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Ophthalmology SC011: Acute Visual Loss Flashcards

1
Q

Causes of Acute vision loss

A

Break down of >=1 components which allow vision:
1. Cornea
2. Lens
3. Vitreous
4. Retina
5. Optic nerve

***Classification:
- Transient vs Persistent
—> Acute vs Chronic
—> Painful acute vs Painless acute

***Transient:
1. Amaurosis fugax
2. Migraine

Persistent:
1. Cornea
2. Anterior chamber
3. Lens
4. Vitreous
5. Retina
6. Macula
7. Optic disc

***Painful acute:
1. Keratitis
2. Glaucoma
3. Uveitis

***Painless acute:
1. Retinal vascular diseases (RVO, RAO)
2. Vitreous haemorrhage
3. Retinal detachment involving macula
4. Age-related macular degeneration (AMD)
5. Uveitis / Retinitis
6. Optic neuropathy
7. Optic neuritis

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2
Q

Approach to Acute vision loss

A
  1. History
    - Past medical
    - Co-morbidities
    - Ocular history
    - Presenting history (Trauma?)
  2. P/E
    - VA
    - **VF
    - **    IOP
    - RAPD
    - ***Anterior segment (Slit Lamp)
    - Dilated fundal exam
    (- Red light reflex)
  3. Investigations
    - Imaging
    —> Anterior segment: **Specular microscopy (look at cells at back of cornea), **Optical coherence tomography (OCT), Keratometry, Corneal tomography
    —> Posterior segment: USG, **OCT, **Fluorescein angiography
    - Electroretinography (ERG), Electrooculography (EOG) (for neurological conditions)
    - Systemic: CT / MRI, Blood (e.g. for inflammatory conditions), CXR etc.
  4. Diagnosis
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3
Q

History taking

A

Co-morbidities:
1. Vascular (RVO, RAO)
- HL
- HT
- DM

  1. Microvascular (DR)
    - DM
  2. Bleeding (Vitreous haemorrhage, Hyphaema, Retinal haemorrhage, Haematoma)
    - Trauma
    - Bleeding tendency
    - Episode of vomiting
    - Chronic coughing
  3. Neuritis (Optic)
    - **Multiple sclerosis
    - **    Autoimmune diseases

Previous Ocular diseases

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4
Q

Physical examination

A
  1. Visual acuity
  2. IOP (Applanation, NCT) —> Glaucoma (esp. AACG)
  3. RAPD
    - rely on consensual light reflex during swinging torch test
  4. Anterior segment (Slit Lamp)
  5. Dilated fundal exam
    (6. Red light reflex)
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5
Q

Slit lamp exam

A
  • Anterior + Posterior segment visualisation
  • Slit allows delineation of different structures + abnormalities (i.e. cornea, anterior chamber, lens, anterior vitreous)
  • can do Measurement (e.g. corneal thickness) + Photography
  • Fluorescence staining: Filters for highlighting defects
  • Diffuse light: visualisation of most eye structures (e.g. lid, sclera)
  • Slit light: differentiate depth of structures
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6
Q

Dilated fundal exam

A
  • Necessary to dilate pupil for a full fundus exam + visualisation of posterior + peripheral retina

Indirect ophthalmoscopy:
- Binocular (stereo) virtual view of fundus
- Much larger field of view than direct ophthalmoscopy

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7
Q

Transient Acute visual loss

A
  1. Amaurosis fugax
    - TIA caused by abrupt reduction in blood flow
    - Refer to physicians for CVS workup
    - Nothing ophthalmologist need to do
  2. Migraine
    - Vasospasm
    - Visual disturbances (**Aura)
    —> often precedes headache (may not have headache at all: Ocular migraine)
    —> **    flashing / **migrating lights (enlarging bright, curved, **zig-zag lines, move from peripheral to centre, constant rather than a moment of flash, lasting ***10-20 mins)
    —> blurred vision
    —> occasional nausea sensation
    - Differentiate from “flashes and floaters” (閃光燈) —> PVD / Retinal detachment
    - Refer to physicians for workup in recurrent / severe cases
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8
Q

