Central Texas Veterinary Ophthalmology

Cataract Surgery

Cataracts and cataract surgery in dogs and cats

What is a cataract?

Any opacity of the lens of the eye is referred to as a cataract. The lens of the eye is the structure inside the eye which allows animals to focus. Opacities may involve a small area of the lens or progress to involve the entire lens structure, in which case they can cause blindness in the affected eye. In some dogs cataracts occur in only one eye – but in many cases both eyes are involved which may result in total blindness.

Most cataracts in dogs are inherited. The genes for the disease are passed on from the parents. In most cases we do not yet understand what biochemical abnormalities the cataract genes cause and cannot prevent the disease from occurring in dogs which inherit these genes. Other common causes of canine cataracts are diabetes mellitus, intraocular inflammation, and inherited retinal disease.

How can cataracts be treated?

At present there are no medications to remove cataracts. The only way to treat a dense cataract that is affecting vision is to surgically remove it from the eye. The most current technology for cataract removal (in people or animals) involves the use of phakoemulsification to remove the cataract. In this procedure an incision is made through the edge of the cornea (clear window at the front of the eye which a contact lens would sit on in a person). A hole is created in the anterior capsule of the lens to allow an ultrasonic probe to enter the lens and break up the cataract with ultrasound and then aspirate the emulsified lens contents from the eye, leaving behind only the lens capsule. Contrary to popular belief there is no practical method yet available to remove a cataract with a laser (although a laser may be used after cataract surgery for residual opacities and scarring).

How is vision affected by removing the lens?

The normal lens provides a third of the power of the eye to focus light on the retina (the majority of the focusing power of the eye is from the cornea). When a cataract is removed the lens contribution is lost. We try in most cases to correct for this at the time of surgery by replacing the animal’s cataractous lens with a synthetic lens (in the same way as with human cataract surgery). Without this correction dogs see better at a distance than they do close up. With a synthetic lens they have better near vision.

Can cataracts be successfully removed from all eyes?

Cataract surgery is most likely to be successful in eyes where no other ocular or systemic diseases are present. If the eye is inflamed (possibly due to the presence of the cataract) treatment with anti-inflammatory drugs is needed before surgery. If inflammation cannot be controlled or high pressure is present in the eye it may not be possible to remove cataracts. If retinal disease is present (degeneration or detachment of the retina) cataract surgery cannot be performed in most cases. Before cataract surgery a thorough eye examination is always performed and most eyes undergo a test of retinal function called an electroretinogram (this tests retinal function in a manner similar to the way an electrocardiogram tests the function of the heart) and sometimes also an ocular sonogram to enable us to see whether any retinal detachment is present.

How successful is cataract surgery in dogs and what complications can occur during or after cataract surgery?

Using phakoemulsification we are able to restore useful vision in most dogs. Just as with cataract surgery in people, a small percentage of dogs may have complications associated with the surgery. The main problems encountered are inflammation (uveitis), which tends to be more severe in dogs than in people and may result in scarring, which can affect vision. Some dogs may develop increased intraocular pressure (glaucoma), which can cause blindness by damaging the optic nerve. Retinal detachment is occasionally seen as a complication of cataract surgery (especially in breeds predisposed to retinal detachment regardless of surgery). Infection in the eye, which fortunately occurs infrequently, can be a major complication – even resulting in loss of the eye. Diabetic dogs are at an increased risk for some of these complications.

Obviously as with any surgery there are risks associated with general anesthesia. At CTVO we try to minimize these risks by performing blood tests and urinalysis before surgery to detect any other systemic conditions which might affect the response to anesthetics. If problems are detected we will recommend further workup before surgery. All patients are closely monitored during surgery and recovery.

Because we remove all of the contents of the lens it is not possible to again form a dense cataract. However some dogs may have growth of a thin layer of lens cells over the remaining lens capsule after surgery which gives a hazy, gray appearance to the eye. In most cases this does not significantly interfere with vision.

What treatment is needed in the recovery period after surgery?

It is very important that owners work closely with their veterinary ophthalmologist to ensure that their pet receive the best possible care after cataract surgery. After surgery the eyes are very delicate and have very fine sutures which close the incisions in the cornea. During the first few weeks several medications (usually eye drops) need to be applied up to four times daily to the operated eye(s). It is very important that these medications are applied to control inflammation and infection in the eye. Equally important is the need to have frequent eye examinations after the surgery to ensure that all is healing well and that no complications are developing. If owners note any change in the eye after surgery they should not hesitate to contact the ophthalmologists. Some dogs need medications for several months after surgery.

How much does cataract surgery cost?

Cataract treatment (workup, anesthesia, surgery) generally cost between $3300-4000. Medication costs vary depending on the length of time on medical therapy both before and after surgery.

