Opthalmology - Vision Loss, Disorders of ocular media and posterior eye

Question 1

Ddx transient vision loss

Differentiating features

Answer 1

Retinal TIA

**Retinal Migraine **

**Papilledema **

Question 2

Ddx ocular media disorders that cause acute vision loss

Answer 2

• Keratitis
• Acute glaucoma/ corneal edema
• Anterior uveitis
• Hyphema or trauma
• Acute lens changes/ lens dislocation/ lens opacity
• Vitreous hemorrhage

Question 3

Hyphaema

Features

Answer 3

• 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

Question 4

Acute lens changes

Causes

Answer 4

• 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

Question 5

Vitreous hemorrhage

Causes

Answer 5

• Causes include trauma, spontaneous retina tear, spontaneous vitreous detachment or retinal neovascularization (eg. PDMR, wet ARMD)
• Sudden, painless loss of vision

Question 6

Ddx Retinal Disorders that cause acute vision loss

Answer 6

C/BRAO
C/BRVO
Retinal detachment
Acute maculopathy
Posterior uveitis or retinitis

Question 7

Ddx Optic nerve disorders that cause acute vision loss

Answer 7

• Optic neuritis
• Compressive optic neuropathy
• Ischemic optic neuropathy

Question 8

Retinal vein occlusion/ retinal artery occlusion

Features

Answer 8

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)

Question 9

Retinal detachment

Features

Answer 9

• 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

Question 10

Acute maculopathy

Features

Answer 10

• Causes include ARMD, central serous retinopathy, macular hole
• Maculopathies classically a/w central scotoma, blurred vision or visual distortion

Question 11

Optic neuritis

features

Answer 11

• 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

Question 12

Acute vision loss

Key questions for ddx

Answer 12

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

Question 13

Acute vision loss

All ddx

Answer 13

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

Question 14

Ddx monocular and binocular vision loss

Answer 14

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

Question 15

Acute vision loss

• Clinical exams

Answer 15

□ 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

Question 16

Chronic vision loss

All ddx

Answer 16

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

Question 16

Cataract

• Causes
• Types
• S/S
• Dx
• Mx

Answer 16

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

Question 16

Chronic vision loss

Key questions
Clinical exams

Answer 16

History:
Pattern of visual loss?
- Gradual blurring or dimming of vision
- Distortion → usually maculopathy
- Central scotoma → maculopathy (+ve) or optic neuropathy (-ve)
- Constricting VF → chronic glaucoma (or retinitis pigmentosa)

Other visual disturbances?
- Glares → cataract
- Rainbow haloes → glaucoma

Pain? chronic dull eye pain may occur in glaucoma

Systemic diseases? DM, HTN

P/E:
→ VA, VF
→ pattern of visual loss
→ Pupil exams and RAPD
→ RAPD = optic n. pathology (usually)
→ Red reflex lost in ↑ocular media opacity
→ Fundoscopy for posterior eye pathologies

Question 17

Cataract surgery complications

Answer 17

• Suture-related: corneal astigmatism, irritation
• Endophalmitis
• Vitreous loss (risk glaucoma, retinal traction)
• Iris prolapse
• Cystoid macular edema
• Retinal detachment
• Phacolytic uveitis
• Posterior capsule opacification

Question 18

Glaucoma

Cause
Types/ Classification

Answer 18

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

Question 19

Primary Open Angle Glaucoma

• Cause
• S/S
• Clinical tests
• Dx
• Mx

Question 20

Primary angle closure glaucoma
- Cause
- S/S
- Clinical tests
- Dx
- Mx

Question 21

Secondary glaucoma
Causes
S/S
Mx

Answer 21

Question 22

Vitreous hemorrhage

Causes
S/S
Clinical tests
Mx

Question 23

Floaters/ PVD - Cause - S/S - Cx - Tx

Question 24

Retinal detachment Types Causes

Question 25

Rhegmatogenous retinal detachment Causes S/S Clinical tests Tx

Question 26

Tractional retinal detachment Causes S/S Mx

Answer 26

Question 27

Exudative retinal detachment Causes S/S Mx

Answer 27

Question 28

Retinitis pigmentosa Causes S/S Dx Mx

Question 29

Choroidal neoplasms Types S/S Dx Mx

Question 30

Maculopathies Key features

Answer 30

Features of macular diseases: □ Blurred central vision □ Metamorphopsia (distorted vision) due to disturbance in arrangement of photoreceptors → Micropsia (↓size) or macropsia (↑size) □ Central scotoma due to part of photoreceptor being covered

Question 31

Age-related macular degeneration Cause Types Classical symptoms

Answer 31

Cause: degenerative ds of macula leading to loss of central vision Types: - Dry (non-exudative) AMD with geographic atrophy and drusen - Wet (exudative) AMD with choroidal neovascularization, neovessels grow into subretinal space to form Subretinal Neovascular Membrane and Subretinal Hemorrhage Symptoms: □ Asymptomatic in early stages □ Visual disturbance: usually gradual but may be acute in wet AMD (due to acute subretinal haemorrhage) → Visual blurring → Metamorphopsia: more common in wet AMD - Amsler grid: used to assess progression of AMD → Central scotoma

Question 32

Signs specific to dry ARMD

Answer 32

- 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

Question 33

Signs specific to wet ARMD

Answer 33

□ 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)

Question 34

ARMD - Clinical tests - Mx

Answer 34

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

Question 35

Retinal vascular diseases Signs of retinal vascular leakage

Question 36

Signs of retinal vascular occlusion

Question 37

Retinal artery occlusion Causes Types S/S

Question 38

Retinal vein occlusion

Question 39

Diabetic retionpathy

Question 40

Hypertensive retinopathy