Introduction

There are a number of diagnostic tests that can be conducted to confirm whether a cat has cataracts and, if so, to determine the cause of the condition.

Diagnosing Feline Cataracts

At the outset, your veterinarian will observe and assess your cat for any obvious signs of vision difficulty. The initial work-up will include evaluation of pupil size and symmetry and assessment of pupillary light reflexes. The veterinarian will check the “menace reflex” by moving one hand swiftly toward the cat’s face, then stopping abruptly. Another test frequently done to detect vision deficiencies is to throw a cotton ball onto the floor while watching to see if the cat follows the movement.

The intraocular pressure of the cat’s eyes will be assessed to rule out glaucoma. The veterinarian tests the pressure inside the eye using an instrument called a “tonometer.” Assuming that intraocular pressure is normal, the veterinarian normally will dilate the cat’s pupils and use a penlight or other light source to characterize the nature and extent of the cataract and to evaluate for possible concurrent uveitis. Anesthetic drops are normally applied to the eyes before these tests occur to ensure a painless examination and accurate test results.

Other tests that veterinarians commonly use to diagnose eye conditions include the Schirmer tear test and staining the eye with a fluorescein dye. These two tests are used to assess the moisture level of the eye, look for possible foreign bodies and determine whether the cornea has been damaged. Ocular ultrasonography and electroretinography are available for advanced evaluation of the retina and other eye structures. These advanced diagnostic tests are normally performed if surgery is anticipated.

Once cataracts are definitively diagnosed, blood tests typically will be recommended to rule in or out any underlying medical conditions that may have contributed to their development. A complete blood panel can identify many underlying medical conditions if present, and specialized blood tests can identify specific diseases such as feline immunodeficiency virus (FIV), feline infectious peritonitis (FIP) and the feline leukemia virus (FeLV).

If you notice any change in your cat’s eyes, schedule an appointment with your veterinarian. Many eye disorders worsen progressively if not treated in a timely manner. Prompt diagnosis and treatment can help preserve a cat’s vision and relieve pain.