Opthalmology - Vision Loss, Disorders of ocular media and posterior eye Flashcards
Ddx transient vision loss
Differentiating features
Retinal TIA
**Retinal Migraine **
**Papilledema **
Ddx ocular media disorders that cause acute vision loss
- Keratitis
- Acute glaucoma/ corneal edema
- Anterior uveitis
- Hyphema or trauma
- Acute lens changes/ lens dislocation/ lens opacity
- Vitreous hemorrhage
Hyphaema
Features
- Hyphaema refers to blood in anterior chamber
- May result from blunt trauma or spontaneously in ds characterized by neovascularization (eg. DM)
- Slit lamp examination shows blood in anterior chamber ± ↑IOP
Acute lens changes
Causes
- Due to changes in size, clarity or positioning of lens resulting in alteration of focus of light onto the retina
- Lens dislocation can occur in trauma or ectopia lentis
- Acute lens opacity can occur in rapid changes in glucose or electrolyte levels
Vitreous hemorrhage
Causes
- Causes include trauma, spontaneous retina tear, spontaneous vitreous detachment or retinal neovascularization (eg. PDMR, wet ARMD)
- Sudden, painless loss of vision
Ddx Retinal Disorders that cause acute vision loss
C/BRAO
C/BRVO
Retinal detachment
Acute maculopathy
Posterior uveitis or retinitis
Ddx Optic nerve disorders that cause acute vision loss
- Optic neuritis
- Compressive optic neuropathy
- Ischemic optic neuropathy
Retinal vein occlusion/ retinal artery occlusion
Features
RAO:
- Can result from thrombosis, embolism or CRA arteritis
- Usually a/w severe sudden painless partial or complete visual loss - RAPD +ve
- Fundus: embolus (early) or milky white infarct + cherry spot (late)
RVO:
- Typically subacute painless partial/complete visual loss
- ± RAPD+ if severe venous stasis leads to venous infarct
- ‘Blood and thunder’ appearance on fundus (disc swelling, diffuse nerve fibre/pre-retinal haemorrhage, CWSs)
Retinal detachment
Features
- May be preceded by floaters (small vitreous bleeds or vitreous detachment) and photopsia (vitreoretinal traction)
- Typically results in a painless curtain-like loss of visual field on the opposite side of the actual detachment
- Vision will be severely impaired if macula is involved
- RAPD ± (only if severe) and fundoscopy shows elevated retina with folds
Acute maculopathy
Features
- Causes include ARMD, central serous retinopathy, macular hole
- Maculopathies classically a/w central scotoma, blurred vision or visual distortion
Optic neuritis
features
- Characterized by focal demyelination of optic nerve
- ↓VA and washed out colour vision with RAPD+ of onset over a few days
- Pain on eye movement if optic sheath is involved
- May be a/w antecedent flu-like viral syndrome
- Fundus: papillitis (nerve head swelling), may be ABSENT in retrobulbar ON, optic atrophy after oedema resolved
- A/w multiple sclerosis esp in young female
Acute vision loss
Key questions for ddx
History:
- Trauma or surgery
- Transient/ acute (vascular/ infective) vs chronic/ progresive (structural causes)
- Pattern of vision loss: Monocular prechiasmal lesion; Binocular chiasmal/ post-chiasmal lesion
- Visual disturbance: Visual distortion/ metamorphopsia in maculopathy, Glare in cataracts, Rainbow haloes around lights in glaucoma
- Pain or red eye: keratitis, uveitis, acute glaucoma, optic neuritis?
- A/w neurological defects? Severe nausea and vomiting, rhinorrhea (glaucoma)?
