Tools of the trade: Welch Allyn Finnoff Transilluminator


by Dr Cale Weston, Nairne Vet, SA

This transilluminator produces a very focused beam of light that we use for eye examinations. It’s such a direct fine beam that it allows us to see very small details in and around the eye.

What’s good about it

It easily picks up particles on the cornea, abnormal eyelashes, ingrown hairs, and scratches on the eye. It allows us to examine the clear structures and see through the tear film all the way to the back of the eye.

We can run a retroillumination test by looking back to the reflective tapetun and watching if the light reflects back normally. If it does, we can be confident that the clear structures of the eye are okay. 

It uses fibre optics so the light is cool and consistent. The base is a small rechargeable battery to which different heads can be attached. We frequently use the otoscope attachment to examine ear canals. It is actually a multi-use product.

The battery has plenty of life and even though we always put it back on the charger after use, it has never gone flat. Generally, the eye examinations only last a couple of minutes but I have used it continuously for over 30 minutes.

Most dogs and cats tolerate the light of the transilluminator very well. We start the test at arm’s length, well away from their face and move slowly so they are not too threatened. 

What’s not so good

The only negative is that it is handheld so it can be a bit of a juggling act during the examination. When examining a cat, the light can be positioned right next to your eyeball so you need to be alert. 

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