***Persistent Acute visual loss

A

By anatomy

Cornea:
1. Epithelial defect
2. Corneal trauma
3. **Edema (AACG)
4. **Ulcer (Keratitis)
—> Painful

Anterior chamber:
1. Hyphaema
2. ***Uveitis (cells, flare)

Lens:
1. **Cataract (can be acute if traumatic)
2. Subluxation
3. **Dislocation

Vitreous:
1. ***Haemorrhage

Retina:
1. **Vascular occlusions
2. Haemorrhage
3. **Detachment

Macula:
1. **Hole
2. Haemorrhage
3. **Edema (Fluid)
4. Exudates

Optic disc:
1. ***Swelling (Optic neuritis, Arteritic ischaemic optic neuropathy (AION))

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9
Q

Painful acute visual loss

A

Pain from highest to lowest:
1. Cornea
- most painful (∵ most sensitive, have most nerve endings), may be blunted in DM, previous herpetic keratitis (i.e. Herpes simplex keratitis)
- usually BOV
- **trauma, contact lens use, foreign body, evert eyelids for foreign body
- Slit lamp exam
—> **Stain for Epithelial defect, look for Foreign body, Corneal structure

  1. Glaucoma
    - from BOV to severe vision loss
    - IOP (acute ↑ of IOP, very high): N+V, headache right behind eye
    - Slit lamp exam
    —> Injection, **Fixed mid dilated pupil, **Corneal edema, ***Shallow anterior chamber
  2. Uveitis
    - BOV, photophobia
    - IOP normal / ↑
    - Slit lamp exam
    —> **Conjunctival injection (Ciliary flush), **Anterior chamber cells, Fibrin, ***Hypopion
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10
Q

Cornea: Keratitis

A

Causes:
- Bacterial, Viral, Fungal, Amoeba

History:
- Contact lens use (esp. overnight, reuse) —> Bacterial / Amoeba
- Trauma —> Fungal
- Contact with dirty water —> Amoeba

Management:
1. Refer to ophthalmologist for
- swab / scraping for culture
- culture contact lens case, fluid + lens
2. Symptomatic treatment
3. Broad spectrum topical antibiotics —> switch to Fortified antibiotics according to culture results

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11
Q

Acute angle closure glaucoma

A

Test for anterior chamber depth: use light to illuminate one side of eye, if shallow chamber —> light cannot pass through bulging of eye

Risk factors:
- **Female
- Asian
- Old age
- **Hyperopia (short axial length)
- ***Shallow anterior chamber
- Family history

Precipitating factors:
- Topical **mydriatics
- Systemic **anticholinergics (e.g. antihistamine, bronchodilator, antipsychotic) —> dilate pupil
- Dim illumination
- Accommodation (e.g. reading) —> thicker lens

Acute symptoms:
1. BOV
2. Eye pain
3. Headache
4. N+V
5. ***Halos around lights

Acute signs:
1. Injection
2. Fixed mid-dilated pupils
3. **Corneal edema
4. ↓ VA
5. ↑ IOP
6. **Shallow anterior chamber

Treatment (↓ IOP ASAP):
1. **Constrict pupil (Pilocarpine)
2. **Systemic acetazolamide:↓ IOP
3. Topical β blockers, α agonists, CAI, Prostaglandin analogue: ↓ IOP (high IOP might not allow eye drops to penetrate cornea)
4. ***Peripheral iridotomy (PI): ↓ recurrence risk
5. Others
- Argon laser iridoplasty
- Lens extraction
- Surgical PI

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12
Q

Uveitis

A

Uvea: **Middle layer of eye
- **Anterior: Iris, Ciliary body
- ***Posterior: Choroid

Location of inflammation (inflammatory cells):
1. ***Anterior
- most common uveitis (>50%)
- inflammation mostly in anterior segment
—> Iritis, Cyclitis

