrenergic receptor antagonists - timolol,
- carbonic anhydrase inhibitors like acetazolamide
Meds that increase the outflow of aqueous humor through the uveoscleral pathway
or via trabecular meshwork
prostaglandin analogs like bimatoprost and latanoprost
trabecular meshworkas cholinomimetics like pilocarpine and carbachol,
Medications that Reduces aqueous production and increases outflow
when should they not be used
**Sympathomimetics ** brimonidine, an alpha2-adrenoceptor agonist)
Avoid if taking MAOI or tricyclic antidepressants
SE of Prostaglandin analogues (e.g. latanoprost)
Adverse effects include brown pigmentation of the iris, increased eyelash length
Who should Bblker be not given
Should be avoided in asthmatics and patients with heart block
SE: Carbonic anhydrase inhibitors (e.g. Dorzolamide)
Systemic absorption may cause sulphonamide-like reactions
SE Miotics (e.g. pilocarpine, a muscarinic receptor agonist)
Adverse effects included a constricted pupil, headache and blurred vision
Sx of closed angle glaucoma
Made worse by
visula sx
pupil
Cornea
- severe pain: may be ocular or headache
2.decreased visual acuity
- Sx worse w/ mydriasis (e.g. watching TV in a dark room)
- hard, red-eye
- haloes around lights
- semi-dilated non-reacting pupil
7.corneal oedema results in dull or hazy cornea
- systemic upset may be n/v,abdominal pain
Management of acute glaucoma
Combination of drops
IV acetazolamide
reduces aqueous secretions
Definitive management
laser peripheral iridotomy
creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle
2dary cause of closed-angle glaucoma
muscarinic blockers -atropine
=mydriasis, or pupil dilation, thus reducing aqueous humor outflow.
Lens need in myopia
ConCAVE
nearsited
Infectious congenital cataract causes
TORCH,
Toxoplasma,
Other infectious agents, usually syphilis; Rubella; Cytomegalovirus, and Herpes simplex virus
Genetic conditions ass w/ cataracts
trisomies 13, 18 and 21, Marfan syndrome,
Alport syndrome,
Refsum disease,
myotonic dystrophy, neurofibromatosis type 2,
and inborn errors of metabolism like galactosemia.
Risk factors for cataracts
age>60,
smoking,
excessive alcohol use, eye trauma and infections, exposure to UV light, prolonged glucocorticoids,
DM=osmotic cellular injury.
conjunctivitis last for wks with preauricular lymphadenopathy
Chlamydial
Chemosis (swelling of tissue lining eyelids and surface of the eye , conjunctiva)
profuse discharge
corneal ulceration
Gonococcal
Dendritic ulcer
HSV
vesicular rash around the eye, which may
with
Hutchinson’s sign: rash on the tip or side of the nose. Indicates nasociliary involvement
Harpies zoster
Hutchinson’s sign: strong risk factor for ocular involvement
Most common cause of viral conjunctivitis
Adenovirus
Difference between stye and chalazion
Conjunctivitis sign ass with gonococall infection
Sx uveitis
Causes of uveitis
What causes retinitis
HLA associated with graves
Difference btwn orbital cellulitis and periorbital cellulitis
Difference btwn orbital cellulitis and periorbital cellulitis