Past opthalmic history:
- Severe myopia > retinal detachment
- Severe hyperopia > AACG
- Contact lens > Bacterial keratitis
- Previous ocular surgeries: keratitis, uveitis, corneal edema…etc
Past history:
- Vascular diseases: RAO/ RVO/ ION/ Visual pathway stroke
- DM: Vitreous hemorrhage, acute maculopathy
- MS/ Autoimmune disease: Optic neuritis
- Medications
Acute vision loss
All ddx
Transient vision loss/ Amaurosis fugax
- Retinal TIA
- Retinal migraine
- Papilledema
Ocular media:
- Keratitis
- Corneal edema/ acute glaucoma
- Anterior uveitis
- Hyphema
- Acute lens dislocation
- Vitreous hemorrhage
Retinal:
- C/BRAO, C/BRVO
- Retinal detachment
- Acute maculopathy
- Posterior uveitis/ retinitis
Optic nerve:
- Optic neuritis
- Compressive optic neuropathy
- Ischemic optic neuropathy
Ddx monocular and binocular vision loss
Monocular: prechiasmal lesion
- Peripheral loss → subtotal retinal detachment, ION, BRAO/BRVO, (chiasmal ds)
- Central loss → maculopathy (+ve scotoma) or optic nerve (-ve scotoma)
- Altitudinal → corresponding retinal vascular or optic disc disease
Binocular suggestive of chiasmal/post-chiasmal lesions
- Bitemporal → chiasmal lesions, eg. pituitary tumour, craniopharyngioma, suprasellar meningioma
- Homonymous → post-chiasmal, eg. parietal/temporal lesions, occipital infacts
Acute vision loss
- Clinical exams
□ Inspection: erythema, tearing, light sensitivity, proptosis, ptosis
□ VA/VF: not corrected by pinhole
□ Pupils: symmetry, reactivity to light, pupillary reflex, RAPD → RAPD: fairly specific for unilateral optic nerve pathologies
□ EOM testing
□ Fluorescein testing for corneal pathologies
□ IOP testing for glaucoma
□ Slit lamp examination for anterior pathologies
□ Ophthalmoscopic examination for posterior pathologies → Red reflex: loss indicates media opacity
Chronic vision loss
All ddx
Cloudy media
- Corneal opacity: corneal edema from anterior uveitis, trauma, cataract surgery, interstitial keratitis, band keratopathy, corneal scarring…etc
- Cataract
- Vitreous hemorrhage
Retinal diseases:
- DM retinopathy
- Age-related macular degeneration
- Retinitis pigmentosa
- Epiretinal membrane
- Cystoid macular edema
- Macular hole
- Choroid malignancies
Optic nerve disorders:
- Chronic glaucoma
- Optic neuropathy
Refractive error
Cataract
- Causes
- Types
- S/S
- Dx
- Mx
Cause: light-scattering opacity in the lens
- Congential cataracts
- Senile cataract (nuclear sclerotic, cortical, posterior subcapsular)
- Secondary cataract:
→ Ocular ds: trauma, uveitis, scleritis (esp if necrotizing), ↑↑myopia, ocular RT in intraocular tumours
→ Systemic ds: myotonic dystrophy, systemic steroids or chlorpromazine, DM/metabolic ds, congenital rubella, atopic dermatitis, Down’s syndrome
Symptoms:
- Gradual painless vision loss over years
- Glare
- Myopic shift
- Amblyopia
- Secondary glaucoma
Signs:
- Decrease VA in bright light (glare and pupil constriction)
- Loss of red reflex
- Lens opacity on slit lamp exam
- Refractive error
Dx: clinical exam showing lens opacity and exlusion
Mx:
- Phacoemulsification or Extracapsular Cataract Extraction (ECCE) with Intraocular Lens Implantation (IOL)
- Short course steroids and abx
- Visual rehabilitation and new glasses perscription
Glaucoma
Cause
Types/ Classification
Glaucoma:
□ Progressive optic neuropathy with characteristic VF loss
□ Usually a/w raised intraocular pressure (↑IOP) but NOT always (eg. in normotension glaucoma)
Cause:
- Increase production of aqueous humour
- Blockage of humour drainage via Schlemm’s canal or uveoscleral pathway
- Increase IOP causes compressive optic neuropathy, progressive VA loss and pathological cupping of disc
Types:
□ Chronicity: acute vs chronic
□ Aetiology: primary vs secondary
□ IOP: high vs normal
□ Angle status: open angle vs closed angle
Examples:
→ Primary open angle glaucoma (POAG)
→ Acute angle closure glaucoma (AACG)
→ Chronic angle closure glaucoma (CACG)
→ Normal tension glaucoma (NTG)22
Secondary glaucoma
Causes
S/S
Mx
Tractional retinal detachment
Causes
S/S
Mx
Exudative retinal detachment
Causes
S/S
Mx
Signs specific to dry ARMD
- Loss of normal foveal reflex
- Drusens: discrete, subretinal yellow lesions
→ Hard: small, well-defined, of limited significance
→ Soft: larger, poorly-defined, ↑risk of vision loss
→ Cf exudate: duller yellow, less well-defined, not a/w other features of ↑vascular permeability - Geographic atrophy: atrophic hypopigmented regions with visualization of choroidal vessels
- RPE focal hyperpigmentation: plaques of hyperpigmentation
Signs specific to wet ARMD
□ Subretinal fluid: stereoscopic elevation of retina
□ Subretinal neovascular membrane: grey-green membrane
□ Subretinal haemorrhage
□ Disciform scar in advanced cases (sub-RPE neovascularization leading to subretinal fibrosis)
ARMD
- Clinical tests
- Mx
Clinical tests:
□ Usually clinical dx for dry AMD
□ Fluorescein retinal angiogram for suspected wet AMD: identify location of membrane (rel. to RPE)
□ Optical coherence tomography: identify retinal oedema and subretinal fluid + monitor for Tx response
Dry ARMD Mx:
- AREDS2 forumlation oral supplement
- Risk factor mx: stop smoking
- Self-monitor with Amsler grid
Wet ARMV Mx:
- Intravitreal VEGF inhibitor
- Photodynamic therapy
- Direct focal laser
- AREDS2 oral supplement
