Examining the eyes of ferrets

Ocular diseases in domestic ferrets are rarely reported. This article focused on the most frequent diseases of their cornea and conjunctiva and on practical techniques for accessing the eyes of Mustela putorius furo.

In most cases, physically controlling the ferret is enough to examine the eye. Chemical restraint, generally using midazolam or butorphanol, may be required if invasive diagnostic procedures are to take place or if the pet shows aggressive signals. The effects of anesthetic drugs on ocular parameters are poorly reported in literature.

If a ferret is restrained, an examination of the eye may be achieved with a Finoff transilluminator and magnification or appropriate use of the direct ophthalmoscope. This is also an excellent tool with which to examine the cornea. Schirmer tests and fluorescent stain can be used but are not as simple to conduct as in other pets. When evaluating intraocular pressure, it is important to bear in mind that the ferret’s sex and the circadian rhythm may affect the result.

In this species, conjunctivitis is usually caused by improper bedding dust and debris or associated with infectious diseases, such as canine distemper, salmonellosis, or mycobacterium.

Despite their small and well-protected eyes, the structure of a ferret’s eye is similar to other pets, making it susceptible to corneal surface trauma. Early indications of corneal ulceration include an elevated third eyelid and corneal edema. Therapeutic approaches to treat ulcers are described in the full article. Lymphoplasmacytic keratitis reports are rare – only one in a two-year old ferret that was associated with multicentric lymphoma.

Ferrets are a popular pet and their eyes can give us clues as to systemic and other diseases. Accessing them can be a challenge so an ophthalmic examination should be methodical.

Myrna, K. and Girolamo, N. Ocular Examination and Corneal Surface Disease in the Ferret. Vet Clin Exot Anim 22 (2019) 27–33. https://doi.org/10.1016/j.cvex.2018.08.004