What is a cataract and what is the cause?

A cataract is an opacity of the lens inside the eye. Not all cataracts lead to significant visual loss, but if they are severe, blindness can result. As cataracts progress, the eye can become cloudy blue or grey, leading to reduced vision and, in some advanced cases, inflammation and other problems such as glaucoma.

There are many different causes of cataracts. Some are inherited (genetic) in certain breeds, but sometimes they can be secondary to other conditions such as diabetes, intra-ocular inflammation (uveitis), trauma, retinal disease, or old age. Often, the cause of cataracts is not identified (idiopathic).

How are cataracts treated?

Some minor cataracts that do not cause significant visual loss do not require treatment. Instead, careful monitoring for progression is generally advised in these cases. Cataract surgery is advised if a cataract progresses to lead to significant loss of vision. Regular monitoring is vital because if progression is noted, early surgical intervention leads to the best success rates.

Lens There is no medical treatment for cataracts, but sometimes, there is concurrent inflammation in the eye. This may require anti-inflammatory drops to prepare the eye for the operation or to prevent other potential problems that can arise if cataracts are not removed (e.g. glaucoma).

What is involved in cataract surgery?

Cataract surgery in animals is performed under general anaesthesia, and microsurgical techniques are used under an operating microscope. Cataracts are routinely removed by phacoemulsification (phacos = lens; emuls = to milk out). This operation involves using ultrasound energy introduced into the eye by a handpiece about the size of a pen. This instrument is used to break up the solid lens material into a liquid, which is then aspirated from the eye. As the entire lens can be removed in this way, the incision required to remove the cataract is very small (about 2.5mm long), leading to much better success rates than older techniques in which the entire lens was removed whole, requiring a much longer incision.

At Perth Animal Eye Hospital we use an AMO Signature phacoemulsification unit, one of the most advanced units available. As a result of this we expect a success rate of between 90 to 95% for the return of useful vision following routine phacoemulsification.

Following removal of the cataract an implant lens is generally placed into the eye. These intraocular lens implants (IOL’s) restore normal vision to the eye and are routinely placed in human eyes following removal of cataracts. However, while it is ideal to place an IOL, not all eyes are suitable for an implant and the decision as to whether or not to place an IOL is made at the time of surgery.

Surgery at Perth Animal Eye Hospital is performed as a day-patient procedure. Animals must have no food from 9 pm the night before the operation and should have nothing to eat on the morning of the operation. Diabetics should also have no breakfast and should have half their usual morning dose of insulin on the morning of the procedure. Your pet may drink freely up until the time of admission to Referral Services. In some cases, you will be asked to administer different types of eye drops at home on the day of the surgery to prepare the eyes for the operation, generally starting at 7am and continuing at 7.30 am. Your pet needs to be admitted between 8 am and 8.30am on the day of the operation and can generally come home the same afternoon between 3 and 5pm.

After the operation, eye drops will be required to be applied to the eye(s) four times a day for a month, generally then reduced to twice a day for the following month and then once a day for the third month. Most animals can then come off treatment, but in rare cases of grumbling inflammation, treatment may be required for more extended periods or even indefinitely. Animals also generally receive anti-inflammatory treatment by mouth for a month and antibiotics for 5 days.

Routine post-operative reexaminations are generally performed the next day, then a week later, a month later, and three months later. At Perth Animal Eye Hospital, routine follow-up examinations over the six months following the surgery are included in the price of the operation.

What are the risks involved in cataract surgery?

Animals require a general anaesthetic to have their cataracts removed.

While it is important to appreciate that every anaesthetic carries a risk, the risks associated with general anaesthesia are very small with modern anaesthetic agents and monitoring facilities.

Although we expect a 90% success rate, this means that around 10% of patients may still need to be successfully restored. There are many reasons why the surgery may not restore vision. Whenever surgery is performed inside the eye, the operation will cause inflammation inside the eye. Dogs’ eyes get much more inflammation following the operation than human eyes, which is why eye drops and other medications are so crucial. If an eye reacts badly to the surgery, it can get a lot of inflammation, which can lead to glaucoma (high pressure in the eye). If this does develop, it can usually be controlled by other medications. However, if the glaucoma is not able to be controlled, this can lead to blindness and, in some rare cases, even loss of the eye (just as in some unfortunate situations in humans). However, this is extremely rare and not something to panic about or dwell on, but it is vital to know beforehand that these risks exist. Glaucoma is the worst outcome for a post-operative eye. Still, other conditions can reduce the success rate, such as wound breakdown, retinal detachment, scarring and adhesions inside the eye, and clouding of the cornea. Sometimes, these situations can be resolved by a second procedure at an extra cost. Although it is essential to know these risks, most animals have good outcomes and excellent vision post-operatively.

What is the cost of the surgery and what is included and not included in the price?

At Perth Animal Eye Hospital, we believe in providing the best treatment possible for your pet. The equipment and high-quality disposables used during the operation are the same as we would have if we required this surgery. Due to the equipment and disposable costs, phacoemulsification is an expensive surgery. A final quote can only be determined after examining the eye, discussing various cost options, and planning a management strategy. Options do exist, and costs do vary depending on budget, but at Perth Animal Eye Hospital, we do not compromise on providing the highest quality outcome for your pet’s eyes. This surgery can only be done once, so it must be done with high-quality materials and using the latest technology to maximise outcomes. Lower-cost options have a lower success rate and may, in fact, put the eye itself at risk, and a poor result in the worst-case scenario can lead to the removal of the eye.

Our estimate includes the operation itself, all the medications dispensed on the day of the operation, and routine reexaminations on the day after surgery, one week, one month and three months after the surgery. As it is impossible to predict the need for other medications after the operation (such as how many eye drops will need to be dispensed, etc), the cost of medications other than those supplied on the day will incur extra expense. Consultations other than routine reexaminations within the first six months after the surgery may also incur a reexamination fee.

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