Ophthalmology Overview - Vision Loss Flashcards
What is Sudden vision loss almost always caused by?
Almost always vascular except for retinal detachment, acute angle closure glaucoma and optic neuritis.
SUDDEN VISION LOSS
What is Branch/Central Retinal Vein Occlusion?
What are the 4 types of Retinal vessel occlusion?
What is the aetiology of Retinal vein occlusion?
- What does the visual morbidity usually arise from? (2)
- Treatment? (6)
Visual morbidity from:
1. Macular edema
2. Neovascularisation
Treatment
1. Observation.
2. Watch for neovascularisation in ischemic CRVO (“100-day glaucoma”).
3. Anti-VEGF injections for macular edema (the new gold standard).
4. Panretinal photocoagulation (PRP) for neovascularisation.
5. Laser chorioretinal anastomosis (vascular bypass).
6. Address vascular risk factors (HTN, DM, lipids, smoking, obesity).
Aetiology of Retinal artery occlusion?
What is this?
Acute central retinal artery occlusion
Narrow retinal arteries with box-carring of the retinal vessels (black dashed outline) and a pale retina indicating nerve fiber layer edema are visible. The fovea centralis appears red (cherry-red spot; blue overlay) due to the transparency of this part of the retina lacking nerve fibres, causing the well-vascularized choroid to shine through. Additionally, at the temporal superior arcade an embolus is present (arrow-head).
This is the classical finding of acute central retinal artery occlusion.
Blue circle: Optic disc
What is this?
Acute central retinal artery occlusion
The fovea centralis looks dark red (cherry-red spot; green overlay) due to the transparency of this part of the retina lacking nerve fibres, causing the well-vascularized choroid to shine through. The surrounding retina is pale and opacified, indicating ischemic edema. Narrow retinal arterioles with box-carring (examples indicated by arrowheads) are also visible.
These findings are typical of acute central retinal artery occlusion.
What is this?
Central retinal vein occlusion
Flame-shaped retinal hemorrhage is visible in all four quadrants (example indicated by green outline). The tortuous veins (green arrows) are markedly dilated and there is papilledema with loss of sharp demarcation of the optic disc (green overlay).
These findings are typical for a central retinal vein occlusion.
What is this?
Branch retinal vein occlusion
Flame-shaped retinal hemorrhages (examples marked by blue overlay) and cotton-wool spots (examples marked by arrowheads) that appear as bright, non-sharply demarcated lesions, are visible in the superior retinal hemisphere. The superior margin of the optic disc appears blurry (blurry margin of the disc marked by dashed blue line, sharply demarcated margin marked by blue line).
These findings are typical of a branch retinal vein occlusion (BRVO), in this case, hemispheric vein occlusion.
Blue circle: Optic disc
M: Macula
Branch/Central Retinal Artery Occlusion - Treatment? (5)
Treatment (within first 24 hours)
1. Breathe into paperbag (CO2 causes vasodilation)
2. Lower IOP: IV Diamox 500mg, Ocular massage, Anterior chamber paracentesis
3. Hyperbaric oxygen
4. Embolectomy
5. Address vascular risk factors (RAO represents a stroke affecting the eye). Always consider GCA in a patient 50+ who presents with a CRAO.
List & Explain 2 complications of retinal vessel occlusion?
What is Amaurosis fugax?
- Definition?
- Cause?
- Treatment?
- Complications?
SUDDEN VISION LOSS - What is Retinal Detachment?
Retinal detachment refers to the detachment of the inner layer of the retina (neurosensory retina) from the retinal pigment epithelium.
What are the 2 Types of retinal detachment and their mechanisms?
- The most frequent causes of retinal detachment are tears or holes in the retina (rhegmatogenous retinal detachment), risk factors for which include myopia, previous intraocular surgery, trauma, and/or posterior vitreous detachment.
- Less commonly, retinal detachment occurs without any retinal tears (non-rhegmatogenous retinal detachment).
- Non-rhegmatogenous retinal detachment is most often the result of vitreoretinal bands (e.g., proliferative diabetic retinopathy), subretinal/ intraretinal tumors (e.g., choroidal melanoma), or a number of systemic and ocular causes that result in subretinal fluid accumulation.
What is the Pathophysiology of Retinal Detachment?
Clinical Features?
Pathophysiology of Retinal Detachment
1. Detachment of the neurosensory retina, which contains the photoreceptor layer, from the retinal pigment epithelium.
2. Disturbed metabolism of the photoreceptor layer leads to loss of retinal function (i.e., vision impairment)
3. Separation of the retina from the choroid for more than 12 hours leads to retinal ischemia and retinal degeneration.
Retinal Detachment - Clinical Findings on Opthalmoscopy?
Retinal detachment - Treatment?
Non-rhegmatogenous retinal detachment
1. Tractional retinal detachment: Vitrectomy followed by internal tamponade and laser photocoagulation/cryoretinopexy.
2. Exudative (serous) retinal detachment:
- Due to sub-retinal fluid accumulation: spontaneous reabsorption of fluid; no treatment is required
- Due to tumors: enucleation
SUDDEN VISION LOSS - What is Vitreous hemorrhage?
- Definition?
- Aetiology?
- Clinical Features?
- Diagnostics?
