Vision loss

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

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Overview

Vision loss or visual 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.

Characterization of vision loss

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.

Ranges of vision loss

Various scales have been developed to describe the extent of vision and vision loss based on visual acuity.^[1] Early editions of the World Health Organization's ICD described a simple distinction between "legally sighted" and "legally blind".^[1] The ICD-9 released in 1979 introduced the smallest continuous scale which consisted of three tiers: normal vision, low vision, and blindness.^[2]

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.

Differential Diagnosis of Vision Loss

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

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).

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

Acute Pharmacotherapies

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

Surgery and Device Based Therapy

Corneal Hydrops

Corneal transplant

Retinal detachment

Surgical repair

Cataracts

Surgical removal

Temporal arteritis

Temporal biopsy

References

↑ ^1.0 ^1.1 International Council of Ophthalmology. "International Standards: Visual Standards — Aspects and Ranges of Vision Loss with Emphasis on Population Surveys." April 2002.
↑ World Health Organization. International Classification of Diseases, 9th Revision (ICD-9), World Health Organization, Geneva, 1977.

External links

AFB Senior Site Expanding possibilities for people with vision loss
CDC's "Learn the Signs. Act Early." campaign - Information for parents on early childhood development and developmental disabilities such as vision loss
Living with Vision Loss - American Foundation for the Blind
VisionAWARE - Self Help for Vision Loss Independence for adults with low vision
International Standards: "Visual Standards - Aspects and Ranges of Vision Loss" - International Council of Ophthalmology

Acknowledgements

The content on this page was first contributed by Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3]

List of contributors: