Acute Visual Loss Flashcards
2 min approach of acute visual loss
Red reflex: media problem
Pupillary light reflex: conduction problem
Fundoscopy examination
Causes of reduce/absent red reflex
Causes of white reflex
Reduce/absent red reflex
- corneal scar
- cataract (lens)
- hyphaema (ant chamber)
- vitreous haemorrhage (vitreous)
- retinal detachment (retina)
White reflex
- retinoblastoma
- persistent fetal vasculature (PFV)
- retinopathy of prematurity (ROF)
- coats ds
- toxocariasis
Pupillary light reflex
- what is the normal pupil size
- the causes of abnormal pupil size
- normal vs abnormal RAPD
- 2-4 mm
- dilated (>4mm): third nerve palsy
- constricted (<2mm): opiate, horner syndrome, argyll robertson pupil (neurosyphilis)
- normal rapd: ABSENT
- abnormal rapd: PRESENT dt optic neuropathy (2nd cranial nerve abnormality), massive haemorrhage
Ie for optic neuropathy
- glaucoma
- optic neuritis
- AION
- CRAO
- CRVO
- Massive RD
- Large macula lesion
2 min approach fundoscopy
Optic disc margin
Normal: well defined, clear margin
Abnormal: blurred margin (optic disc swelling)
Optic disc colour
Normal: pink (slightly orange and red)
Abnormal: pale/hyperemic
Cup to disc ratio
Normal: less than 0.5
Abnormal: more than 0.7 (ie: glaucoma)
Macular region: must look at the light source
Normal: no drusen, no haemorrhage, no exudates
Abnormal: hard exudate or haemorrhage (PDR, NPDR), drusen (degeneration/ARMD)
Acute vs subacute
Acute: within seconds > vascular
Subacute: hours > inflammatory
Causes of vitreous haemorrhage
- proliferative neuropathy: PDR, CRVO, BRVO
- posterior vitreous detachment
- retinal detachment
Findings on fundoscopy;
Proliferative retinopathy
- neovascularization
- boat shaped haemorrhage
Findings on fundoscopy;
CRVO
- flamed shaped/red dot haemorrhage in all quadrant of retina
- tortous vessels
- cotton wool spots at macula region
Classification of CRVO
Ischemic CRVO
- extensive blockage
- very poor vision
- positive RAPD
- neovessel formation: vitreous haemorrhage, rubeosis, tractional retinal detachment
Non ischemic CRVO
- partial blockage
- good vision
- negative RAPD
- no neovessel formation
Symptoms and signs of BRVO
Symptoms: sudden poor vision, visual field defect
Signs: RAPD negative, intraretinal haemorrhage, cotton wool spot, dilated/tortuous vessels, +/- macula edema
Most common site at superotemporal quadrant
Patho proliferative retinopathy: CRVO/BRVO/PDR
BRVO/CRVO causing increase in VEGF. Leads to neovascularisation which cause vitreous haemorrhage.
Ix of vitreous haemorrhage
- RAPD
- projection of light
- B scan ultrasound: retinal detachment, posterior vitreous detachment
Mx of vitreous haemorrhage
-Non clearing VH: vitrectomy
- tx underlying cause: CRVO, BRVO, PDR, retinal tear, PVD
Types of retinal detachment
- rhegmatogenous RD
- tractional RD: proliferative DR
- exudative RD: choroiditis, pre eclampsia
Symptoms of posterior vitreous detachment
- floaters
- flashes
- visual field defect
- poor vision: macular involvement
Risk factors of posterior vitreous haemorrhage
- myopia
- blunt trauma
- Intraocular surgery
Management of post vitreous haemorrhage
- scleral buckle
- vitrectomy
Symptoms of CRAO
- sudden reduced vision
- painless
- previous hx of amaurosis fugax
- u/l medical problem: HTN, DM, hyperlipidemia, valvular heart ds
Signs of CRAO
- pallor retina
- cherry red spot
- attenuation of artery
- severe visual loss
- positive RAPD
- embolus in retina vessel
Mx of CRAO
- hyperventilate
- carbogen 95% oxygen and 5% oxygen
- digital massage
- oral acetazolamide
- AC paracentesis to reduce IOP
RF of CRAO
- age older than 70y/o
-atherosclrosis - high cholesterol
- hypertension
- arteritis
- young: connective tissue ds, valvular heart ds, sickle cell ds
Types of ARMD
- wet ARMD: subretinal haemorrhage
- dry ARMD- drusen
Symptoms of ARMD
- metamorphopsia
- central scotoma
- painless
Investigation of ARMD
- Amsler grid test
- Optical Coherence Tomography (OCT) macula
- Fundus Fluorescein Angiography
- Indocyanine green
