Assessment of Visual Failure - Murtag Flashcards
Blindness by WHO
less than 3/60
Minimum vision for driving in Australia
6/12
Key points for Sudden vision failure
Transient occlusion of retinal artery (amaurosis) and migraine
Flashing lights
retinal detachment
Floaters and blobs
Aging Pigment in viterous humor Vitreous hemorrhage Posteroir viterous detachment Choroiditis
Acute onset of floaters
posterior vitreous detachment
Causes of central vision impairment
defective retinal
- Refractive error
- opacity in occular media
- macular/optic nerve dysfunction
Causes of peripheral vision impairment
extramacular disease
defects in visual pathway
Oculotoxic drugs
TB
ethambutol
quinine, chloroquinine
Family History important in vision loss
DM Migraines Lebers heriditary optic atrophy Tay-Sach disease Retinitis pigmentosa
Causes of coloured halos around lights
Glaucoma
Cataracts
Causes of worsening vision in night or around dim lights
retinitis pigmentosa
hysteria
syphilitic retinitis
Causes of headache with vision changes
Migraine
Temporal arteritis
Benign intracranial HT
Causes of central scotomata (blind spot)
Macular Disease
Optic Neuritis
Pain on occular movement
Retrobulbar neuritis
Distortion Micropsia (smaller), macrospsia (larger)
Macular degeneration
Disorders to exclude
- DM
- Gaint cell (temporal) arteritis
- hypopiturism (pituatary adenoma)
- Cerebrovascular ischemia/carotid artery stenosis
- MS
- Cardiac disease (arrhythmias and SBE - emboli
- Anemia (severe can cause retinal hemorrhages and exudate)
- Marfan’s syndrome - subluxated lens
- Melanoma of choroid
Examinations of vision failiure
- Visual Acuity - Snellen Chart, pinhole testing ?refractive
- Pupil reaction - afferent (sensory) responses to light ?temporal arteritis, ?central retinal artery occlusion, ?optic neuritis
- Confrontation field
- Colour vision
- Amslers grid
- Fundus exam with dilated pupil - note red reflex (?cataracts, malignant melanoma), retina, macula, nerves
- Tonometry ?glaucoma
Investigation
- Blood test - Full blood (?Anemia, ?lead poisoning ?leukemia)
- ESR - ?Temporal cell arteritis
- Blood sugar ?DM - Temporal artery biopsy ?temporal cell arteritis
- CT/MRI ?CVA, ?optic nerve lesion, ?space occuping lesions
- Formal perimetry and Bjerrum screen ?glaucoma
- Fluroscein angiography ?retinal vascular obstruction, ?DM retinopathy
- Visual evoked potential ?demyelinating disorders
- Carotid doppler US
Types of Macular degeration
Dry - build up of drusen in retinal pigment epithelium leading to loss of retinal pigment epithelium
Wet - choroidal neovascularisation
Urgent consideration for vision loss
- Acute angle closure glaucoma - severe periorbital pain, with abdo symptoms
- Retinal detachment - visual field loss, peripheral vision loss, flashes and floaters, surgery immediately
- Retinal vascular occlusion - similar to detachment
- Corneal ulcer - vision loss w/ painful red eye
- Pituitary apoplexy - acute vision loss with headache and ocular motility disorder
- Gaint cell artheritis - monoocular, jaw caudication and headache, scalp tenderness, weight loss
- Cerebrovascular accident
- Uveitis - conjuctivitis
- Post-operative endophthalmitis - painful red eye after cataract surgery
- Trauma
Sudden monoocular vision loss in older patients
Gaint cell arteritis
Sudden monoccular vision loss in younger adults
Embolic event - from coagulation disorders
DM patient with recent hyperglycemic event and now vision loss
refractory error due to lens swelling
Drugs causing colour changes to vision
digoxin = yellow
erectile dysfunction drug = blue
Corneal Ulcer
- Think for contact lens wearers
- Painful red eye with watery or mucoid disarge
- Exam = Fluorescien staining,
First test = gram stain for bacteria, corneal culture
Dry eye syndrome
-Intermittent visual blurring, may be worse in morning or evening, gritty sensation, light sensitivity without photophobia. relieved by artificial tear use.
Exam = normal, slit lamp may show occular surface irregularity
1st test = tear breakup time
Dry age related macular degeration
acute or chronic painless loss of vision or distortion of the central vision.
Exam = distorted central acuity with normal peripheral vision
1st test = fluorescein angiogram
refer to retinal specialist within 72 hours
Posterior Uveitis
painful onset of clouding, slowly, flashes and floaters, photophobia, pain on eye movement
Exam- tender red eye, +/- nodular lesion on sclera, cloudy/obstructed view of retina
1st test = FBC with differentials (inflammatory vs infective)
Cataracts
painless, progressive loss of vision