  1. Intermediate
    - middle portion of globe (i.e. vitreous, pars plana, peripheral retina)
    —> Posterior cyclitis, **Par planitis, **Vitritis
  2. Posterior
    - choroid, retina (retinochoiditis, retinitis, neuroretinitis)
    —> **Choroiditis, **Retinitis
  3. ***Pan
    - no predominant place but inflammation seen through out

Causes of acute blurred vision due to uveitis:
1. **Corneal edema (∵↑ IOP, inflammation)
2. ↑ IOP
3. **Macula edema (cause severe visual disturbance)
4. **Exudative retinal detachment (fluid builds up behind retina)
5. **Rhegmatogenous retinal detachment (hole in retina)
6. Vitreous opacities (cells, haemorrhage)
7. Retinitis
8. Neuritis

Symptoms:
- BOV
- **Photophobia
- **Pain
- ***Tearing

General signs:
- ↓ VA
- Injection
- Possibly ↑ IOP
- Anterior chamber cells, Fibrin, Hypopion (cells settle in anterior chamber)

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13
Q

Anterior uveitis

A

Causes:
1. ***Idiopathic (50%)

  1. ***HLA B27 related (20%)
    - Ankylosing spondylitis
    - Reiter’s disease
    - IBD
    - Psoriasis
  2. Viral (10%)
    - Herpes simplex
    - Herpes zoster
    - CMV
  3. Poster Schlossman syndrome
  4. Fuch’s heterochromic iridocyclitis
    - Unilateral, chronic, non-granulomatous anterior uveitis of unknown cause
  5. Iatrogenic
    - Surgical complications
    - Trauma
    - Implants (IOL)
    - Corneal transplants

Classical signs:
1. **Ciliary flush (only sign seen by naked eye —> history taking very important)
2. **Anterior chamber cells (ACC) (inflammatory cells floating in aqueous, slit lamp required)
3. ***Keratic precipitates (KP) (whitish dots behind cornea, slit lamp required)

Other signs:
4. Fibrin
5. Flare
6. **Hypopion
7. **Peripheral anterior synechiae (PAS) (iris adhere to the angle / cornea —> can cause ↑ IOP)
8. **Posterior synechiae (PS) (iris adhere to anterior lens capsule —> can cause ↑ IOP)
9. Iris bombe
10. **Corneal edema

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14
Q

Intermediate uveitis

A

Causes:
1. Idiopathic (***Pars planitis)

  1. Systemic
    - MS
    - Sarcoidosis
    - CNSL
    - IBD
  2. Infective
    - Toxocaria
    - Lyme
    - HTLV (Human T cell leukaemia-lymphoma virus)

Signs:
1. **Vitreous cells
2. **Snowbanking
3. ***Snowballs
4. Retinal vascular sheathing
5. Neovascularisation
6. Macula edema
7. Anterior chamber cells, PAS, PS

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15
Q

Posterior uveitis

A
  1. Retinitis
    - Focal: Idiopathic, Toxoplasmosis, Onchocerciasis, Cysticercosis, Masquerade
    - Diffuse: Idiopathic, Syphilis, HSV, CMV, VZV, Sarcoidosis, Candidiasis, Masquerade
  2. Choroiditis
    - Focal: Idiopathic, Toxocariasis, **TB, Masquerade
    - Diffuse: Idiopathic, **    Vogt–koyanagi–harada syndrome (VKH), Histoplasmosis (POHS), Multifocal choroiditis, Sympathetic ophthalmitis, Sarcoidosis, ***TB, Whit dot syndromes
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16
Q

Panuveitis

A

Causes:
1. Idiopathic
2. **Endophthalmitis (a type of uveitis)
- Endogenous vs Post-operative
3. Sarcoidosis
4. **Vogt–koyanagi–harada syndrome (VKH) (common in Asia)
5. **Behçet’s disease
6. **TB
7. Syphilis

