This type of surgery deserves a section in itself due to the fact that le-Veto has been voted No. 1 in the Middle East for being the first pet hospital in the Middle East to treat this very common complaint of all pets...

C a t a r a c t  

Our track record with this surgery has shown excellent results.

We have equipped Le Veto with the most sophisticated equipment for microscopic surgery that is made for the delicacy of the eyes only. It is fact that the cataracts are the leading cause of blindness in dogs.  

Today, cataracts are removed by a technology known as Phacoemulcification. This is the same type of surgery used to successfully treat cataracts in humans. Lasers are not involved in this procedure at all but it has become common among people who have had this surgery to refer to Phacoemulcification as laser. Le Veto is proud to claim that we do carry latest in equipment for this very delicate procedure.

	Veterinary ophthalmologists are often asked, "How well do animals see?" Visual function involves a combination of many factors, including: the field of view, depth perception (ability to judge distances), acuity (focusing ability), perception of motion, and color differentiation. All of these functions must then be integrated by the brain to produce useful vision. Although we are unable to ask our pets to read an eye chart, through comparative studies, it is possible to make some educated assumptions about their vision.
The position of the eyes within the head determines the degree of peripheral vision as well as the amount of the visual field that is seen simultaneously with both eyes. This binocular vision is necessary for judgment of distances. Dogs have eyes which are placed on the sides of the head, resulting in a visual field of 240 degrees compared with the human field of 200 degrees. The central, binocular field of vision in dogs and cats is approximately half that possessed by humans.
The eyes of dogs and cats have many of the modifications typically seen in animals which evolved as nighttime hunters. The pupil functions much as the aperture for a camera and can dilate for maximal light capturing ability in dogs and cats. In addition, there is a reflective layer under the retina called the tapetum which serves to intensify vision in dim light. The "mirror" effect of the tapetum results in the "eye shine" observed when an animal looks into a car's headlights. While dim light vision is enhanced by the tapetum, scattering of the reflected light may result in reduced acuity.
Although it is commonly believed that dogs and cats see only in black and white, recent evidence suggests that animals may have some degree of useful color vision. The perception of color is determined by the presence of cone photoreceptors within the retina. These cone cells function in bright light conditions and comprise approximately 20% of the photoreceptors in the central retina of the dog. In humans, the central retina (macula) is 100% cones. Behavioral tests in dogs suggest that they can distinguish red and blue colors but often confuse green and red.
Human vision with full color range possible because of specialized retina including cone photoreceptors and macula. Dogs and cats have vision with a very limited color spectrum. Red and blue can be distinguished but red and green appear similar. Animals rely on contrast and movement to identify objects. This type of normal vision is restored following cataract surgery with implantation of a replacement lens. Following removal of a cataract without replacement lens implantation, vision is improved but still blurry. Animal vision Before Cataract surgery.

Acuity is the ability to focus so that two objects appear as distinct entities. This is the value that is measured in people using an eye chart. In animals (and in infants) this can be measured using retinoscopy. Visual acuity in normal dogs has been estimated to be 20-40% that of humans. This means that, at 20 feet, a dog can distinguish an object that a human could see at 90 feet. Acuity is a function of the clarity of the structures of the eye (cornea, aqueous humor, lens, and vitreous) as well as the combined refractive powers to focus the image clearly on the retina. One of the most common diseases which can affect the clarity of the eye is formation of a cataract within the lens. Cataracts in dogs are most often inherited and may affect dogs at any age. As the lens becomes progressively opaque, an animal's vision deteriorates so that only light and dark perception exists. Surprisingly, animals function relatively well in familiar surroundings, even with severe vision impairment. This illustrates the ability of dogs and cats to depend heavily on their other senses, namely smell and hearing.

A cataract is a clouding of the normally clear lens of the eye.  The lens is enclosed within a clear sac (the lens capsule).  A cataract is not a film or coating on the eye, but a fogging of the contents within the lens.  When a cataract develops, partial or complete loss of vision may occur.   Clouding of the lens may affect a small portion of the lens, or the entire lens.  If the cataract progresses, the pupil, which normally appears black, may undergo noticeable color change and appear to be bluish or white. 

Not all cataracts lead to blindness. The cataract can progress slowly (over many years) or very rapidly (sometimes leading to blindness within a few days or weeks). 
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What causes cataracts?

There are many types of cataracts.  While cataracts in humans are generally associated with aging, cataracts are seen in animals of all ages, even in newborns.   In dogs, inherited cataract is a major cause of cataracts, and can cause blindness in dogs as young as 1-4 years of age.  Dogs with a genetic predisposition for cataract development include the Cocker Spaniel, Poodle, Siberian Husky, Schnauzer, Old English Sheepdog, Samoyed, Golden Retriever, Labrador Retriever, Maltese, Boston Terrier, and Yorkshire Terrier.  Other common causes for cataract formation include diabetes, aging, trauma, and secondary to retinal degeneration.
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What you should do if a cataract is suspected ...

