Ophthalmology Problems Flashcards
(24 cards)
Brain
Compensates for loss of central vision by providing peripheries
Basics of anatomy
External
Cornea
Iris
Lens
Ciliary body
Vitreous
Retina
Optic nerve
Brow Lids and lashes Tear ducts and lacrimal glands Orbit Nerves and blood supply
Extra-Ocular muscles
Obliques allow for
Superior rectus
Inferior rectus
Lateral rectus
Medial rectus
Superior oblique
Inferior oblique
Torsion and rotation
What do you see on back of eye
Macula
Centre of vision - dark spot q
Optic nerve
Retinal vessels
Retina
Eye and the brain
Eye is camera, brain is processor
Optic nerve is nerve of sight
Retina converts light into electrical impulses that travel down the optic nerve to the brain for processing
Problem in brain can affect visual processing and also give rise to visual disturbances
Visual pathway
2 pathways
Mechanism
Lesion in any part of visual pathway gives particular visual field defect
Nasal and temporal
Nasal field of vision hits temporal retina
Temporal visual field hits nasal retina
Superior falls on inferior retina
Crossover (decussation) at optic chasm therefore R side represented on the L side
Incidents which may cause loss of fields of vision
Stroke - cerebral artery - both fields on one side
Pituitary tumour - bitemporal hemianopia
Causes of visual disturbance
Pathological processes affecting eye or affecting brain structures involved in visual processing
Symptoms of visual disturbance
Loss of vision Flashing lights and floaters Droopy lids Visual field defects - central, peripheral, both Headaches Pupil size inequalities Diplopia
Causes of visual disturbance
Eyes
Brain causes
Systemic
Cataract Macular degeneration Glaucoma Retinal detachment Eye infections
Stroke
Inflammations
Migraine
Papilloedema - optic nerve swelling
Diabetes and diabetic retinopathy
Vessel occlusions and atherosclerosis
Giant cell arteritis
Accelerated hypertension
Red eye causes
Conjunctivitis - allergic, bacterial or viral
Burst blood vessel - subconjunctival haemorrhage
Viral e.g adenovirus
Vision normal
Watery means viral
Purulent discharge suggests bacterial
Treatment involves lubricant drops and antibiotic drops
Ulcer or abrasion?
Corneal abrasion
Painful
Due to trauma
Heals within 2-3 days
Ulcer
Very painful
Related to contact lens wear
Urgent referral to ophthalmologist
Subconjunctival haemorrhage
Can look worrying Spontaneous or traumatic on anticoagulants? Clotting problems? Check BP Two weeks to resolve
Anterior uveitis
Uvea
Iris, ciliary body and choroid iris sticks to anterior surface of lens Inflammation within front of the eye Pain light sensitivity Vision can be decreased Irregular pupil Can be linked to ankylosing spondylitis Needs referral Can get collection of pus at base of eye
Angle closure glaucoma
Causes
Fixed mid eye pupil
Halo in light
Corneal oedema
Angle between iris and cornea (fluid drainage through pupil behind cornea)
High pressure in the eye, must be lowered before optic nerve undergoes irreversible damage –> BLINDNESS
Often older
Very painful red eye with decreased vision
Accompanied by nausea and vomiting
Need urgent referral to ophthalmology
Scleritis
Inflammation of sclera - tough outer coat of eye
Normal vision
Deep red inflammation, violet or bluish line
Intense pain, wakes patient from sleep
Requires referral
Vision loss - causes
Cataracts
Corneal ulcer –> scar
Retinal issues
Bleed into vitreous humour
Cataract
Clouding opacity of lens
Due to ageing
Occurs earlier in diabetic, trauma and steroids
Results in gradual loss of vision
Macular degeneration
Two types
Age related change at macula which is central part of vision
Wet and Dry
Can be dry with deposits called DRUSEN found in macular region
Can be ‘wet’ (neovascular) with new blood vessel growth at the macular area and leakage of fluid
Patients complain of loss of central vision or distortion
Visual loss - Retinal detachment
More susceptible with thinner retina
Patients see a shadow in peripheral vision typically preceded by flashing lights and floaters
Retina becomes detached from wall of the eye - jelly becomes more liquid with age and fluid can get beneath tear and lift retina off
Can progress to permanent irreversible vision loss
Visual loss - CRAO
Central retinal artery occlusion
Central retinal artery is blocked by an embolus
Prognosis is poor as they are end vessels
Sudden irreversible loss vision
Parasenthesis - reduction of pressure
Commonly caused by embolus due to atherosclerosis
Rarely associated with giant cell arteritis (consider if headache is symptom)
URGENT REFERRAL
Visual loss - diabetes
Associated with
Treatment
Retinopathy causes vision loss due to microvascular changes e.g vessels become leaky and
- retinal oedema - significant if macula affected
- vessels can shut down –> retinal ischaemia and new blood vessel growth –> bleed and cause vision loss
Worsening diabetic eye disease associated with poor diabetes control
Healthy tissue is lasered to prevent future damage
Visual loss - glaucoma - open angle chronic glaucoma
Painless with elevated eye pressure over a prolonged period
Patients asymptomatic until late stage - gradual field loss
Optic nerve undergoes progressive nerve damage resulting in cupped appearance
Visual problems and headache
Migraines
Giant cell arteritis
Papilloedema
Zig-zag lights, field defects, aura
severe headache, scalp pain, jaw pain , can cause strokes and bilateral blindness
raised intracranial pressure can cause optic nerve swelling and visual disturbance
