Blindness can occur in any animal. Yet we rarely think of it occurring in our ferrets. This is because we are just now becoming aware of its presence and the causes. It’s also because these wee ones do rather well without site! Sometimes, it can be hard to spot a ferret with visual impairments.

How frequent is it? I do think it’s far more common than anyone can guess. It’s not always something that jumps out at an owner or even a vet.

What are the signs of blindness?

- Fearfulness

- Extreme hesitancy to come out of cages, etc.

- Startling

- Hiding

- Running along walls or other large objects and avoiding open space

- Bumping into things

- Lots of lifting of the nose and repeated smelling

What are the causes?

- Seizures such as from insolinoma and other illnesses.

- Glaucoma (larger or protruding eye or eyes, opaque cornea, and or lesions of the retina are indicators)

- Diabetes

- Optic malignancies or interoptic neoplasms

- Brain or optic nerve injury or damage from disease

- Retinal displacement

- Macular problems

- Dislodged lenses

- Canine distemper

- Deficiencies in vitamin A or taurine can lead to retinal degeneration, as can irradiation, anemia, and toxins that have been ingested (bracken fern, for example).

- Oxygen toxicity (during anesthesia for example)

- Pigmentary keratitis (occurs when spots of pigment are deposited in the eye, eventually leading to blindness. The cause is unknown.)

- Congential things such as:

aphakia (no lens)

microphakia (small lens)

microphthalmos (decreased eye size). Ferret with very small eyes or eyes of different sizes may have these congenital defects.

Probably the most common cause of blindness in ferrets is retinal atrophy.
It was initially reported by Tom Kawaski in the Journal of Small Exotic Animal Medicine – Dr. Bruce Williams as posted on the Ferret Health List

How do we test for blindness at home and with a vet?

Testing at home can be very subjective but it will help elaborate if a ferret does have a visual problem and needs to visit a vet.

The difficult thing about testing a ferret at any given point is that the remaining senses that the ferret uses are particularly keen. So, try to test your pet without making any noise and try using things that have little or no odor. I use a series of procedures to test tracking.

First, I make sure no other ferrets are around so they don’t cue the ferret being tested. I make sure it’s a room with no other distractions or sounds. A very familiar room.

Step one: I very quietly try to wave my arms and get the ferrets attention from across the room.

Step two: I use a wide blanket and quietly wave it and without making a breeze. This action, when seen, is usually irresistible to a ferret.

Step three: I tie an odorless (well, to a human nose) a bright (red) object at the end of a string such as a ball, or another small toy. Then I dangle it about a couple of feet in front of the ferret and move it back and forth to see if the ferret notices.

Step four: I try catching the ferrets attention with the toy at several different distances. All the way up to swinging it a few inches from their face.

Step five: I tie a soft little toy to the end of a string and drag it quietly in front of them and zig zag it to see if they can follow it accurately.

Step six: I try using my hands doing the same thing. Perhaps they can’t really see objects well, but they are sensitive to shadows.

Step seven: I try to hold my hand or dark paper several inches away from their face and move it away to see if they notice the change in light.

By performing these and similar things, you should be able to get a small idea of what your ferret can and cannot see. This way you can report your findings to your vet. It’s nearly impossible to get a very accurate reading of any sorts of tests like this in the distractive veterinary office. Such information is valuable.

No matter what the results are at home, if you suspect any vision loss at all, take your ferret to the vet. The doctor can tell a surprising amount just from an eye examination. Some conditions do need immediate treatment. Furthermore, some eye conditions can indicate other serious conditions that may require treatment.

Do we need to take special care of these pets to make life easier and more enjoyable for them?

- Speak to them before picking them up, don’t sneak up on them

- Don’t move furniture around very often

- Utilize Scent mapping

- Keeping them away from risks such as stairs and water

- Make visitors aware of the handicap and advise them

- Give them lots of olfactory stimulation and make things fun. Toss them stinky daily items such as paper fast food bags, dirty clothes, etc. Tactile stimulation is good as well.

Scent Mapping and Blindness

by Sukie Crandall

As you have noticed most ferrets aren't even slowed down by blindness, so it can even be hard to notice that one is blind. Sight is not terribly important to them compared to other senses. A few aren't so fortunate, or perhaps a room gets rearranged, or the family moves and that causes navigation difficulties. If the ferret is very active that ferret might crash into things more than usual during active romping.

One of the most useful things to do when a ferret is blind is to use scent to help map the house and point out obstacles.

The mapping can be done with food flavorings like extracts of vanilla, almond, etc. but those that have alcohol in them so can damage some furniture.

What we use are essential oils. You have to be sure to use oils of things which are safely edible and only use little swipes with some on a q-tip. Avoid violet because it confuses the sense of smell (though it can be useful for helping cover smells when guests come over and violets are edible -- real violets NOT African violets which are not related. There are essential oils of fruits (the citrus ones are good and peach is downright yummy in scent), spices (vanilla and cinnamon are marvelous as are many others but we've found the ginger and cardamon to often come up short), herbs (the mints and so on), so there is a wide selection.

For each room select two different oils. Use each for their own side of the room unless the room is small. This way the back bathroom may be rose and moving out into bedroom may get you to cinnamon on the same side as the door out and vanilla on the other side, then orange for the hall where you can turn toward peach for the dining area, or...
You get the idea.

At ferret height put the individual scents on things that project like door frames, the edges of furniture and so on, and on things which may move in a room with use like dining room chairs. That way the ferret will smell them near and the bumping will be reduced or stop.

We are aware of the scents for a few days but the ferrets seem to know they are there for as long as two weeks after application. We have found that textures and noise also help a lot so besides bells on toys we will get her playing and then have piles of plastic bags or laid out bubble wrap to surprise her when we get her running after a scented bell toy suspended from a "fishing pole". We especially loves the bubble wrap and her play goes wild when she suddenly has "pop, pop, pop" going on under her feet!