If decreased vision or clouding of the eye is noticed by you or your veterinarian, your pet should be examined by a veterinary ophthalmologist for a comprehensive eye examination.  It is best to have your pet's eyes examined before the cataracts cause complete blindness, because then all of the intraocular structures (especially the retina) can be examined.   Once diagnosed, minor cataracts will be rechecked periodically to see if they progress, and anti-inflammatory drops may be prescribed to reduce inflammation caused by the cataract.   

If vision is impaired or if the cataracts are progressing, then cataract surgery can be performed to restore/improve vision.   Thanks to advances in medications and surgical techniques, cataract surgery is now performed routinely as outpatient surgery on thousands of veterinary patients each year.
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What is cataract-associated inflammation?

When a lens becomes cataractous, some of the lens protein becomes liquefied, and may leak through the lens capsule into the eye.  This will cause intraocular inflammation (uveitis) and is called cataract-associated intraocular inflammation (or lens-induced uveitis).  This inflammation must be treated with anti-inflammatory drops, because otherwise the inflammation can cause complications such as glaucoma, retinal detachment, or the development of intraocular adhesions.  If cataract surgery is being considered, it is especially important to keep the eyes uninflamed prior to cataract surgery, because preoperative inflammation can lower the success rate for cataract surgery. 

Even if a patient never undergoes cataract surgery, anti-inflammatory drops are usually continued long-term to reduce chances of complications that might result from the cataract-associated inflammation.
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How are cataracts removed?

Surgery is the only effective way to remove the cloudy lens from the eye.  There is no known medical or preventive treatment for cataracts.  Eye drops, ointments, pills, special diets, vitamins, or eye exercises have not been proven to dissolve or reduce a cataract.  Surgery is performed to remove the cloudy lens, and in many cases, an artificial lens is then implanted into the eye to restore normal vision. 

Surgical removal of the cataract is performed under general anesthesia by making a small (2-3 mm) incision into the eye.  A thick viscoelastic gel is injected into the anterior chamber to prevent the eye from collapsing during surgery, and to protect the inside of the cornea.  A special needle-like ultrasonic instrument is then inserted into the lens.  The needle tip vibrates at a very fast rate (about 40,000 vibrations per second), which ultrasonically fragments and removes the cloudy lens.  This surgical procedure is called "phacoemulsification" and is the same technique used to remove cataracts in people.   

During surgery, the cloudy lens is removed from the sack-like outer membrane (lens capsule).  In most cataract surgery patients, an intraocular lens implant  (commonly called an IOL) is then placed inside the emptied lens capsule to replace the eye's natural lens.  The IOL is a tiny, lightweight, clear, plastic or acrylic disc, and restores normal vision to the eye.  Unlike contact lenses that must be removed daily or periodically for cleaning, an intraocular lens implant is permanent.

In some patients, or in older animals, the lens attachments may be loose, or the lens may be too hard to be broken up with the phacoemulsification technique.  In these patients, the entire lens (including the outer lens capsule) is removed, in which case an artificial intraocular lens implant cannot be placed inside the eye.  These patients will still see after surgery, but their vision will not be as well-focused compared to patient with an intraocular lens implant.   With time (several weeks or months), most of these patients adjust well to aphakic ("without a lens") vision, and have good functional vision.

Cataracts cannot be removed with a laser. Lasers are sometimes used to improve vision by removing opacities within in the eye several weeks or months after cataract surgery, but are not used to remove the cataract itself.
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Should my pet have cataract surgery?

If your pet's quality of life is diminished due to decreased vision from cataracts, then cataract surgery can be performed to restore/improve vision.  Few veterinary surgeries are as profound or as immediately gratifying as restoring a pet's vision through cataract surgery. 

In the past, cataract surgery was often delayed until the patient was completely blind. However, we now know that cataract surgery is more successful if surgery is performed sooner rather than later, for several reasons.  First, mature (complete) cataracts are more likely to cause intraocular inflammation, which can cause vision-threatening complications before or after cataract surgery.  Second, the surgery itself is more difficult when the cataract is mature, or has been present for a long time (this causes the lens to become hardened, which makes phacoemulsification more difficult).  Third, the normally-clear outer lens capsule may become calcified when the cataract has been present for a long time.  This can make surgery more difficult, and can also cause decreased vision after cataract surgery.   However, cataract surgery can still be performed successfully on many mature cataracts.
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Is my pet a good candidate for cataract surgery?

