Cataracts

//Cataracts

Cataracts

The term “cataract” refers to any opacity in the lens of the eye that has the potential to block vision. Cataracts can be incomplete and occupy only a small portion of the lens, or can be mature, involve the entire lens, and be blinding. Most cataracts are breed or age-related or secondary to diabetes mellitus or inflammation. Common breeds affected by cataracts include Boston Terriers, Cocker Spaniels, Bichons, and Retrievers.

Before: A mature cataract in a Chihuahua. Note how the pupil appears white in color.

After: The same pet after cataract surgery. The outline of the artificial lens is visible within the pupil.

How are cataracts treated?

The only effective treatment of cataracts is surgical removal of the damaged lens. Most cataracts are removed surgically when vision impairment can be detected at home. Once cataracts are affecting vision, surgery should be performed as soon as possible to avoid greater risk of complications. Cataracts that have been present for a significant period of time that have become “hypermature” are associated with greater risks including retinal detachment, inflammation, secondary glaucoma, and longer surgical times.

Why should I pursue cataract surgery?

Early removal of cataracts and restoration of vision can provide a dramatic improvement in the quality of your pet’s life. Careful screening of patients for health issues that would increase the risk of complications of anesthesia or ocular surgery is crucial to selecting ideal patients, since surgery is not indicated in every patient. Your veterinarian and the Ophthalmology department can help you make this decision if your pet’s vision is impaired by cataracts.

Is my pet a candidate for surgery?

If you notice cloudiness in your dog or cat’s eyes or a change in the vision at home, your primary veterinarian may diagnose cataracts and refer him or her to the Hope Center Ophthalmology Department. We will then examine the lenses to determine whether the patient is a good candidate for surgery and perform two pre-operative tests to ensure that the eye is healthy behind the lens.

The first test is an electroretinogram (ERG), which determines whether the retina is functioning adequately. The second test is an ocular ultrasound to examine the structure of the eye and rule out abnormalities such as retinal detachment. As the procedure requires general anesthesia, a normal physical exam and lab tests including a chemistry panel, a complete blood count, and a urinalysis will be necessary prior to surgery and can be done by your primary veterinarian or the Hope Center.

What is involved in the surgical procedure?

After passing the pre-operative tests, your pet will be placed under general anesthesia and heart rate and rhythm, blood pressure, and respiration will be carefully monitored. The hair around the eyes will be clipped to provide a sterile surgical field for the operation. During the surgical procedure, a small incision is made in the cornea and a circular opening is created in the outer capsule of the lens to provide access to the cataract. The cataract then undergoes a process called phacoemulsification, during which an ultrasonic probe breaks the cataract into small pieces that can then be aspirated from the eye. If the lens capsule that remains in the eye appears healthy, an artificial intraocular lens (IOL) can be placed within the capsule. Most of the lenses implanted at the Hope Center are state-of-the-art foldable, injectable lenses similar to those used in human cataract patients. The eye is then closed with fine suture.

How successful is cataract surgery?

Cataract surgery is successful in 90-95% of patients. Vision is typically restored as soon as the patient has fully recovered from anesthesia. Some post-operative complications may include, but are not limited to, postoperative glaucoma , retinal detachment, infection, and intraocular scar formation (e.g., capsular fibrosis). These complications, although rare, may require additional examinations, long-term medication, or even additional surgery and could result in blindness or loss of the eye. However, your pet will be monitored carefully after surgery for all of these complications so that the eye can be treated as needed.

What is involved in post-operative care?

Your pet will most likely go home the day after surgery since the intraocular pressures must be critically monitored for the first 24 hours. He or she will be closely watched overnight by the Hope Center’s Emergency and Critical Care Department. The ophthalmologist will check for signs of inflammation or corneal ulceration and treat as needed. Then your pet will go home in an Elizabethan collar for 1-2 weeks to prevent him or her from traumatizing the eyes.

It will be necessary for you to give topical medications four times a day for the first week, and then with decreasing frequency after the first recheck. He or she will also go home on systemic, oral antibiotics and anti-inflammatory medications. A typical recheck schedule will involve appointments the week after surgery, then 3 weeks after, 2 months after, 6 months after, and finally annually. Medications and recheck regimen will vary if complications occur.

While the post-operative medications can be time-consuming, the success of cataract surgery depends heavily on owner compliance and administration of medications after surgery is complete. However, nothing will be more rewarding than knowing you were able to give your pet the gift of sight again.