What Is Cortical Blindness?

Cortical blindness is a type of central visual dysfunction caused by toxins in the occipital lobe cortex due to toxins or vasospasm and ischemia, and the most common is vasospasm. The clinical manifestations are complete loss of binocular vision, normal pupillary light reflection, normal fundus, and hemiplegia. Corticosteroids and vasodilators are generally used, but the results are not very satisfactory.

Basic Information

English name

cortical blindness

Visiting department

Ophthalmology

Common causes

Caused by toxins in the occipital cortex of the brain, or caused by vasospasm and ischemia

Common symptoms

Complete loss of binocular vision

Causes of cortical blindness and common diseases

A common cause of cortical blindness is cerebrovascular disease. About 50% of cortical visual impairment is caused by focal, occlusive cerebrovascular disease, and is rare in encephalitis, brain tumors, brain trauma, hypoxia, degeneration, and demyelinating disease. It can also be one of the complications of carbon monoxide poisoning, post-seizure, cerebral angiography, and migraine.

Differential diagnosis of cortical blindness

1. Hysterical blindness and fraud

(1) Cortical blindness often has various primary diseases that can cause cortical blindness, such as cerebrovascular disease and trauma. Hysteria blindness often has a history of trauma. There is a certain psychological motivation for scammers.

(2) Cortical blindness is often accompanied by other organic symptoms, while hysterical blindness and swindle blindness often have other neurological functional symptoms, and there are many changes.

(3) Use a strong beam to dazzle the eyes suddenly or use a sharp object to make a glare action. Cortical blindness has no blinking reflection and avoidance response, while hysteria blindness and fraud blindness often have blinking reflection and avoidance response.

(4) Blind suggestion or psychotherapy is ineffective, hysteria blind suggestion or psychotherapy is effective.

(5) Optokinetic nystagmus cannot occur in cortical blindness, but rickets and scam blind optokinetic nystagmus exist.

(6) Electrophysiological examination of the eye: Cortical blindness VEP was abnormal, but hysterical blindness and fraudulent blindness were normal. Rickets blindness, fraud blind EEG open and closed eye response exists.

2. Ophthalmic diseases

Various eye diseases can also cause vision loss in both eyes, including corneal, retina, lens, vitreous, and optic neuropathy, such as keratitis, retinal hemorrhage, cataracts, and optic neuritis. Blind identification with the cortex has the following characteristics.

(1) After the visual impairment in one eye, the other eye is involved.

(2) The degree of vision loss varies, and rarely both eyes lose vision at the same time.

(3) There are many other characteristics of eye disease: symptoms such as tearing and fear of light.

(4) Ophthalmic examination can find abnormalities.

(5) vision can be improved after removing the cause.

(6) CT of the skull is mostly normal.

3. Acute retrobulbar optic neuritis

(1) Cortical blindness is a loss of vision in both eyes, while acute retrobulbar optic neuritis is usually single-eye blindness, and a few are binocular vision loss.

(2) Acute retrobulbar optic neuritis is often accompanied by pain, headache and deep dull pain in the orbit. Cortical blindness has no such symptoms.

(3) The blind pupil of the cortex is normal, and there is a reaction to light, but the pupil of the acute posterior optic neuritis is dilated, and the direct and indirect reaction to light disappears.

(4) The structure of the blind fundus of the cortex is normal, while the fundus of acute retrobulbar optic neuritis is normal in the early stage, and optic nerve atrophy remains in the late stage.

(5) CT of the cortical blind skull can show softening of the occipital cortex, and the CT of the skull is normal for acute retrobulbar optic neuritis.

4. Visual aversion

(1) No visual impairment, loss of visual significance.

(2) The object provided by vision cannot be identified, but it can be identified by using a way of feeling other than vision.

(3) Blink reflex exists.

(4) Optokinetic nystagmus exists.

Cortical blind examination

1. Binocular vision examination: completely blind.

2. Pupil photoreaction: intact.

3. Fundus examination: normal, abnormal VEP examination.

Cortical blindness treatment principle

Take appropriate treatment measures for specific causes. Western medicine generally uses corticosteroids and vasodilator drugs, but the effect is not very satisfactory. Traditional Chinese medicine uses acupuncture to treat this disease with good results.