Your pet's general health needs to be completely assessed before surgery to ensure that there are no internal problems that may interfere with a successful surgery, or that might increase the risk of general anesthesia.  A preoperative physical examination and preoperative tests will be performed by your regular veterinarian (these tests will include blood and urine analysis, and sometimes chest x-rays, EKGs, or other procedures as recommended by your veterinarian).   Age alone is not a deterrent to cataract surgery.  With the use of modern anesthetic agents, surgery is successfully performed on dogs and cats as old as 17-18 years of age.   Diabetic dogs are excellent candidates for cataract surgery, but their diabetes and any cataract-associated inflammation must be well-controlled before surgery. 

There may be reasons for vision loss other than the cataract, especially conditions affecting the retina or the brain.  An electroretinogram (ERG) is performed before surgery to ensure that good retinal function exists.   An ocular ultrasound examination is performed to ensure that the retina is not detached.  If the retina is not healthy, then cataract surgery is not performed (because the patient will not be able to see even if the cataract is removed).  Some older patients are affected with cognitive disease (canine "Alzheimer's").  If cognitive dysfunction is present, cataract surgery may not improve vision at all, because the brain cannot process and interpret visual signals properly.   

Your veterinary ophthalmologist will tell you if your pet is a good candidate for cataract surgery or not. 
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Diabetes and cataract surgery

Diabetic cats rarely develop cataracts.  However, most diabetic dogs (regardless of how well their diabetes is managed or how early the diabetes is detected) will develop diabetic cataracts and become blind, usually within 6-12 months of the onset of the diabetes.  Most diabetic dogs are excellent candidates for cataract surgery, but their diabetes and any cataract-associated inflammation must be well- controlled prior to surgery.

If you have a diabetic dog, it is important that your pet be closely monitored for development of diabetic cataracts, so that anti-inflammatory treatment can be started as soon as the cataracts start to form.  This is because diabetic dogs frequently develop rapid-onset cataracts, which can cause severe cataract-associated inflammation.

Cataract-associated inflammation must be treated with antiinflammatory medications to prevent complications (such as retinal detachment or glaucoma), and to ensure that the patient remains a candidate for cataract surgery (significant cataract-associated inflammation prior to cataract surgery is associated with a reduced success rate, any may even prevent cataract surgery from being performed).   
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Surgery on one eye versus two eyes

The decision on whether to operate on one or both eyes is yours to make. At our hospital, cataract surgery is usually performed on both eyes at the same time. Advantages of operating on both eyes at the same time include:  
    - a single surgery is less expensive
    - only a single anesthetic is required
    - if surgery is not successful in one eye, then the patient will usually still have vision in the other eye
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Can cataracts return after surgery is performed?

Once the cataract is removed, it will not "regrow."  However, in all cataract surgeries, not all of the lens cells can be removed from within the capsule.  Sometimes these lens cells will attempt to make new lens material, or will migrate across the posterior lens capsule and cause mild cloudiness and wrinkling of this capsule.  This is similar to frost covering a window, and is called a secondary cataract.  In humans, secondary cataracts can be removed by making holes in the posterior capsule with a laser.  However, intraocular lens implants usually prevent clouding of the lens capsule, so that laser treatment is rarely necessary in dogs.  Another way to prevent secondary cataracts in dogs is to make a small hole in the posterior lens capsule when cataract surgery is performed, so that the posterior capsule cannot become cloudy.
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What pre- and post-operative care is required for cataract surgery?

Before surgery, it is recommended that you train your pet to wear a cone collar, and become used to confinement.   Exercise and barking must be completely restricted for at least 3-4 weeks after surgery (excessive activity and barking increase the risk for postoperative retinal detachment and suture breakage).  Exercise restriction after surgery is best accomplished by kenneling your pet in a portable airline kennel,  or confining your pet to a single room or part of the house.  

Preoperative treatment consists of the application of anti-inflammatory eye drops, which are used once or twice a day for at least several weeks before surgery.  Four days before surgery, drops are increased to 4 times daily.  After surgery, oral medications (antibiotics and anti-inflammatory medication) are given twice daily, and eye drops are administered 4 times daily, for another 2 weeks.  Eye drops are then continued, 1-3 times daily, for 4-6 months after surgery.   The protective Elizabethan (cone) collar must be worn by the patient for about 2-3 weeks after surgery. 

In general, post surgical reevaluations are performed 1-2 days, at 1 and 4 weeks, and at 5-6 months following surgery.  Periodic reexaminations are then recommended every year or so (based on the patient's progress).  

If you are unable to perform the pre- and postoperative treatments, return for periodic reexaminations,  if your pet will not accept limited activity after cataract surgery, or permit you to apply medications to the eyes, then cataract surgery is not recommended for your pet.
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Success rates of cataract surgery

Specialized training, modern techniques, and advances in medications have greatly improved success rates in animals in the past 10 years. Fortunately, cataract surgery is usually successful, and 85-90% of patients who undergo cataract surgery regain useful vision.  
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