Central Texas Veterinary Ophthalmology
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Cataract Surgery Cataracts and cataract surgery in dogs and cats What is a cataract? Any opacity of the lens of the eye is referred to as a cataract. The lens of the eye is the structure inside the eye which allows animals to focus. Opacities may involve a small area of the lens or progress to involve the entire lens structure, in which case they can cause blindness in the affected eye. In some dogs cataracts occur in only one eye – but in many cases both eyes are involved which may result in total blindness. Most cataracts in dogs are inherited. The genes for the disease are passed on from the parents. In most cases we do not yet understand what biochemical abnormalities the cataract genes cause and cannot prevent the disease from occurring in dogs which inherit these genes. Other common causes of canine cataracts are diabetes mellitus, intraocular inflammation, and inherited retinal disease. How can cataracts be treated? At present there are no medications to remove cataracts. The only way to treat a dense cataract that is affecting vision is to surgically remove it from the eye. The most current technology for cataract removal (in people or animals) involves the use of phakoemulsification to remove the cataract. In this procedure an incision is made through the edge of the cornea (clear window at the front of the eye which a contact lens would sit on in a person). A hole is created in the anterior capsule of the lens to allow an ultrasonic probe to enter the lens and break up the cataract with ultrasound and then aspirate the emulsified lens contents from the eye, leaving behind only the lens capsule. Contrary to popular belief there is no practical method yet available to remove a cataract with a laser (although a laser may be used after cataract surgery for residual opacities and scarring). How is vision affected by removing the lens? The normal lens provides a third of the power of the eye to focus light on the retina (the majority of the focusing power of the eye is from the cornea). When a cataract is removed the lens contribution is lost. We try in most cases to correct for this at the time of surgery by replacing the animal’s cataractous lens with a synthetic lens (in the same way as with human cataract surgery). Without this correction dogs see better at a distance than they do close up. With a synthetic lens they have better near vision. Can cataracts be successfully removed from all eyes? Cataract surgery is most likely to be successful in eyes where no other ocular or systemic diseases are present. If the eye is inflamed (possibly due to the presence of the cataract) treatment with anti-inflammatory drugs is needed before surgery. If inflammation cannot be controlled or high pressure is present in the eye it may not be possible to remove cataracts. If retinal disease is present (degeneration or detachment of the retina) cataract surgery cannot be performed in most cases. Before cataract surgery a thorough eye examination is always performed and most eyes undergo a test of retinal function called an electroretinogram (this tests retinal function in a manner similar to the way an electrocardiogram tests the function of the heart) and sometimes also an ocular sonogram to enable us to see whether any retinal detachment is present. How successful is cataract surgery in dogs and what complications can occur during or after cataract surgery? Using phakoemulsification we are able to restore useful vision in most dogs. Just as with cataract surgery in people, a small percentage of dogs may have complications associated with the surgery. The main problems encountered are inflammation (uveitis), which tends to be more severe in dogs than in people and may result in scarring, which can affect vision. Some dogs may develop increased intraocular pressure (glaucoma), which can cause blindness by damaging the optic nerve. Retinal detachment is occasionally seen as a complication of cataract surgery (especially in breeds predisposed to retinal detachment regardless of surgery). Infection in the eye, which fortunately occurs infrequently, can be a major complication – even resulting in loss of the eye. Diabetic dogs are at an increased risk for some of these complications. Obviously as with any surgery there are risks associated with general anesthesia. At CTVO we try to minimize these risks by performing blood tests and urinalysis before surgery to detect any other systemic conditions which might affect the response to anesthetics. If problems are detected we will recommend further workup before surgery. All patients are closely monitored during surgery and recovery. Because we remove all of the contents of the lens it is not possible to again form a dense cataract. However some dogs may have growth of a thin layer of lens cells over the remaining lens capsule after surgery which gives a hazy, gray appearance to the eye. In most cases this does not significantly interfere with vision. What treatment is needed in the recovery period after surgery? It is very important that owners work closely with their veterinary ophthalmologist to ensure that their pet receive the best possible care after cataract surgery. After surgery the eyes are very delicate and have very fine sutures which close the incisions in the cornea. During the first few weeks several medications (usually eye drops) need to be applied up to four times daily to the operated eye(s). It is very important that these medications are applied to control inflammation and infection in the eye. Equally important is the need to have frequent eye examinations after the surgery to ensure that all is healing well and that no complications are developing. If owners note any change in the eye after surgery they should not hesitate to contact the ophthalmologists. Some dogs need medications for several months after surgery. How much does cataract surgery cost? Cataract treatment (workup, anesthesia, surgery) generally cost between $3300-4000. Medication costs vary depending on the length of time on medical therapy both before and after surgery. Presurgical information for Diabetic Patients Presurgical information for Non-Diabetic Patients	Services CERF Clinics Diagnostic Procedures Electroretinography Equine Ophthalmology Ocular Ultrasonography Vision Testing Surgical Services Cataract Surgery Corneal Surgery Eyelid Surgery Glaucoma Surgery Retinal Detachment Surgery Surgical Procedures

Central Texas Veterinary Ophthalmology

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