Multifocal Retinal Dysplasia in Dogs: Causes and Care

Multifocal Retinal Dysplasia (MRD) is a hereditary eye condition affecting the retina in dogs, potentially leading to vision impairment or even total blindness. Certain breeds are more predisposed to MRD, so the British Veterinary Association recommends annual eye testing for these breeds, especially before they are used for breeding to promote responsible ownership and reduce transmission of this condition.

Understanding Multifocal Retinal Dysplasia Types

MRD manifests in three recognised types, each varying in severity but all linked to hereditary fault in retinal development:

• Type 1: Retinal Folds or Rosettes – The mildest form, marked by retinal folds or rosettes visible in a dog's eye or eyes. These lesions may disappear as the dog matures, though in other cases, they might worsen.
• Type 2: Geographical Changes – Characterised by thinning and irregularly shaped retinal areas. This form is often associated with retinal detachment. Dogs with this type may experience partial or total lifelong vision loss.
• Type 3: Retinal Detachment – The most severe form, where the retina detaches completely. The resulting total blindness can occur abruptly, leading to distress for both dog and owner.

Studies also suggest a link between MRD and other dysplasias like hip and elbow dysplasia. Importantly, symptoms of MRD are typically present from birth.

Breeds More Susceptible to Multifocal Retinal Dysplasia

Some dog breeds have a higher predisposition to MRD. These include the Cavalier King Charles Spaniel puppies, Rough Collie puppies, and Labrador Retriever puppies. The Utonagan breed has also shown incidences, though limited to a specific line to date.

Causes and Contributing Factors

This condition is inherited but can sometimes be triggered by environmental factors during pregnancy such as exposure to toxins. Nutritional aspects, particularly Vitamin D deficiency during gestation, may contribute to development. This underlines the importance of careful breeding and prenatal care.

Diagnosing Multifocal Retinal Dysplasia

Routine eye examinations may not always detect MRD, especially mild cases. Therefore, dogs from predisposed breeds should have full eye screening conducted by a qualified ophthalmologist, using specialised tests offered by the BVA. These screenings also check for other hereditary and congenital eye disorders.

Managing and Living with MRD

Currently, there is no cure or treatment to reverse MRD. Dogs that lose their sight often adapt well over time, relying more on their heightened senses of hearing and smell. Owners can support their dogs by ensuring safe, hazard-free environments and using consistent routines to help them navigate comfortably.