Cataract surgery in the dog is a highly successful procedure that many owners have chosen for their four-legged friends to regain or improve vision. Cataracts in general and a brief discussion of the preoperative workup and surgery is presented in a prior post that you can peruse if interested titled Cataracts in the Dog. (You can find this older post if you scroll to the bottom of this page and click on Older Entries.) Removal of an opaque, cataractous lens is an elective procedure that is chosen if we feel we can improve our dog’s quality of life by returning his or her vision. This surgery is rewarding for dog, owner and doctor as it can truly bring the “puppy” back in many dogs whose lifestyle had changed with a loss of sight. Nothing beats watching the joy on our client’s faces as their dog ambles back into their arms and makes eye contact after surgery!

The technical aspects of this surgery have evolved over the years with the goal to improve the ultimate success of the procedure. These improvements involve everything from patient selection and timing, pre- and post-operative medical management, surgical technique, quality and type of lens implants, instrumentation and last but not least the science of the cataract surgery machine itself. Veterinary medicine often trails human medicine when it comes to technical advances primarily due to the financial limitations of the very expensive equipment used for diagnosis and treament of many diseases. Here at the AEC, were are proud to introduce an upgrade to the most recent technology for cataract extraction in the dog in the form of a new cataract surgery machine, the Alcon Infiniti, and this post will focus on this machine.

Our new Alcon Infiniti Vision System

Cataract removal is primarily achieved by what is called phacoemulsification. In general, a small, beveled needle is introduced into the eye through a 3mm incision. While concurrently irrigating with fluid and aspirating it out, the needle will vibrate with ultrasound power to break the cataract into small pieces that are ultimately sucked out through the tip. Very cool! As you can imagine, there are numerous factors that are involved to make this work. How fast do you introduce the fluid? How much suction do you need to suck the fluid and lens pieces out while keeping the eye inflated? How much ultrasound power do you safely use to break up the lens without disrupting the other structures? How do you create a handpiece to deliver this energy inside the eye? How do you minimize the heat and inflammation that is generated in the process? Lot’s of smart people have worked on these and many other issues to help create different machines to maximize success while miniimizing risk.

The main feature that makes the Infiniti and its Ozil handpiece better is the development of torsional or elliptical phaco. Standard phaco, used for the last 30-40 years, is in a longitudinal mode. The action of the needle is in an in-and-out motion that “jackhammers” the lens material into small pieces. The torsional movement this system features adds a side-to-side motion that shears the cataract as well. This combination creates two benefits. It reduces the heat that is created during the process which can affect inflammation and incision quality and it keeps the pieces stuck to the tip to allow faster breakdown and removal.

Other advances with the pump system help add a smoother delivery and removal of the fluid while protecting against “surge” of the fluid that disrupts the evenness of the procedure. I could go into this and other parameters in more detail here but the take home point for us and your pet is that the procedure becomes faster, easier and less traumatic with this new technology. The biggest difference between a human and a dog getting cataract surgery is that dogs generate more inflammation than people with similar ocular trauma. And inflammation after surgery is the linchpin of complication. Thus, if we can decrease our inflammation by utilizing the above upgrades we should see better success. Our pets are thus benefiting from these advances and possibly to a greater degree than people in respect to inflammation. We are excited to have this new machine in our clinic and maybe your dog will see the reason why!

This may be one of the more common cocktail party questions that veterinary ophthalmologists get asked! Not that eyes in any species are not cool, but a little exotic flavor can spice up the conversation. Fortunately for us veterinary ophthalmologists, the anatomy of the eye is very similar from species to species. There are significant changes when going from mammal to bird to fish since the anatomy is altered to maximize performance depending on the environment in which an animal lives, however, the main structures are present in most eyes. Disease states will also be different based on these living conditions and expectations of performance since these conditions are varied. Thus, understanding the species variations is important to help one in coming up with a list of differential diagnoses for a given lesion in a given species. Alas, this part is interesting to the ophthalomogist but the attentive crowd at the cocktail party may start to thin! And so, we stick with the coolest creature answer and go from there!

Fortunately, the instrumentation used to examine the dog, cat and horse will also work for the mouse, elephant and eagle. As shown in a prior posting, the slit lamp biomicroscope and the binocular indirect ophthalmoscope are mobile instruments that, if one can get close enough, will allow a good view of the eye in dry conditions. Yes, sedation is occasionally needed for uncooperative animals, but most creatures can be evaluated without much in the way of heavy restraint. Dare I say, even with angry dogs and cats, trauma to the doctor or technician is usually limited to the occasional scratch with proper positioning and respect.

