Iris Melanoma In Dogs
Melanoma is a type of cancer that can be found in a variety of tissues throughout the body. It can also develop in the iris, which is the thin, coloured section at the front of the eye that controls pupil size. Iris melanoma is a common type of intraocular tumour in dogs, and it can spread into the surrounding tissues. Any breed of dog can develop this type of melanoma, but certain breeds, such as Cocker Spaniels, Labradors and Golden Retrievers seem to be at an increased risk of iris melanoma. Your dog's chance of developing an iris melanoma increases with their age, but it's not fully understood why dogs develop this condition.
Signs Of Iris Melanoma
Iris melanoma is fairly easy to identify. It causes brown or black spots to appear on the iris, and these spots can vary in number and size. The spots may be appear raised or seem flat and they can cause the pupil to dilate. Intraocular bleeding can also occur with iris melanoma, and this bleeding can cause a build-up of pressure in the middle eye, which can lead to pain, vision loss and coordination problems. If your dog is experiencing eye pain, they may paw at their eyes, shake their head from side to side or become lethargic.
Treating Iris Melanoma
Your vet will carry out a full eye exam to diagnose iris melanoma and a tonometer will be used to measure eye pressure. An ultrasound may also be carried out to determine whether the melanoma has spread into the surrounding eye. Bloodwork and lymph node aspiration will also be carried out in an attempt to determine whether cancerous cells are present in other parts of your dog's body.
Melanomas tend to grow if they are left untreated, so prompt treatment can save your dog's sight and even their life. Your dog's treatment plan will be based on their specific circumstances, but veterinary surgery is often required to remove the affected part of the iris. Laser surgery can be carried out without associated loss of sight, particularly in cases of early diagnosis. When iris melanoma spreads into other parts of the eye, surgical removal of the eye may be necessary. Dogs often adapt well to the loss of an eye, and your vet will provide support during their recovery.
Iris melanoma tends to have a positive outcome when diagnosed early, so if you notice dark spots around your dog's iris, or any changes to your dog's eyes, speak to your vet.