17
Q

Infective endophthalmitis

A

Work up:
- History: Recent ocular surgery, **Liver abscess (*Klebsiella)
- Signs: BOV, pain, injection
- P/E

Investigations:
- **B scan (USG of eye)
- **USG liver
- CT abdomen
- Tap (anterior chamber / vitreous) + Jab (Antibiotics)

Treatment:
1. **Intravitreal antibiotics
2. Consider pars plan vitrectomy with IOL explantation
3. Consider topical fortified antibiotics / topical steroids for inflammation
4. **Systemic antibiotics for liver abscess

18
Q

Painless acute vision loss

A

Painless: more in posterior
(Painful: more in anterior, pressure-related)

  • History very important
  • Important DDx:
    1. Retinal vascular diseases (RVO, RAO)
    2. Vitreous haemorrhage
    3. Retinal detachment involving macula
    4. Age-related macular degeneration (AMD)
    5. Uveitis / Retinitis
    6. Optic neuropathy (e.g. Optic neuritis)
19
Q

Retinal vein occlusion

A

Risk factors:
- **HT
- **DM
- Smoking
- Obesity
- Hypercoagulation disorders (Protein C, S deficiency, APLS)
- Glaucoma

Systemic associations:
- ***HL
- SLE
- Sarcoidosis
- TB
- Syphilis
- Multiple myeloma
- Cryoglobinaemia
- Leukaemia
- Lymphoma
- Sickle cell disease

4 Retinal veins branches:
1. Superotemporal
2. Inferotemporal
3. Superonasal
4. Inferonasal

Classification based on **Region:
1. Branch RVO (BRVO)
- only **1 branch involved
- may be asymptomatic / scotoma / BOV

  1. Hemi RVO
    - ***>=2 branches involved
    - subcategory of Central RVO
  2. Central RVO (***CRVO)
    - always symptomatic, central scotoma / diffuse BOV depending on whether it is ischaemic / non-ischaemic
    —> Check ischaemia with fluorescence angiogram to look for areas with non-perfusion

**Classification based on **Perfusion:
1. Ischaemic
2. Non-ischaemic

Signs:
- **Flame-shaped haemorrhage (elongated, bleeding in retinal nerve fibre layer)
- Dot haemorrhage
- Blot haemorrhage
—> Different shape of haemorrhage
—> Different location of haemorrhage in terms of **layer
—> Tighter area —> Smaller haemorrhage

Management:
1. **Intravitreal anti-VEGF (if NV in ischaemic type, macular edema)
2. PRP (if NV in ischaemic type)
3. **Intravitreal steroid (in macular edema)

**Complications:
1. **Neovascular glaucoma
2. **Vitreous haemorrhage
3. **Macular edema

20
Q

Retinal artery occlusion

A

Risk factors:
- HT
- HL
- Hyperviscosity syndromes

Causes (**Embolic usually):
1. **Carotid artery atherosclerosis
2. ***Cardiogenic embolism
3. Small artery disease at Central retinal artery
4. Vasculitis (e.g. GCA)

Retinal artery:
- Retina blood supply as retinal artery branches out from optic disc

Classifications:
1. Branch RAO
- ***distal branches of retinal artery

  1. Central RAO (more common)
    - retinal artery ***emboli

Signs:
1. **Ischaemic retinal whitening + edema
2. **Hollenhorst plaque
3. **Cherry red spot
4. **Arterial thinning

Investigations:
1. **Fluorescein angiography
2. **Carotid doppler
3. ***ECG / Echo
4. ESR / CRP, CBC

Management:
1. **Ocular massage —> shake off emboli
2. **Rebreathe into paper bag —> Vasodilation —> Reperfusion
3. **IV Acetazolamide / Mannitol / Topical eyedrops (↓ IOP)
4. **AC paracentesis
5. ***Hyperbaric O2