At this juncture, my caseload is mostly limited to the animals that can walk, fly, swim or get carried into the clinic. Large animals, including the exotics, require a field visit which are done on a selective basis. Some of my colleagues specialize in horses or farm animals and some of us may have a relationship with a local zoo, for example, to assist in those needs. We have helped with the Norwalk Aquarium on occasion as well as with numerous wildlife rescue agencies in the area. I will admit, it spices up the day for us, too, to get a break from the dogs and cats that make up 95% of what I see. Therefore, most of our exotics come from these realms as well as second opinions from local boarded exotic specialists.

Enough chatter! Here are some pictures of some patients that have graced our practice. Some we can help and others have sustained too much damage to repair. But most are attached to someone who cares and is willing to treat them with the hope of making their life better!

Grumpy the monitor

Nile Monitor in the exam room

Grumpy above is a Nile Monitor that presented for evaluation of a hazy eye. All animals with a crystalline lens can get cataracts and Grumpy was no exception. Fortunately for him, it only affected one eye so a performance decline was not evident. As long as he can see his food and amble about his environment, cataract surgery, although a possibility in reptiles, is not needed. He was quite friendly, however, it is always nice to have a handler around to help with restraint!

Monitor normal

Monitor cataract

Sugar Glider

What is a sugar glider you ask? These cute little creatures are omnivorous gliding possums typically found in Australia. They are marsupials and get their name from there enjoyment of nectar and glide like a flying squirrel. As with many nocturnal animals, sugar gliders have large eyes to help them see in the dark. The one I saw was a pet that developed inflammation and glaucoma which is increased pressure inside the eye. This guy was very sweet, easy to examine due to his large eyes and liked to hide in a pouch the owner strapped around her neck.

Sugar glider with glaucoma

Kangaroo

Speaking of marsupials, kangaroos and their cousins are very interesting critters that ophthalmologists will see for cataracts at a very young age. Hand raised orphans fed cow’s milk become affected because of a metabolic inability to convert the galactose in the cow’s milk to lactose. This allows a product called dulcinol to accumulate in the lens which pulls fluid into it, makes the fibers swell and a complete cataract forms. The cataracts can be prevented by the use of a milk substitute used in human infants with inherited galactosemia instead of a standard cow’s milk. Cataract surgery can be performed in these species with limited success because the vitreous, the gelatinous substance between the lens and the retina, becomes opaque as well with an unknown substance. So if surgery is performed, you not only have to remove the opaque lens but the opaque vitreous as well which is rather sticky and handles like old cotton candy. Unfortunately, even if successful with those manipulations, they also have a high tendence to develop glaucoma after surgery presumably from drain obstruction. Prevention is the key here.

Kangaroo in the exam room

Kangaroo with cataracts

Cod

The Norwalk Aquarium will call me every once in a while to look at animals there that have ocular changes. Most display fish are exactly that, one of many in a tank used for education. However, survival of the fittest may still hold truth both for large tanks or small. When one cod got bilateral cataracts, the question was whether this would affect the fish to be able to adequately eat and protect itself in the tank. Lens extraction was performed in this cod (the lens was shifted or luxated out of position as well) to assess whether this surgery would positivley effect the fish itself. In addition, we were also assessing the anesthetic regimen and, if successful, would it be a consideration for other more “prized” fish in the future.

Gil the Cod cataract and lens luxation

Seals

The seals at the Norwalk Aquarium have had occasional issues associated with trauma or common risks in captive pinnipeds. Cataracts and luxated lenses are occasionally noted in captive seals and we assisted with the followup care after lens surgery was performed in the past by one of my colleagues and her team who specialize in pinniped disease (who knew, right?!). We have also assisted with management in corneal injury or degeneration in the older members. Be careful looking at these critters who can be fast and unwilling to hold still! This poor girl had a degenerate cornea we watched mother nature mend with some supportive care by their great staff to avoid surgery.

Corneal degeneration in a seal

Raptors

Birds of prey are fascinating creatures with excellent vision and beautiful ocular structures to aid them in hunting prey. Many of the wildlife rescue organizations will see, treat and release these birds if they are not critically injured. Unfortunately, trauma to the head of these birds is not uncommon, usually associated with motor vehicles, and the eye is often involved. Our role is to assess these birds to see if there is vision and if there is any reversible issue that can be improved with medication or surgery. This all factors in to the ultimate decision as to whether the animal can be released back into the wild or used as a display bird. I have seen hawks and owls primarily. We even did cataract surgery in a great horned owl after we designed an intraocular lens to use to get the visual acuity back! The hawk and owl below were not so lucky with significant damage to the left eye (hawk and owl) and central nervous system (owl) that rendered them blind.

Hawk with trauma to left eye

Barred owl with traumatic eye injury

Alas, I am starting to ramble and this digital cocktail party is moving along. I could still tell you about the giraffe, fox, gekko, rooster….hey, wait, here comes the passed hors d’oeurves. Ask me about it at the next party! Waiter!!!!