What is a cataract?
A cataract is a cloudy lens and, if dense, is seen as a white pupil. Do not confuse a cataract (white in the pupil) with a cloudy cornea (clear window at the front of the eye), a scar on the cornea or normal ageing changes of the lens. Cataracts can affect a portion of the lens or may involve the entire lens. Small cataracts (incomplete cataracts) may have some effect on vision in animals but if both lenses are totally affected (mature cataracts) vision will be lost.

What causes cataracts?
Any disturbance to the eye that upsets the growth of the lens fibres, can cause the lens to become cloudy. Systemic diseases (eg. Diabetes), intraocular inflammation, PRA (Progressive Retinal Atrophy), other retinopathies and trauma can all cause cataracts. Some cataracts are inherited, most however are NOT. Cataracts are common in older dogs. Total blindness caused by rapidly forming cataracts is often diagnosed in diabetic dogs.

Can cataracts be treated medically?
No! Spontaneous partial disappearance or resorption of cataracts occurs occasionally in young animals and birds. Some drug companies promote drops that dissolve cataracts. These drops are expensive and have proven to be of little benefit.

My older dog has a blue, cloudy lens. Is that a cataract?
The blue, cloudy lens you see in most old animals is not from disease, but due to the hardening of the lens with age (called Senile Nuclear Sclerosis). Owners usually report that their pet may not recognise them as quickly as they once did, has trouble following a ball or occasionally bumps into things. Some vision deficit is to be expected with very advanced ageing changes in the lens.

When is the best time to have my dog’s lenses examined?
Early examination will allow us to see whether the nerve tissue at the back of the eye (retina) is healthy. It is vital to ensure retinal function is normal if surgical removal of the lens is planned. Some diseases of the retina such as PRA will cause secondary cataracts. Dogs with retinal disease are poor candidates for surgery.

If the lens is too cloudy to view the retina, an electroretinogram (see ERG handout) and ocular ultrasound will be used to check the health of the retina prior to surgery. These procedures will need to be scheduled prior to surgery. Dogs that have a poor ERG response, or abnormal ultrasound findings are not candidates for cataract surgery.

How is surgery performed?
Surgery called phacoemulsification is performed to remove the cataract. This is the same equipment used in human cataract surgery. A small incision is made in the eye and a hole is made in the capsular bag that holds the lens. Phacoemulsification is then performed, in which a special probe ultrasonically emulsifies and removes the cataract. After the entire lens is removed, an artificial replacement lens, called an intraocular lens or IOL, is placed in the capsular bag. The eye is closed with extremely small dissolvable sutures. Because even the slightest damage to structures in the canine eye can have disastrous effects, the surgery is performed under high magnification using an operating microscope. If both eyes are affected, usually both are operated on at the same time.

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How well will my dog see after cataract surgery?
After successful cataract surgery dogs see close to normal. However, we cannot give dogs perfect vision. This is because only a handful of different IOLs are available for dogs and an exact replacement of the original lens is not possible. Furthermore, dogs have more inflammation in their eyes after surgery than humans and therefore have more scarring. This scarring does slightly decrease vision. Most owners notice a tremendous increase in their pet's vision after cataract surgery, but they can still detect certain visual deficits.

After surgery, cataracts cannot recur. However, some dogs can have decreased vision years after cataract surgery due to formation of scar tissue, glaucoma (increased pressure in the eye), or retinal detachment. In rare instances, placement of an IOL is not possible. These dogs still see better, but are more far-sighted and objects are still out of focus. The cornea does two thirds of the focusing of the eye, so vision is still present but not perfect if the lens (which does one third of the focussing) cannot be replaced.

When is the best time to perform surgery?
Cataracts can leak protein into the eye causing the eye to become seriously inflamed and sore. This is seen most often in rapid onset cataracts. The white of the eye becomes red when the eye is inflamed and you will notice a watery discharge from the eye. Prolonged inflammation of the eye prior to removal of the cataract will reduce the success rate of surgery. The inflammation may also lead to secondary glaucoma (increased pressure within the eye), which is very painful and vision threatening. Diabetic dogs have slightly higher risk of developing post operative complications. A timely decision to perform cataract surgery is important. The earlier the cataract can be removed, the better the outcome.

What if cataract surgery is not done?
Immature and mature cataracts cause a serious reactive inflammation inside the eye (Lens Induced Uveitis, or LIU) that must be medically treated, whether or not surgery is performed. Cataract surgery is an elective procedure. If surgery is not performed, lifetime anti-inflammatory eye drops are required, as well as periodic eye re-examinations. LIU leads to complications such as glaucoma or a detached retina, and LIU decreases the success rate of cataract surgery.

