Cortical Blindness

Cortical Blindness

Severe, often total, visual loss in both eyes lesions optic radiations or visual cortex in both cerebral hemispheres

Common causes of cortical blindness in adults :

• bilateral infarctions of occipital lobe cortex 
• bilateral infarction of posterior optic radiations 
• reversible posterior leukoencephalopathy syndrome (RPLS)
• trauma

Common causes of cortical blindness in children : 

• periventricular leukomalacia 
• cerebral maldevelopment
• trauma

Reversible causes of cortical blindness: 

• RPLS
• focal status epilepticus
• metabolic encephalopathy (hypoglycemia, hepatic encephalopathy, post dialysis) 
•acute disseminated encephalomyelitis 
• multiple sclerosis
•occipital tumor
•brain abscess
• meningitis

MRI reliably often detects lesion except in

• metabolic encephalopathy. 
•Creutzfeldt–Jakob disease (CJD).
• meningoencephalitis.
• focal status epilepticus.

 If MRI is negative and patient is otherwise neurologically intact, the diagnosis is likely to be psychogenic blindness or malingering.

Cortical Blindness Clinical Findings:

• Binocular symmetric visual loss. 
• normal-appearing eyes and 
• normal pupillary reactions to light.
• Visual loss usually severe, often total( NPL).
• Visual hallucinations often present.
• Patients may insist (confabulate) that they can see (Anton syndrome = denial of blindness).
• No other neurologic abnormalities. 
• Bilateral homonymous hemianopias (VF defects) evident on visual field testing.

Investigation of Cortical Blindness

• VF for homonymous hemianopia. 
• Brain MRI may show The causes but may negative. 
• Electroencephalogram should be performed if focal status epilepticus is a consideration.
• Rule out hypoglycemia and hepatic encephalopathy, especially if MRI is negative.
• Lumbar puncture to rule out infection if no other explanations exist.

Differential Diagnosis of Cortical Blindness

• functional or hysterical Visual loss.
• malingering.

Cortical Blindness Videos:

https://m.youtube.com/watch?v=-R7ldaCqZZY

Cortical Visual Impairments – YouTube

Cortical Blindness PPT power point presentations:

Pediatric Cortical Visual Impairment slideshare

https://www.slideshare.net/DMAINO/aao-pediatric-cortical-visual-impairment

Pediatric Cortical Visual Impairment Dominick M. Maino, OD, MEd, FAAO, FCOVD-A Professor of Pediatrics/Binocular Vision Illinois Eye Institute/Illinois College of Optometry Lyons Family Eye Care Chicago

Cortical blindness in preeclemptic patients slideshare

https://www.slideshare.net/SULEAKIN/cortical-blindness-in-preeclemptic-patients

Pediatric Cortical Visual Impairment

https://www.slideshare.net/DMAINO/pediatric-cortical-visual-impairment-60676502

This course presents the latest information concerning cortical visual impairment, its etiology, diagnosis and treatment. Various topics reviewed include cortical vs cerebral visual impairment, ventral/dorsal visual streams, visual acuity, and contrast sensitivity. Also discussed are various retinoscopy techniques, overlapping functional vision disorders, and visual stimulation/therapy for these disorders.
Course Objectives 
At the end of this course, the participant will:
Be able to identify cortical vs cerebral visual impairment
Be able to access various vision functions such as visual acuity, contrast sensitivity, oculomotor and accommodative disorders
Be able to treat the diagnosed vision problems with all the tools available to the optometrist (spectacles, low vision devices, vision rehabilitative techniques)
Be aware of and use outside resources to supplement and add to any therapeutic interventions recommended.