"Retinal" refers to the retina; the retina is the innermost lining layer (located on the back surface) of the eyeball



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Retinal Detachment

Basics

OVERVIEW

  • “Retinal” refers to the retina; the retina is the innermost lining layer (located on the back surface) of the eyeball; it contains the light-sensitive rods and cones and other cells that convert images into signals and send messages to the brain, to allow for vision

  • “Retinal detachment” is the separation of the back part of the eye (retina) from the underlying, vascular part of the eyeball (known as the “choroid”); the choroid is located immediately under the retina and is part of the middle-layer of the eyeball that contains the blood vessels

Genetics

  • Depends on the cause—dogs with hereditary opacities in the normally clear lens (known as “cataracts”) or movement of the lens out of its normal location (known as “lens luxation”) may develop separation of the back part of the eye (retina) from the underlying, vascular part of the eyeball (retinal detachment)

  • Some breeds may have retinal tears or fissures and retinal detachment from primary vitreous abnormalities; the “vitreous” is the clear, gel-like material that fills the back part of the eyeball [between the lens and the retina])

Signalment/Description of Pet

Species

  • Dogs

  • Cats

Breed Predilections

  • Depend on cause

  • Terrier breeds—increased likelihood of developing primary lens luxation (movement of the lens out of its normal location), which may contribute to retinal tears or fissures and retinal detachment

  • Breeds that develop cataracts (opacities in the normally clear lens)

  • Shih tzus, Boston terriers, Italian greyhounds—appear to be susceptible to spontaneous retinal detachments, due to abnormal liquefied vitreous; the “vitreous” is the clear, gel-like material that fills the back part of the eyeball (between the lens and the retina)

  • Dogs with merle coat color—Australian shepherds, Shetland sheepdogs, harlequin Great Danes, collies

  • Breeds which may have severe abnormal development of the back part of the eye (retina; condition known as “severe retinal dysplasia”)—English springer spaniel, Labrador retriever, Bedlington terrier

  • Breeds with serous retinopathy (a disease of the retina characterized by accumulation of fluid); disease also known as “canine multifocal retinopathy”—Great Pyrenees, mastiffs, Coton de Tulear

Mean Age and Range

  • Depend on cause

  • Older pets—cataracts and generalized (systemic) diseases, such as high blood pressure (known as “hypertension”, cancer, and immune-mediated disease) are often age-related

  • Young dogs—severe abnormal development of the back part of the eye (retina; condition known as “severe retinal dysplasia”); serous retinopathy (a disease of the retina characterized by accumulation of fluid)

Signs/Observed Changes in the Pet

  • Blindness or reduced vision in affected eye

  • Dilated pupil with slow or no pupillary light reflex; light reflex may be near normal if detachment is sudden (acute); the “pupil” is the circular or elliptical opening in the center of the iris of the eye; light passes through the pupil to reach the back part of the eye (retina); the iris is the colored or pigmented part of the eye; the pupil constricts or enlarges (dilates) based on the amount of light entering the eye; the pupil constricts with bright light and enlarges in dim light—these actions are the “light reflexes of the pupil”

  • Blood vessels or a “floating membrane” (which is the retina) may be observed easily through the pupil, just behind the lens (the normally clear structure directly behind the iris that focuses light as it moves toward the back part of the eye [retina])

  • Vitreous abnormalities—common; the “vitreous” is the clear, gel-like material that fills the back part of the eyeball (between the lens and the retina)

  • Various changes in the appearance of the retina (light-sensitive lining of the back of the eye) may be noted when the veterinarian examines the back of the eye with an ophthalmoscope

  • Other signs will depend on any underlying, generalized (systemic) diseases

Causes

  • If the retinal detachment involves both eyes (known as “bilateral retinal detachment”), a generalized (systemic) problem is suggested

Degenerative

  • End-stage progressive retinal degeneration (a group of eye diseases characterized by generalized deterioration or degeneration of the retina, becoming increasingly worse over time)—may lead to formation of holes in the retina and retinal detachment

Anomalous (Abnormal Structure)

  • Collie eye anomaly (inherited abnormal development of the eye, leading to changes in various parts of the eye in collies); abnormal retina around the optic nerve (the nerve that runs from the back of the eye to the brain) may lead to retinal detachments; border collies, Australian shepherds, and other breeds in which dogs have merle coats

  • Multiple eye abnormalities—Akitas or any breed

  • Severe abnormal development of the retina (known as “retinal dysplasia”) and skeleton (known as “skeletal dysplasia”)—abnormal development of the eyes and the skeleton, characterized by dwarfism (known as “oculoskeletal dysplasia”) in Labrador retrievers and Samoyeds

  • Severe abnormal development of the retina (known as “retinal dysplasia”)—English springer spaniels and Bedlington terriers

  • Serous retinopathy (a disease of the retina characterized by accumulation of fluid); disease also known as “canine multifocal retinopathy”—Great Pyrenees, mastiffs, Coton de Tulear

Metabolic

  • Inadequate levels of thyroid hormone (known as “hypothyroidism”)

  • Increased protein in the blood leading to sludging of the blood (known as “hyperviscosity”)

  • Increased packed cell volume (PCV, a means of measuring the percentage volume of red blood cells as compared to the fluid volume of blood); hemoglobin concentration (hemoglobin is the compound in the red blood cells that carries oxygen to the tissues of the body); and red blood cell (RBC) count above the normal ranges (known as “polycythemia”)

  • Low levels of oxygen in the tissues (hypoxia), with bleeding complications

  • Dogs—generalized (systemic) high blood pressure (hypertension) due to POINTER=HYPERTENSION, SYSTEMIC_CF_H67 any cause, such as kidney failure, low levels of thyroid hormone (hypothyroidism), high levels of cholesterol in the blood (known as “hypercholesterolemia”)

  • Cats—most often caused by generalized (systemic) high blood pressure (hypertension) either as a primary condition or secondary to kidney failure or excessive levels of thyroid hormone (known as “hyperthyroidism”)

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