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Find information on animal health topics, written for the veterinary professional.

* This is the Veterinary Version. *

Acute Vision Loss

By Kirk N. Gelatt, VMD, DACVO, Emeritus Distinguished Professor, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida

Acute loss of vision may occur with many ophthalmic and CNS diseases, usually with abrupt onset of blindness, anisocoria, mydriasis, and loss of both direct and indirect pupillary light reflexes. Bilateral loss of vision is more common, but unilateral vision loss can occur particularly when the other eye is blind. For acute vision loss, large amounts of the retina must be involved; lesions of the optic nerve can cause blindness, because the disease process can be quite localized. The rod or cone photoreceptors may be preferentially affected initially and cause either night or day vision loss. Evaluation includes thorough ophthalmic and general physical examinations, because many systemic diseases may cause blindness. Because visual field evaluations cannot be performed in animals, subjective tests for vision are necessary and include the menace test, dazzle reflex, maze test in both light and dark illumination, electroretinography, and visual evoked potentials.

Clinical Guide for Acute Blindness in Dogs

Diagnosis

Clinical Signs

Affected Visual Pathway

Etiology

Sudden acute retinal degeneration syndrome

Acute-onset blindness, dilated pupils, ± PLRa

Outer retinal layers

Unknown; Miniature Schnauzer and Dachshund have increased risk; increased alkaline phosphatase, ALT, and cholesterol

Optic neuritis

Acute-onset blindness, both eyes affected, dilated pupils, ± PLR

Optic nerve disc, retrobulbar

Part of systemic disease (eg, canine distemper, mycosis [cryptococcosis, blastomycosis], protothecosis, granulomatous meningoencephalomyelitis), neoplasia, trauma, orbital cellulitis

Retinal detachment

Acute blindness, hemorrhage

Neurosensory retina

Systemic hypertension, multiple intraocular myeloma

Intracranial disease

Normal eyes, acute blindness ± PLR

Optic chiasm

Pituitary masses, ± paranasal masses, meningiomas, lymphosarcoma

Central blindness

Acute blindness, normal PLR

Optic tracts, occipital cortex

Cardiac arrest during anesthesia, seizures, severe head trauma

Slow vision loss

Progressive loss of vision/PLR

Retrobulbar visual tracts

Hydrocephalus, CNS neoplasia, granulomatous meningoencephalomyelitis

aPupillary light-induced reflexes

Clinical Guide for Acute Blindness in Cats

Diagnosis

Clinical Signs

Affected Visual Pathway

Etiology

Retinal detachment

Acute blindness, hemorrhage

Neurosensory retina

Systemic hypertension, intraocular

Intracranial diseases

Normal eyes, acute blindness ± PLRa

Optic chiasm

Pituitary masses, ± paranasal masses, meningiomas, lymphosarcoma

Central blindness

Acute blindness, normal PLR

Optic tracts, occipital cortex

Cardiac arrest during anesthesia, seizures, severe head trauma

Slow vision loss

Progressive loss of vision/PLR

Retrobulbar visual tracts

Hydrocephalus, CNS neoplasia

aPupillary light-induced reflexes.

Resources In This Article

* This is the Veterinary Version. *