Complications:
1. Neovascularisation
2. Vitreous haemorrhage

21
Q

Posterior Vitreous Detachment

A

Liquefaction of vitreous with age —> detach from retina

S/S
1. ***Photopsia (i.e. Flashes)
- Vitreous traction
—> Vitreous comes away
—> Retina stimulated
—> Photoreceptors all fire at once
—> Flashes (perceived by brain)

  1. ***Web like floaters
    - Vitreous detachment
    - Non-specific
    - Any vitreous opacities: haemorrhage, debris, hyaloid, condensation, syneresis etc.
    - Everyone has, only amount / ↑ in floaters matters
  2. ***Weiss ring
    - posterior border of vitreous where it still attaches to the optic disc

Complications:
1. Subretinal fluid (SRF) —> Field defect +/- BOV (indicate retinal detachment)
2. Retinal tear —> Subretinal fluid (SRF) —> Field defect +/- BOV (indicate retinal detachment) —> RRD
3. ***Rhegmatogenous retinal detachment (RRD)
4. Vitreous haemorrhage

Management:
1. Exclude retinal tear / RRD
2. Close observation for RRD
3. Refer to ophthalmologist for full assessment

22
Q

Retinal detachment

A

Risk factors:
- ***High myopia (>-6D)
- Family Hx
- Eye rubbing (Eczema)
- Systemic disease (Marfan)

Classification:
1. Rhegmatogenous (causes: PVD, Uveitis, Traumatic retinal tear)
2. Tractional (causes: PDR)
3. Exudative (causes: Choroid neoplasms, Central serous retinopathy, Uveitis)

Symptoms / History:
- **Posterior vitreous detachment (Weiss ring)
- **Retinal hole / break / heme (↑ in floaters) (e.g. Horseshoe tear)
- ***Subretinal fluid (SRF) + Retinal detachment (flashes, field loss, curtain (∵ SRF travels down due to gravity (由上至下扯開retina)), BOV)

Management:
1. **Laser retinopexy / **Cryoretinopexy (for small, peripheral RRD)
2. **Scleral buckle (external technique, conventional approach)
3. **Pneumatic retinopexy (internal technique, office procedure only)
- temporary gas tamponade
4. ***Pars plana vitrectomy (used in more complicated cases)
- all of central and peripheral vitreous removed
- retina flattened intraoperatively by air bubble or fluorocarbon (heavier than water)
5. Complex vitreoretinal surgery (if further complications occur)

23
Q

Vitreous haemorrhage

A

Causes:
1. Trauma
- Young patients

  1. Neovascularisation
    - **PDR
    - **    CNV (Choroidal neovascularisation)
    - **Vascular occlusions
    - Retinitis
    - Vasculitis
    - **    Uveitis
  2. ***Posterior vitreous detachment (rare)
    - Must look for retinal hole / avulsed vessels
  3. Bleeding tendencies, Blood dyscrasia

Fundoscopy:
- Very difficult —> have to rely on Hx, USG, B-scan

S/S:
- BOV
- **Diminished red reflex
- **No RAPD (SpC Revision)

24
Q

Diabetic retinopathy

A

Non-proliferative:
- Vision affected:
1. Macula edema
2. Macula exudates

  • Vision not affected:
    1. Dot + Blot haemorrhage
    2. Flame haemorrhage
    3. Extrafoveal exudates

Proliferative:
1. Vitreous
- Haemorrhage (Preretinal / Subhyaloid: blood covering vessels, overlying retina)
—> If no posterior vitreous detachment
—> no vitreous haemorrhage (only preretinal haemorrhage)

  1. Macula
    - Edema
    - Haemorrhage
    - Exudates
    - Detachment
  2. Retina
    - Traction and Rhegmatogenous detachment
    - Fibrovascular changes
25
Q

Age-related macula disease (AMD)

A
  • ***Age >50

Risk factors:
- **Smoking
- **Female
- CVS risk
- ***Hypermetropia / Hyperopia (other diseases: APAC, Pseudo-papilledema)

Dry (90%) vs Wet

Signs:
- ***Metamorphopsia
- BOV

Features:
1. ***Drusen
—> hard <63 microns (less risk of converting to wet AMD)
—> soft, larger, confluent, pale yellow, poorly defined (more dangerous)

  1. RPE hyperpigmentation / geographical atrophy
  2. **Subretinal haemorrhage / fluid
    - Bleeding from choroid (∵ **    Choroidal neovascularisation (CNV)) —> present more acutely
  3. Pigmented epithelial detachment
26
Q

Dry AMD

A

Treatment:
1. Education
2. **Stop smoking
3. Dietary changes
- Intake macular carotenoids: spinach, cabbage, broccoli
- Vitamins: **AREDS2 supplement (Vit C, E, Alpha carotene, Zinc) —> only proven supplement
4. Regular ***AMSLER grid monitoring

27
Q

Wet AMD

A

Treatment:
1. Supportive treatment ~ Dry AMD

For subretinal fluid, haemorrhage:
2. ***Intraocular Anti-VEGF injections to control CNV (Choroidal neovascularisation)

  1. **Photodynamic therapy (for **Polypoidal Choroidal Vasculopathy - PCV variant (subtype of AMD))
  2. Focal laser ablation for extra-macular lesions
28
Q

Causes of CNV

A
  1. ***AMD (top DDx)
  2. Degenerative
    - Myopic
    - Angioid streaks
  3. Trauma
    - Choroidal rupture
    - Laser (iatrogenic)
  4. Inflammatory
    - ***Vogt-Koyanagi-Harada disease
    - Primary ocular histoplasmosis
    - Multifocal choroiditis
    - Serpiginous chorioretinopathy
    - Bird shot retinochoroidopathy
    - Punctate inner choroidopathy
  5. Dystrophy
    - Best’s disease
  6. Choroidal tumour
  7. Idiopathic
29
Q

Arteritic Ischaemic Optic Neuropathy

A
  • > 50 yo
  • Temporal arteritis —> occlusion of Ophthalmic artery

S/S:
- Jaw claudication (pain with chewing)
- Scalp tenderness (tenderness with hair combing)
- Proximal muscle + joint aches (***polymyalgia rheumatica)
- Anorexia
- Weight loss
- Fever

Signs:
- **Afferent pupillary defect
- **Pale swollen optic nerve
- ***Optic atrophy (as ON edema resolves)

Management:
- Immediate ESR
- **Temporal artery biopsy
—> look for Giant cell arteritis: inflammatory infiltrate that is granulomatous, sometimes with giant cells
- **High dose steroid

30
Q

Optic neuritis

A

Inflammation of Optic nerve:
- Papillitis
- Retrobulbar neuritis
- Neuroretinitis

**Typical vs **Atypical Optic neuritis:
- Typical: ***Multiple sclerosis associated

Typical features:
1. 20-50 yo female (F:M = 3:1)
2. **Unilateral BOV worsening over hours / days
3. **Colour vision affected, Impaired VA, VF
4. Retrobulbar pain
5. **RAPD +ve
6. Pain with **eye movement

Prognosis:
- Spontaneous recovery starts ~2 weeks

Management:
- Refer to ophthalmologist / neurologist for atypical features (anything not above 5 features e.g. bilateral)

31
Q

Summary

A

Acute visual loss:
- Obvious reasons, History of trauma
- Think anatomically:
1. Cornea: edema, painful, tearing, injected, “cannot open eye”
2. Lens: very rare, dislocated lens? —> slit lamp to look at lens
3. Retina: painless, severe BOV, **field defect (pathognomonic for retinal detachment, BOV + patient realise it is there unlike neurological field defect: entirely black, patient do not know themselves), flashes, floaters
4. Vitreous haemorrhage: loss of red reflex, history of **DM
5. Neurological: colour vision + contrast sensitivity affected (red colour affected first), RAPD, Unilateral BOV

Hint:
- Painful: Cornea, ↑ IOP
- Painless: Neurological, Retinal
- Transient: Vascular
- Persistent: Can be anything

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