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.)
* The term "distichiasis" is from the Greek words di and stichos, meaning "two rows".
Distichiasis is presumed to be inherited in the cavalier King Charles spaniel, according to the American College of Veterinary Ophthalmologists (ACVO).* In many cases, distichiasis can cause irritation and tearing, and corneal abrasions and ulcerations.
* See also, Ophthalmic Disease in Veterinary Medicine.
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.
Ocu-GLO Rx is a nutraceutical containing several natural antioxidants in a combination blend formulated specifically for canine eye health. Many veterinary ophthalmologists recommend this product to maintain healthy eyes. Even if your dog has not been diagnosed with a vision disorder, antioxidants contained in Ocu-GLO Rx are considered helpful in keeping dogs' eyes healthy.
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.
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.
Ophthalmic Disease in Veterinary Medicine. Charles L. Martin. Manson Publ. 2009; page 475, table 15.1. Quote: "Presumed Inherited Ocular Diseases: Table 15.1: Breed predisposition to eye disease in dogs: Cavalier King Charles Spaniel: ... Distichiasis".
Breed Predispositions to Disease in Dogs & Cats (2d Ed.). Alex Gough, Alison Thomas. 2010; Blackwell Publ. 53.
Ocular Disorders Presumed to be inherited in purebred dogs. Genetics Committee of the American College of Veterinary Ophthalmologists. Blue Book 6th Ed. 2013. pp. 241-247. Quote: "Cavalier King Charles Spaniel: Disorder: D. Distichiasis. Inheritance: Not defined."
Prevalence and heritability of distichiasis in the English Cocker spaniel. Tanja Petersen, Helle Friis Proschowsky, Tommy Hardon, Søren Nyhuus Rasch, Merete Fredholm. Canine Genetics & Epidemiology. August 2015;2:11. Quote: "Background: Canine distichiasis is a well-known cause of ocular irritation and excessive lacrimation (secretion of tears) in the dog. The term distichiasis originates from the Greek words di and stichos meaning two and rows, respectively, and as the name implies, the condition is characterized by an additional row of cilia, which erupts on the eyelid margin. Many purebred dogs are known to be predisposed to the condition, with many affected individuals within the populations. Even though the problem is widespread, the exact mode of inheritance and the heredity has not been studied extensively. However, some degree of genetic influence has been assumed, due to the high incidences within specific breeds. In the present study we have examined a cohort of English Cocker spaniels in Denmark to determine the prevalence and heritability of the disease. Results: Data from English Cocker spaniels with an ECVO eye examination registered between 2004–2013 were included in the study. The number of dogs examined during this period was 799, and the prevalence of distichiasis within this cohort was estimated at 49.31 % with a gender predisposition that females are more likely to get distichiasis than males. The correlation between the distichiasis status of the parents and their offspring revealed a significant association between the breeding combination of the parents and the occurrence of distichiasis in the offspring (p <0.0001). A relative risk (RR) ranging from 1.3 to 1.8 demonstrates that offspring of two affected parents are more likely to be affected than offspring descending from either one or two unaffected parents. The heritability was estimated to be moderate to high, i.e., 0.22 to 0.51. Conclusions: The prevalence of distichiasis in English Cocker spaniels from Denmark, examined in 2004–2013 was shown to be extremely high. The relative risk of developing the disease was 1.3 and 1.8 for offspring of one or two affected parents respectively. This together with the moderate to high heritability of the condition indicates that selective breeding could be used to reduce the incidence of distichiasis."
Distichiasis. Caryn Plummer. Clinicians Brief. March 2016;39-41. Quote: Distichiasis is the abnormal presence of cilia (eg, eyelashes) in the meibomian glands. Distichia hair follicles are found in the base of the meibomian gland, where the cilia exit through its orifice; the cilia may contact the cornea and cause irritation. The majority of dogs with distichia do not require any treatment; however, in cases associated with discomfort, therapeutic intervention should be pursued. If the hairs emerge from the conjunctival surface as ectopic cilia, therapeutic removal is usually necessary. Distichiasis is thought to be inherited, but the mechanism of transmission is unknown.