Microphthalmia is an inherited, congenital eye disorder. It is characterized by a smaller than normal eyeball. The eyes have multiple structural defects which cause blindness or severely limited vision.
Microphthalmia with multiple structural defects occurs when mutation of the RBP4 gene prevents Vitamin A from being transported from the mothers’s liver to the placenta. SCWTCA recommends that breeding stock have the Microphthalmia DNA test. If an owner or breeder has a puppy diagnosed with Microphthalmia or any other eye disease please list the condition in the SCWT Health and Pedigree Database.
- Microphthalmia detected in the first few months of life.
- Structural defects of the eye develop before the puppy is born and may not be noticeable until the eyes open.
- One study found veterinary diagnosis was more accurate at 4 months of age than at earlier stages.
- Signs include small, recessed eyeballs and a prominent third eyelid.
- An ophthalmologist’s exam will identify specific ocular abnormalities.
- Puppies are blind or have severely limited vision.
- There is a genetic test for Microphthalmia.
- Since Microphthalmia is detected at birth, prospective pet owners do not need to require a breeder provide proof of genetic testing.
- This disease has a novel recessive mode of genetic inheritance
Testing and Treatment
- Puppies suspected to have Microphthalmia should be seen by a veterinary ophthalmologist for diagnosis and to identify specific ocular defects.
- There is no treatment for Microphthalmia. Some secondary conditions such as cataracts may require treatment.
- The gene mutation which causes Microphthalmia in Wheatens has been identified and a DNA test is available.
- For more information on how to interpret DNA test results and breeding recommendations see Benchmarks Volume 49, No. 2 pages 39-41. Link below.
Other Eye Disorders:
There are other eye disorders in Wheatens and other breeds. Regular exams by veterinary ophthalmologists of dogs being bred are recommended to identify eye abnormalities. Those eye exam results and the American College of Veterinary Ophthalmologists’ breeding recommendations can be used to help avoid potential significant hereditary eye issues. There are no other DNA tests specific to Wheaten eye disorders at this time.
Articles of Interest:
Benchmarks Article on Microphthalmia page 39-41
Microphthalmia Blame The Mother
Benchmarks Articles on Microphthalmia
Example of puppy with Microphthalmia