A cataract is an opacity in the lens. If the opacity is small often times a cataract will go unnoticed, however when it eﬀects the entire lens it becomes quite obvious as the gray, white opacity involves the entire pupil. When the cataract is complete this can impact vision and performance.
Cataracts can be inherited or secondary to chronic inﬂammation and trauma. Inherited cataracts are usually congenital and can be observed on a complete, dilated, new foal examination. American Saddlebreds, Morgans, Rocky Mountain horses, Quarter horses and Thoroughbreds are some of the breeds with congenital cataracts. It is important to identify the diﬀerence between inherited cataracts or cataracts secondary to inﬂammation or trauma. Only horses with inherited cataracts make a good candidate for cataract surgery.
When a complete cataract is present in a foal, cataract surgery may be possible. In order to determine if a foal is a candidate for surgery there is an extensive work up that is needed. The ﬁrst step is a complete, dilated ophthalmic examination including intraocular pressure testing. As long as there are not other abnormalities the next step is an electroretinogram. An electroretinogram is an electrical test of the back of the eye or retina. It is essential that the retina is working before pursuing cataract surgery. After the electroretinogram we perform an ocular ultrasound. This allows visualization of the back of the eye which the cataract is blocking. An ocular ultrasound will rule out any retinal detachments preoperatively.
If all of these ocular tests are normal it is essential to make sure there is not any underlying systemic disease. Your primary care veterinarian will perform complete lab work and do an ultrasound of the chest a few days before the surgery. These are the last hurdles before surgery.
After surgery the cataract patient will stay in the hospital for 1-2 weeks receiving multiple medications at least six times daily. They will be discharged on many medications to be administered three to four times daily. The frequency of the medication will slowly taper over time. Once they have fully recovered from surgery all cataract patients will need routine monitoring and stay on a topical anti-inﬂammatory life long.
If you believe your horse or foal may have cataracts and would like an evaluation please reach out to Dr. Tolar to schedule your appointment.