Loss of Vision Flashcards
What part of the eye is affected in loss of vision?
Posterior segment
What are the key things to remember when taking history from of a patient with loss of vision?
- Unilateral/bilateral
- Onset: sudden/gradual (over what period of time)
- Type of visual loss: blurred/distorted/black
- Any associated symptoms (pain, redness, discharge)
What examinations should be carried out for a patient with loss of vision?
- Best corrected visual acuity - snellen chart
- Fundal examination - direct opthalmoscope & slit lamp and volk lens
What are ancilliary tests?
Ancillary, or point-of-care, testing is unique because it is not performed in a centralized location; for most laboratory tests, a blood or other body fluid specimen is collected from a patient and sent to the lab for testing - with point-of-care testing, healthcare professionals perform testing at the patient’s side
Give examples of ancilliary tests
Amsler chart Colour vision Visual field assessment Flurescein angiography Optical coherence tomography
What is the Amsler chart used to assess?
Patients asked to look at a grid
If the lines look wavy / distorted OR some lines are missing, indicates problem with the the macula
(Macular degeneration)
What is fluorescein angiography?
The yellow fluorescein dye is injected into the bloodstream
Done to highlight the blood vessels in the back of the eye so they can be photographed
What is optical coherence tomography?
Non-invasive imaging test that uses light waves (NOT RADIATION) to take cross sectional images of the patient’s retina.
Layers within the retina and retinal thickness can be assessed
Name some vascular causes of sudden complete loss of vision
Central retinal artery occlusion
Central retinal vein occlusion
Anterior ischaemic optic neuropathy (sudden loss of vision due to an interruption of blood flow to the front (anterior) of the optic nerve (optic nerve head)
What is the management for central retinal artery occlusion?
Identify & treat risk factors e.g. embolus (eg, due to atherosclerosis or endocarditis), thrombosis, or giant cell arteritis
can also include vasodilators, fibrinolytic therapy laser photodisruption of embolus or IV steroids in the case of giant cell arteritis)
What is the management for central retinal vein occlusion?
Identify & treat risk factors e.g. caused due to a blood clot which can result from high blood pressure, high cholesterol, glaucoma, diabetes, smoking, certain rare blood disorders
OR
intravitreal antivegf
What are the 2 types of anterior ischaemic optic neuropathy?
- Arteritic: giant cell arteritis
- Non-arteritic
The former is an inflammatory disease of medium/large sized blood vessels and has more serious consequences for vision.
The latter is more common but less severe.
What are the symptoms of giant cell arteritis?
- loss of vision
- headache
- loss of appetite
- scalp tenderness
- pain on chewing
What are the signs of giant cell arteritis?
- tenderness of superficial temporal arteries
- raised inflammatory markers
What is the management for giant cell arteritis?
medical emergency! high dose systemic steroids
What is characteristic of non-arteritic AION?
Painless
What is the management for non-arteritic AION?
Identify & treat risk factors (these again can include diabetes, hypertension and other cardiovascular diseases)
Name some causes of a gradual loss of vision
Cataract
Glaucoma
Age related macular degeneration
Diabetic retinopathy
What is a cataract?
Gradual opacification of the lens; proteins in lens clump together as we age and this can cloud the lens
What are the symptoms of cataracts?
- loss of vision
- cloudy vision
- colours more faded
- dazzle/glare
- multiple/double visions in one eye
What is the investigation and management for cataracts?
To investigate - visual acuity test, slit lamp examination, dilated eye exam, tonometry to measure pressure
Treatment is surgery (phacoemulsification with intraocular lens implant)
What is glaucoma?
Optic neuropathy with typical optic nerve damage and associated visual field changes usually associated with raised intraocular pressure
What are the classifications of glaucoma?
- open or closed angle
- chronic or acute
What are the symptoms of glaucoma?
- asymptomatic
- gradual loss of peripheral field of vision
What are the signs of chronic glaucoma?
- raised intraocular pressure
- visual field defects
- optic disc damage
What is the management for chronic glaucoma?
topical treatment e.g. dorzolamide and brinzolamid
surgery (trabeculectomy)
What are the symptoms of age related macular degeneration (AMD)?
progressive loss of central vision
distorsion
What are the signs of AMD?
- distorsion on amsler chart
- drusen
- pigment epithelial changes
What are the types of AMD?
Dry (90%)
Wet (neovascular) (10%)
What is found in dry AMD and what is the management for it?
drusen (yellow deposits under the retina)
atrophy (management = low vision aids; registration)
What is found in wet AMD?
choroidal new vessels (creation of new vessels in the choroid layer of the eye)
What are the investigations of wet AMD?
OCT (optical coherence tomography)
Fluorescein angiography
What is the management for dry AMD?
Intravitreal anti vegf
Low vision aids
Registration
What is the commonest cause of visual impairment in working age population?
Diabetic retinopathy
What are the signs of diabetic retinopathy?
- microaneursyms
- retinal haemhorrhages and exudates
- neovascularisation (disc/retina)
What are the investigations for diabetic retinopathy?
Fluorescein angiography
OCT (showing diabetic macular oedema)
What is the management for diabetic retinopathy?
Intravitreal anti vegf
Laser - panretinal photocoagulation
Low vision aids
Registration
What are some symptoms and signs of central retinal artery occlusion?
Sudden, painless loss of vision occurring over seconds
Visual acuity reduced
Direct pupillary reflex absent
Fundal examination = inc milky white retina, cherry red spot, marked narrowing of retinal arteries, atrophic changes
Fluorescein angiography = delay of arterial filling, masking of choroidal vasculature due to retinal oedema
What is intravitreal vegf?
Intravitreal (into the vitreous part of eye[posterior]) anti-Vascular endothelial growth factor - these treatments are given by an injection into the eye and reduce the growth of new blood vessels and the oedema (swelling) they may cause
(can also treat with steroid eye implants or laser photo-coagulation)