How successful is cataract surgery?
With new techniques and the latest technology, the success rate is high. We can expect useful vision in 90-95% of cases where cataracts are removed EARLY in their development. The longer the cataracts have been present, the greater the post operative inflammation. Subsequently, the success rate of surgery falls to about 55-65% in dogs who have had cataracts for a very long time. Despite our best efforts, remember that no surgery can be 100% successful. Some unwanted complications occasionally occur including glaucoma (increased pressure), retinal detachment, infection in the eye, cloudiness in the front of the eye and rarely, bleeding into the eye. Occasionally these complications lead to vision loss. Meticulous aftercare is required to assure the best outcome. Long-term low dose topical anti-inflammatory drops will be required after the surgery.

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What other risks are involved with cataract surgery?
General anaesthesia. Anaesthesia safety has progressed tremendously during the last 5 years. However, even healthy pets CAN DIE UNDER GENERAL ANAESTHESIA. We take anaesthesia seriously and use only the latest and safest medications. All pets are monitored extensively by our surgical staff. All pets receive electronically assisted ventilation and monitoring of their blood oxygenation, carbon dioxide levels, respiration, temperature, heart function, and blood pressure.

Special consideration.
Dogs with poor teeth and infected gums present a higher risk of short and long-term postcataract surgery complications. It is important that dental work not be scheduled near the time of cataract surgery. Some dogs may require antibiotics for a longer period than is standard after the cataract surgery.

Blood tests prior to surgery.
We recommend blood tests to determine your pet's general health profile before cataract surgery. Specifically diabetic patients and animals over 8 years of age will need to have a preanaesthetic blood test performed prior to surgery. These can be performed at your local veterinary clinic 1-2 weeks prior to surgery.

Instructions for eye medication prior to surgery.
One week prior to surgery, Prednefrin Forte or Maxidex eye drops are applied FOUR times daily into the eye(s) to be operated on. These drops should be shaken 20 times before each use. The drops may cause a stinging sensation briefly following application to the eye. If the eyes become sore or discharge excessively, stop the drops and phone the hospital. You will also have to use these drops AFTER surgery as well.

In addition, Ocuflox eye drops (topical antibiotic) are commenced 48 hours prior to surgery. One drop is applied to the eye(s) 4 x daily. These drops will be continued post operatively

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Medications after cataract surgery.
Prednefrin Forte eye drops or Maxidex eye drops are applied 3-4 x daily into the eye(s). Remember these drops may cause a temporary stinging sensation, especially Prednefrin Forte. If the eyes become sore or discharge excessively, stop the drops and phone the Hospital.

Voltaren Ophtha eye drops, an anti-inflammatory topical medication, is usually dispensed in addition to Prednefrin Forte or Maxidex. Again these are applied 3-4 x daily.

Mydriacyl eye drops are applied to the eye(s) once daily. Apply this medication at least 10 minutes after Prednefrin Forte or Maxidex eye drops. Mydriacyl is use to “exercise” the pupil and causes pupillary dilation. ALWAYS BE SURE TO WASH YOUR HANDS AFTER USE.

Topical antibiotic drops will be dispensed to be used for approximately 7 days after the surgery. These are the same antibiotics started the two days before surgery.

Oral antibiotic tablets will be dispensed for 7 days after the surgery.

Oral anti-inflammatory tablets will be dispensed for up to 14 days after the surgery. These anti-inflammatory drugs will be given to you at the time of discharge. STOP these tablets and call the clinic should your pet lose his/her appetite, develop diarrhoea or begin to vomit.

How long will my dog be on medication for?
To help prevent unwanted long term complications such as secondary glaucoma and vision loss, most dogs require topical anti-inflammatory medication for months or years after surgery. The dose frequency of medication is often only once daily. This particularly applies to diabetic dogs.

Post-operative examinations.
Your dog must return to the hospital the morning after the surgery for an examination that includes an intraocular pressure check. He/she will need to be re-examined again at 3 and 7 days, 2, 4 and 6 weeks after surgery. The first four post operative revisits are included in the cost of the surgery. Revisits after this time are charged at a reduced rate. Revisits may be scheduled more often depending on the reaction of the eye(s) to the surgery. After 3 months, eyes are checked at 6-12 month intervals, for uveitis (inflammation), increased intraocular pressure (glaucoma), and retinal detachment.

Why is Cataract surgery so expensive?
Cataract surgery fees reflect the quality and value of our advanced and specalised medical and surgical services. They reflect the degree of expertise required to treat your pet, as well as the cost of the diagnostic, therapeutic and surgical equipment utilised.

Please note that full payment for surgery is required on the day of discharge.

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