Ocular melanosis has been studied extensively by Dr. Petersen-Jones’ team at Michigan State University. Ocular melanosis (OM), also known as pigmentary glaucoma, most commonly affects Cairn Terriers, but is also seen in other breeds sporadically. The condition is important because it commonly leads to glaucoma, in which the pressure within the eye (intraocular pressure) becomes elevated, the eye can be blinded permanently, and it can be very painful.

The glaucoma that develops in many Cairn Terriers with OM can be difficult to treat and often leads to blindness. Our studies are supported by the Foundation of the Cairn Terrier Club and the American Kennel Club – Canine Health Foundation.

What causes OM?

OM is inherited in the Cairn Terrier breed, with our pedigree analysis suggesting a dominant mode of inheritance. Unfortunately, we do not have a genetic test for OM, and the characteristic changes in the eyes may not be detected until middle-age, which is well after the dogs have been used for breeding. The lack of a genetic test and the appearance of the condition in middle-age makes it difficult to eradicate by selective breeding.

A main aim of our OM research is to identify the gene mutation that causes OM. We have made significant advances in this area of research, and our hope is that this will eventually enable us to develop a genetic test for the condition. Such a test could be used by breeders to select unaffected dogs for their breeding program and thus help reduce the incidence of the condition and eventually eradicate it completely.

What are the signs of OM?

Ocular melanosis affects both eyes and causes pigmented (i.e. black or brown) cells to accumulate in the eye. These appear as a thickening of part of the eye called the iris, and also lead to black spots or plaques that involve the white of the eye (the sclera).

Inside the eye, production of the pigment can eventually block the drainage pathway that is responsible for draining fluid from the eye (fluid is constantly produced in the eye and normally drains away into the blood stream, keeping the eye at a normal pressure). Interference with the normal fluid drainage causes the pressure inside the eye to increase. This can be painful, and causes damage in the eye that can result in blindness.

How is OM diagnosed?

Ocular melanosis is diagnosed by a veterinarian who may consult of refer your dog to a specialist (veterinary ophthalmologist). Careful examination of the eyes can reveal whether a dog is affected or not. The diagnosis may not be made until the dog is several years of age. The changes may first be detected in middle age. Glaucoma can develop as early as about seven years of age, but will often not occur until much later. Some dogs have mild changes, and may not develop glaucoma.

What are the treatment options for OM?

There is no cure for canine ocular melanosis. Typical treatments include anti-inflammatory and pain medications, as well as medications to reduce the fluid produced in the eyes. Additionally, surgical intervention may be recommended for advancing cases with glaucoma.

Where can I find more information and publications about OM?

Publications resulting from ocular melanosis research can be found through this link on PubMed.

This link is to a handout describing ocular melanosis.

My dog has OM. How can I be included in this study?

Thank you for your interest in our ocular melanosis study. Please start by completing this ocular melanosis information form and submitting it to us by email to: eyeresearch@msu.edu.

Additionally, samples and specimen may be submitted to our office for use in this study. Please see the specific forms below for guidelines.

Help support our research goals in OM

If you would like to contribute to our research, please consider a financial donation that will help further our research efforts in ocular melanosis.

Checks should be made payable to Michigan State University. Please be sure to include “Petersen-Jones OM Research Gift” in the memo line. Checks should be mailed to:

Development and Alumni Relations
College of Veterinary Medicine
Michigan State University
784 Wilson Road / Room G155
East Lansing, MI 48824

Donations also can be taken over the phone by calling Development and Alumni Relations at 517-353-4937. Be sure to tell them you want your gift to support “Petersen-Jones Ocular Melanosis Research.”

Thank you for your support!


Please contact us with questions at: eyeresearch@msu.edu