Inherited eye diseases in dogs

Cataracts are caused by a clouding of the lens within the eye, which can eventually lead to blindness. There are many different types of cataract, depending on whereabouts the clouding, also known as an “opacity”, is found. Some hereditary cataracts can begin to affect a dog younger in life, such as in Boston Terriers, whereas some are considered later-onset forms, such as in Golden Retrievers.

Collie eye anomaly/ choroidal hypoplasia (CEA/CH) causes abnormal development of the choroid - an important layer of tissue under the retina of the eye. Since the choroid layer does not develop normally from the start, this disorder can be diagnosed at a very young age. The symptoms and impact can vary greatly between affected dogs, with some not showing any signs of vision impairment, to blindness in others. Some breeds known to be affected include herding breeds such as Border Collies, Bearded Collies, and Shetland Sheepdogs.

A cataract is an “opacity”, or loss of transparency of the lens inside the eye. The opacity may be within a small area of the lens, or it may affect the whole structure. A congenital cataract is present from birth and can cause blindness in affected puppies. Miniature Schnauzers are known to be affected by this form of cataract.

Glaucoma is a painful condition caused by a build-up of pressure inside the eye. This pressure can occur if the eye isn’t able to properly drain away enough of the fluid it naturally produces. The rise in pressure (referred to as intraocular pressure) can become so high that it causes damage to other tissues within the eye, leading to permanent vision impairment and blindness. There are different types of glaucoma, which you can read more about here. Some breeds known to be affected by glaucoma include Golden Retrievers, Cocker Spaniels, and Hungarian Vizslas.

MRD is a type of eye condition where folds occur within the retina. Many dogs with MRD have no obvious symptoms and their vision appears to be unaffected. On occasions, extensive retinal dysplasia may be associated with visual defects and, rarely, blindness. Upon examination of affected dogs, retinal folds may become less obvious over time or even disappear. Breeds where MRD has been seen include Cavalier King Charles Spaniels, Rottweilers, and Golden Retrievers.

This condition, seen primarily in Cairn Terriers, is due to an abnormal build-up and spread of pigment throughout the eye. This pigment can clog the internal drainage pathways in the eye, leading to painful glaucoma and blindness.

This condition can be found from birth (congenital). It can vary from having no impact on a dog’s vision, to being severe and causing complete blindness. The Staffordshire Bull Terrier and Dobermann are breeds known to be affected by PHPV.

In affected dogs, fibres which support the lens in the eye break down, causing the lens to fall into the wrong position. This can cause rapid loss of vision, severe pain and glaucoma. Symptoms include a reddening in the eye, and loss of vision, which may be detectable from 20 months of age. Complete lens luxation typically occurs at the age of 3-8 years. Primarily terrier breeds are known to be affected by PLL, including Miniature Bull Terriers, Parson Russell Terriers and Tibetan Terriers.

PRA causes cells in the retina at the back of the eye to degenerate and die. Owners of affected dogs first notice that their dog becomes night blind, and whilst not painful, this can eventually progress to total blindness. The age at which the first signs appear varies between breeds, however, in all cases puppies are born with perfect vision and their sight begins to degenerate later in life, from around 3 years of age or later. PRA can be seen in a wide variety of breeds, including popular breeds such as Labrador Retrievers and Poodles.

This disease (previously called CPRA, or central progressive retinal atrophy) affects the retina in the eye, which may reduce a dog’s eyesight, and lead to total blindness. The disease is caused by an inherited form of vitamin E deficiency, which leads to the build-up of harmful pigment granules across the body, including in the eye. These build-ups lead to a breakdown in the cells of the retina. Thankfully, careful management through a dog’s diet can protect them from a dangerous drop in vitamin E levels. RVED has been seen in Polish Lowland Sheepdogs and Cocker Spaniels.

This condition is commonly associated with non-attachment of the retina, or complete detachment, which causes blindness. Affected puppies are often blind from birth and may have a completely white pupil. There are several different forms of the condition present in various breeds. Terrier breeds such as Sealyham Terriers and Bedlington Terriers have been found in the past to be affected by this condition.