Distichiasis Can Damage Corneas in Cavaliers
Distichiasis is the growth of extra eyelashes (cilia) from the glands of the upper or lower eyelid. A follicle develops deep within the glands rather than on the skin surface of the eyelid. As the follicle grows, it follows the duct of the gland and grows out of the gland opening along the eyelid as a set of eyelashes. (See diagram below.)
Distichiasis is presumed to be inherited in the cavalier King Charles spaniel. In many cases, distichiasis can cause irritation and tearing, and corneal abrasions and ulcerations.
All CKCSs should be examined at least annually by a board certified veterinary ophthalmologist. They are listed on the website of the American College of Veterinary Ophthalmologists (ACVO).
Treatment usually starts with the application of ophthalmic lubricants, to protect the cornea and coat the eyelashes with an oily film. Surgical correction may remove the eyelashes and kill the hair follicles, if they are causing corneal changes. Regrowth of hairs is a common problem and may require repeated surgeries. The appearance of new follicles at new locations may also occur after surgery.
Also, cryoepilation (cryotherapy or cryosurgery) has been used by veterinary ophthalmologists to remove the distichiatic lashes without damaging the normal lashes. Cryoepilation is the application of a liquid nitrogen probe which freezes the hair follicles, which then are removed. It has been reported that with cryoepilation, up to 90% of the treated distichiatic lashes do not regrow, and repeat surgical treatment is seldom required. However, this form of ophthalmologic surgery may be very expensive -- from $1,000.00 to over $2,000.00.
The Genetics Committee of the ACVO classifies distichiasis as a "breeder option" for CKCSs. Therefore, the Canine Eye Registration Foundation (CERF) does not deny certification to cavalier King Charles spaniels which are affected with the disorder. However, the Canine Inherited Disorders Database recommends that cavalier King Charles spaniels affected with distichiasis should not be bred. At the very least, dogs both affected with the disorder should not be bred to each other. Any littermates of breeding stock having distichiasis should be taken into consideration. All cavalier breeding stock should be examined by board certified veterinary ophthalmologists to determine if the dogs are affected with distichiasis.
The Cavalier King Charles Spaniel Club, USA recommends that, prior to breeding any Cavalier, the dog have a normal rating or be within CERF "breeder options" from a screening by a board certified veterinary ophthalmologist.
The Canine Health Information Center (CHIC) is a centralized canine health database sponsored by the AKC/Canine Health Foundation (AKC/CHF) and OFA. The CHIC, working with participating parent clubs, provides a resource for breeders and owners of purebred dogs to research and maintain information on the health issues prevalent in specific breeds.
AKC's national breed clubs establish the breed specific testing protocols. Dogs complying with the breed specific testing requirements are issued CHIC numbers. The ACKCSC requires that, to qualify for CHIC certification, cavaliers must have a CERF eye examination, recommending that an initial CERF exam be performed at 8 to 12 weeks, with a follow up exam once the dog reaches 12 months, and annual exams thereafter until age 5 years, and every other year until age 9 years. However, all that is required to qualify for a CHIC certificate is that the breeding stock be examined by a veterinary ophthalmologist. It does not require that the results of the examination show no eye disorders.
Control of Canine Genetic Diseases. Padgett, G.A., Howell Book House 1998, pp. 198-199, 239.
Ocular Disorders Presumed to be Inherited in Purebred Dogs. Genetics Committee, A.C.V.O. 1999.
Guide to Congenital and Heritable Disorders in Dogs. Dodds WJ, Hall S, Inks K, A.V.A.R., Jan 2004, Section II(88).
Breed Predispositions to Disease in Dogs & Cats. Alex Gough, Alison Thomas. 2004; Blackwell Publ. 44-45.
Ophthalmic Disease in Veterinary Medicine. Martin C.L. Manson Publ. 2005.
Diseases and Surgery of the Canine Eyelid. In: Veterinary Ophthalmology, 4th ed. Stades FC, Gelatt KN. Blackwell Publishing; 2007; 563–617. Summary: Distichiasis occurs frequently in the dog and is presumed to be inherited in several breeds, although the mode of inheritance is unknown. Certain breeds are overrepresented, including the American and English Cocker Spaniel, Cavalier King Charles Spaniel, Boxer, English Bulldog, Pekingese, Shih Tzu, and Dachshunds.
Canine Inherited Disorders Database: http://www.upei.ca/~cidd/Diseases/ocular%20disorders/cilia%20disorders.htm
Breed Predispositions to Disease in Dogs & Cats (2d Ed.). Alex Gough, Alison Thomas. 2010; Blackwell Publ. 53.