Inherited Eye Problems of the Cavalier King Charles Spaniel

• Microphthalmia with multiple ocular defects

• Distichiasis

• Corneal Dystrophy

• Exposure Keratopathy

• Macroblepharon

• Cataract

• Retinal dysplasia - folds

• Retinal dysplasia - geographic, detachments

Microphthalmia is a congenital defect resulting in a small eye. Often other eye malformations go along with it, such as cataracts.

Distichiasis is a term for abnormal eyelashes. These lashes do not curl up and outward away from the eye as do normal lashes, but direct straight down or upward into the cornea. They can be uncomfortable and cause rubbing, tearing and discomfort. Is there treatment for distichiasis? Yes, permanent removal of these lashes is possible with cryosurgery. Just plucking them out will result in rapid regrowth (1-2 weeks). With the cryo technique (freezing), the lashes are in most cases permanently removed.

Corneal dystrophy is a white - gray lesion on the cornea. It is usually inherited. It usually occurs in both eyes. The lesion is usually circular or semicircular and located in the center of the cornea. It consists of crystalline deposits in the cornea (the clear front layer of the eye).

Exposure keratopathy refers to corneal damage caused by inadequate blinking. Many anatomical factors combined produce this problem: shallow orbits, a protruding eye, a large eyelid opening (macroblepharon). The cornea will often have a brown or white film often accompanied by blood vessels. This can cause vision problems. Can this be treated? Treatment involves surgical shortening of the eyelids to reduce exposure of the cornea.

A cataract is opacity of the lens of the eye. The lens, normally perfectly clear, is located behind the colored iris, roughly in the center of the sphere of the eye. When a small part of this lens, or the entire lens, becomes opaque, this is a cataract. It can cause severe vision loss. Are cataracts always inherited? No, there are other causes of cataracts other than the inherited kind. These causes include trauma to the eye (usually a penetrating wound), nutritional deficiency, diabetes, persistent pupillary membranes*, or severe ocular inflammation. These causes of cataracts however, are much more rare than the inherited cataracts. Inherited cataracts may or may not be in both eyes. When do Cavalier King Charles Spaniels get inherited cataracts? Cataracts in this breed can appear at an early age (less than 6 months). They usually affect the entire lens, progress rapidly and cause complete blindness. Is cataract surgery available for dogs? Yes, we use the same technique that is used in people: phacoemulsification. A probe, emitting high frequency ultrasound, is placed into the lens, which dissolves it and sucks it out of the eye. Many people are under the impression that this is laser surgery. This is not laser surgery. Lasers cannot be used to remove cataracts. They can remove "aftercataracts" or membranes, which form after cataract surgery. How are cataracts inherited in the Cavalier King Charles Spaniel? Inheritance is unknown at this point. It is advised to avoid breeding any dog with cataracts, the parents of dogs with cataracts, or the siblings of dogs with cataracts. Other relatives should be bred with extreme caution.

Retinal dysplasia - folds Retinal dysplasia - geographic, detachments The retina is a thin layer in the back of the eye. It collects the light impulses and sends these messages back to the brain via the optic nerve. Retinal dysplasia refers to small folds which occur in this thin layer. When retinal dysplasia is more severe, it is manifested by severe disruption of the retinal structure and often with retinal detachments. Can this condition be treated? Occasionally laser therapy can be used to reattach the retina or discourage it from detaching, but in many cases this is not successful in preserving vision. Can these dogs be bred? Dogs with the mild form of the problem (folds only) can be bred with caution. Dogs with the more severe forms of the dysplasia, or close relatives of these dogs, should not be bred.

General Questions: Why is it ok to bred dogs with some genetic eye problems and not with others? Some inherited eye problems have many genes involved. Control of all of these genes is very complicated. A single breeding incident is unlikely to make a big difference. Most important is to breed away from these problems in a more general way. In addition, these problems are the less severe ones, ones that usually do not result in blindness or severe discomfort. With the more severe problems such as cataracts, retinal dysplasia (detachments) and PRA (progressive retinal atrophy), it is strongly recommended that these dogs NOT be bred. Getting these particular genes out of the gene pool is essential.