Vitreous Haemorrhage - Clinical features
1. Sudden onset of symptoms: usually unilateral and painless
2. Floaters and/or visual loss: typically worse after sleep
Vitreous Haemorrhage - Diagnostics: Slit lamp examination
1. Blood between the posterior vitreous base and internal limiting membrane
2. Can determine the source of vitreous hemorrhage (e.g., retinal neovascularization)
3. Ocular B-scan ultrasonography if blood completely obscures the posterior segment of the eye
Vitreous hemorrhage - Treatment?
What is Age-related macular degeneration?
- 5 Risk Factors?
Risk factors
Risk Factors
1. Advanced age
2. Family history and genetic predisposition
3. Cardiovascular disease
4. Smoking
5. Obesity
What is the Pathophysiology of Age-related macular degeneration (AMD)?
Clinical Features of age-related macular degeneration?
- Fundoscopic findings?
-
Painless central or pericentral visual impairment → reduced visual acuity, difficulty adapting to changes in lighting
- Dry AMD: slow progressive visual impairment (usually over decades) and unilateral or bilateral onset
- Wet AMD: acute or insidious onset (over weeks to months) and usually manifests in one eye first - Metamorphopsia: type of visual distortion in which straight lines appear wavy, which can be tested for using an Amsler grid
- Scotoma (blind spot)
What investigations should you perform if wet AMD is suspected? What will you find?
What is Non-arteritic anterior ischemic optic neuropathy (NAION)?
Non-arteritic anterior ischemic optic neuropathy (NAION) refers to loss of blood flow to the optic nerve. In many cases, the patient notices significant loss of vision in one eye immediately upon waking up in the morning. The visual loss typically remains fairly stable, without getting markedly better or worse once it has occurred.
= This is a stroke affecting the optic nerve.
What is Arteritic Anterior Ischemic Optic Neuropathy (AAION)?
- Clinical Features?
Arteritic Anterior Ischemic Optic Neuropathy (AAION) is an acute, often painful optic neuropathy that occurs predominantly in elderly patients over age 50 but with increasing incidence each decade thereafter and can cause permanent loss of vision.
- Ischemia occurs at the head of the optic nerve in relation with structural crowding of the nerve fibers, impairing perfusion and leading to optic disc edema.
Arteritic Anterior Ischemic Optic Neuropathy (AAION)
- Treatment?
AAION: Treatment
- Urgent ESR & CRP.
- Do not delay PO steroids (mg/kg/day) or IV methylprednisolone.
- Temporal artery biopsy within 10 days (>3cm section because of skip lesions). - Rheumatology referral.
- Always consider GCA in any patient 50+ who presents with sudden LOV or diplopia.
How can you distinguish between AAION and NAION?
AAION
- Older.
- Female.
- Constitutional Sx.
- Worse presenting vision (usually <6/60).
- Pale swelling of disc.
- Elevated ESR/CRP.
What is Optic Neuritis?
- Definition?
- Aetiology?
- Clinical features?
Typical ON
- Age 20-50 usually female.
- Unilateral vision loss over hours/days.
- Retrobulbar pain worse on eye movement. - Reduced colour vision.
- RAPD.
- In retrobulbar neuritis, the optic disc looks normal (“the patient sees nothing and the doctor sees nothing”).
Optic Neuritis
- Diagnostics?
Optic Neuritis
- Treatment?
Optic Neuritis - Treatment
1. MRI to rule out multiple sclerosis (ON is often the first presentation of MS).
2. In typical ON, spontaneous improvement is the rule.
3. Consider IV Methylprednisolone followed by PO Prednisolone if quicker recovery is required eg. poor vision in other eye or severe pain.
4. Never use PO steroids alone as this increases the risk of recurrence.
5. Steroids do not affect final visual outcome but it may delay the onset of clinically definite MS if demyelinating lesions are present on MRI (Optic Neuritis Treatment Trial).
What is Gradual Vision Loss mostly caused by?
GRADUAL VISION LOSS
Mostly caused by age-related changes.
What is Corneal dystrophy?
- 4 Subtypes?
- Definition?
- Classification?
- Aetiology?
- Clinical Findings?
- Diagnostics?
- Treatment?
What is Cataracts?
- 5 associated disorders?
Universal malady with aging (but can be congenital). Other associations:
1. Trauma.
2. Long-term steroids.
3. Diabetes.
4. Irradiation.
5. Uveitis.
List 10 Causes of Acquired Cataracts?
List 6 Causes/Associated conditions of Congenital Cataracts?
How is Cataracts Classified?
Cataracts are generally classified according to etiology. Age-related cataracts can also be classified according to where they form in the lens (morphology) or how advanced they are.
Clinical Features of Acquired Cataracts?
5 Clinical features of congenital cataracts?
Congenital cataracts manifest differently than acquired cataracts:
1. Leukocoria
2. Strabismus
3. Nystagmus
4. Delay in motor skill development
5. Deprivation amblyopia
Cataracts - Diagnostic Findings?
- Visual Acuity?
- Fundoscopy?
- Slit lamp?
Cataracts - Treatment?
- 4 Indications for cataracts surgery?
- 3 Contraindications for cataracts surgery?
- 4 Surgical options?
- In most cases, definitive management of cataracts is not possible without surgery.
- No pharmacologic agents are available to treat cataracts.
Glaucoma - Treatment?
