Vision loss

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: Visual loss

Overview

Vision loss is the absence of vision where it existed before, which can happen either acutely (i.e. abruptly) or chronically (i.e. over a long period of time). The effects of visual loss can, before the acquisition of alternative adaptations and skills, be devastating; especially when a person's vision disappears over a short period of time.

Classification

• Vision Loss may be:

• Unilateral
• Bilateral
• Transient
• Persistant
• Sudden
• Gradual
• Painless
• Painful
  

Loss of vision in one eye can quickly lead to loss in the other eye, thus rendering the patient blind.
Vision loss can be reversed, however it must be treated promptly. It can be an indication of a more serious underlying condition.

Pathophysiology

Media Opacity

Opacities of the clear refractive media of the eye such as the cornea, anterior chamber, lens, and vitreous humor may cause acute visual loss as manifested by blurry vision or reduced visual acuity. While pupillary reflexes may be affected, these conditions generally do not cause a relative afferent pupillary defect.

Causes of media opacity include corneal edema, hyphema, cataract and vitreous hemorrhage.

Retinal Disease

Retinal diseases may cause sudden visual loss. Because the retina is being affected, there is usually a concomitant relative afferent pupillary defect. Conditions that affect or destroy the retina include retinal detachment; macular disease (e.g., macular degeneration); and retinal vascular occlusions, the most important of which is central retinal artery occlusion.

Optic Nerve Disease

Diseases which affect the optic nerve may cause acute visual loss. Signs include an abnormal pupillary reflex, with an afferent pupillary defect when the optic nerve disease is unilateral.

The optic nerve can be affected by many diseases including optic neuritis, retrobulbar neuritis, papillitis, papilledema, glaucoma, ischemic optic neuropathy, and giant cell arteritis.

Hypoxia

The eye is very sensitive to restriction of its supply of oxygen. A dimming of vision (a brownout or greyout) accompanied by loss of peripheral perception may result from low blood pressure, shock, g-LOC (an aviation related problem) or simply standing up suddenly, especially if sick or otherwise infirm. Vision usually returns readily once the conditions restricting blood flow are lifted.

Visual Pathway Disorder

Visual pathway disorders are any problems that may impede the visual pathway. Rarely, acute visual loss is caused by homonymous hemianopia and, more rarely, cortical blindness.

Functional Disorder

The term functional disorder is now used where hysterical and malingering were historically used. This shift recognizes the inherent inability of the physician to identify the subjective experience of a patient (and thus whether that patient can truly see or not).

Acute Visual Loss

Acute visual loss may be dramatic in presentation, and is almost always alarming to the person experiencing the loss.

It may be caused by media opacities, retinal disease, optic nerve disease, visual pathway disorders, or functional disorders, or it may be in fact an acute discovery of chronic visual loss.

Causes

Transient vision loss (<24 hours)

• Amaurosis fugax

• Vision loss is unilateral and lasts only minutes

• Migrane

• Vision loss lasts 10-60 minutes

• Ocular ischemic syndrome (Cartoid Occlusive Disease)
• Papilledema

• Raised intracranial pressure
• Malignant hypertension

• Retinal detachment
• Sudden change in blood pressure

• Orthostatic hypotension

• Transient acute increase in thraocular pressure

• Acute Angle Closure Glaucoma
• Retro-or peribulbar hemorrhage

• Vertebrobasilar artery insufficiency

• Vision loss is bilateral and lasts minutes

• Vitreous hemorrhage
• Vitreous detachment

Vision loss > 24 hours:sudden, painless

• Exposure(Welder's flash)

• prolonged exposure to intense light/sunlight

• Ischemic optic neuropathy

• To prevent permanent loss, rule out giant cell/temporal arteritis

• Other retinal or central nervous system disease

• Occipital lobe CVA causing cortical blindness

• Optic Neuritis
• Retinal artery/vein occlusion
• Retinal detachment
• Vitreous or aqueous hemmorrhage (hyphema)

Vision loss >24 hours:gradual, painless

• Cataracts
• Cerebral Neoplasm
• Chronic retinopathy

• age related macular degeneration
• Diabetic Retinopathy

• Chronic corneal disease

• Corneal dystrophy

• Corneal Ulcer
• Open angle Glaucoma
• Optic neuropathy/atrophy

• Compressive lesion
• Toxic-metabolic cause
• Radiation

• Pseudotumor cerebri
• Refractive error
• Retitnitis pigmentosa

Vision loss >24 hours:Painful

• Acute Angle Closure Glaucoma
• Corneal hydrops

• Keratoconus

• Corneal abrasion/ulcer
• Herepes simplex/zoster
• Ocular onchocerciasis

• "River blindness"
• Onchocera volvulus worm

• Optic neuritis
• Orbital apex/superior orbital fissure/cavernous sinus syndrome
• [[Uveitis]

Diagnosis

History and Symptoms

History
include:

• Age
• Onset:
• Rate of loss
• Any specific trauma
• Headaches
• Medication
• Specific medical history
• Alcohol, drug and/or tabacco use

Physical Examination

Eyes

The examination should focus on:

• Acuity
• Blood pressure
• Color vision
• Cranial exam
• cranial nerve innervation
• Fundus
• Intraocular pressure
• Ocular media opacity
• Optic disc exam

Laboratory Findings

• ESR
• Fasting blood glucose
• HgBa1c
• PPD
• RPR
• FTR-ABS
• ACE level
• Vitamin B12
• Folate

MRI and CT

• CT/MRI of head and chest

Treatment

Medical Therapy

• Systemic Steroids can be prescribed for the following:

• Temporal arteritis
• Optic neuritis
• Pituitary apoplexy
• Herpes zoster

• Nonarteritic ischemic optic neuropathy patients

• Asprin

• Cavernous sinus thrombosis

• Antibiotics
• Anticoagulation

• Corneal hydrops

• Cycloplegic,hypertonic NaCl ointment

Corneal Hydrops

Corneal transplant

Retinal Detachment

Surgical repair

Cataracts

Surgical removal

Temporal Arteritis

Temporal biopsy

Related Chapters

• Blindness
• Eye examination
• Low vision
• Visual acuity
• Visual impairment