Veterinary Articles
Twenty-five Ophthalmic Insights
by Noelle La Croix, DVM, Dip. ACVO
Recently, a colleague asked me to list some of the basic insights into the practice of veterinary ophthalmology that I have learned over the years. The following is a non-comprehensive list (in no particular order) of some of that knowledge that I hope will aid in your treatment of ophthalmic cases. [More]
The Neurology of Lacrimation – How an Ear Infection Can Cause Dry Eye
by Noelle La Croix, DVM, Dip. ACVO
Neurogenic keratoconjunctivitis sicca (KCS or dry eye) can be a frustrating disease to treat. There are successful drugs to combat dry eye (tacrolimus and cyclosporine) but they sometimes fail in cases with a neurological basis. In this article I will review the neurology of lacrimation and the pathology of neurogenic KCS. [More]
Traumatic Proptosis
by Noelle La Croix, DVM, Dip. ACVO
A traumatic proptosis is an ophthalmic emergency which can ignite both panic and revulsion in a client. However, a systematic and sympathetic approach from a veterinarian can often calm the client and encourage a positive outcome. [More]
Ocular and Oral Disease
by Noelle La Croix, DVM, Dip. ACVO
The complex anatomy of the eye and orbit is intimately juxtaposed with that of the oral cavity. Oral disease can adversely impact ocular health in several ways. Foreign bodies and/or infectious organisms can directly traverse the oral cavity and enter the orbit. [More
Antibiotics to Treat Corneal Ulceration
by Noelle La Croix, DVM, Dip. ACVO
There are a number of antibiotics that are available to treat corneal ulceration. The appropriate antibiotic will specifically kill the opportunistic or contaminating bacteria within the corneal ulcer. [More]
Pemphigus Foliaceus
by Judy Seltzer, BVetMed, MRCVS, DACVD
Pemphigus foliaceus is an autoimmune disease where antibodies produced by an animal’s own immune system attack the bridges that hold skin cells together. The deposition of antibody in intercellular spaces causes the cells to detach from each other within the uppermost epidermal layers- this is known as acanthosis. [More]
Malassezia (Yeast) Dermatitis
by Judy Seltzer, BVetMed, MRCVS, DACVD
Malassezia dermatitis and otitis occurs most commonly in animals with allergies, endocrinopathies (hypothyroidism, Cushing’s disease), immunosuppressive diseases and other skin diseases. The most common causative organism is Malassezia pachydermatis. [More]
Fluorescein
by Noelle La Croix, DVM, Dip. ACVO
Fluorescein is a fluorescent dye first synthesized by the Nobel prize-winning chemist Albert Baeyer in 1871. It is derived from aromatic compounds (benzene and its derivatives) and contains four aromatic rings of carbon. [More]
What Is Bloat? (Gastric Dilatation and Volvulus (GDV))
by Jennifer Lang, DVM
"Bloat" is a term commonly used to describe gastric dilatation and volvulus (GDV).
When GDV occurs, a dog’s stomach becomes distended and twists on itself. As the stomach twists it cuts off escape routes (through the esophagus and small intestines) for gas, fluid, and food. Dogs are unable to vomit or belch to relieve the pressure in the stomach. As the stomach becomes progressively more distended, damage to the stomach, shock, and death can occur. [More]
The Schirmer Tear Test
by Noelle La Croix, DVM, Dip. ACVO
An examination of an animal’s eye should include a thorough history, visualization of both anterior and posterior ocular structures (via ophthalmoscopy), tonometry, fluorescein staining, and the Schirmer tear test. This article will review the purpose and relevance of the Schirmer tear test. [More]
Some Basic Principles of Tonometry
by Noelle La Croix, DVM, Dip. ACVO
The diagnostic measurement of intraocular pressure (IOP) is important in accessing ocular disease. Most practices today use an applanation tonometer (Tono-Pen Vet™ - Reichert, Inc.) that infers IOP by flattening a small section of the cornea. This article will describe some of the basic principles that underlie this instrument's use. [More]
Canine (not human) Glaucoma
by Noelle La Croix, DVM, Dip. ACVO
It can be very difficult for clients to understand their dog’s loss of vision when caused by glaucoma. Clients tend to associate ‘glaucoma’ with the disease of their affected parents or grandparents. Glaucomatous humans typically receive medications and regular ocular pressure checks, but do not usually develop complete blindness. However, canine glaucoma is quite different than human glaucoma. [More]
Canine Eye Registration Foundation (CERF) Exams
by Noelle La Croix, DVM, Dip. ACVO
Centuries of selective matings for various phenotypic traits has generated the diverse assortment of dog breeds seen today. However, this in-breeding has also greatly diminished the genetic diversity within each specific breed. In populations of low genetic diversity, recessive alleles are more likely to pair. Paired non-lethal recessives often generate phenotypes with decreased biological fitness. [More]
The Canine Optic Nerve
by Noelle La Croix, DVM, Dip. ACVO
The optic nerve is commonly referred to as a cranial nerve. However, it is actually an outpocketing of the diencephalon. Both the brain and the optic nerve are encased within the meninges. The optic nerve acts as a pathway by which ganglion cell axons transverse from the retina to the brain (lateral geniculate nucleus, superior colliculus, hypothalamus, pretectum, etc). [More]
Ocular Medications
by Noelle La Croix, DVM, Dip. ACVO
There are 3 major components in all eye drop medications: drug(s), solution (vector), and preservative(s). Eye ointments generally contain fewer preservatives than eye drops as their liquid-free (oil based) vectors greatly inhibit bacterial growth. Eye drops solutions have generally been designed to match the osmolarity and pH of the ocular surface, and to stabilize the drugs to be administered. From a veterinary standpoint, preservatives can be responsible for adverse reactions to ocular medications. [More]
"Does my dog see in black and white?"
Answers to Questions about Companion Animal Vision – Part 1
by Noelle La Croix, DVM, Dip. ACVO
The mammalian eye is a device for collecting and focusing light, for distinguishing between different wavelengths and intensities, and for converting that information into electrical impulses that are sent to the brain. Eyes evolved independently in various ecological niches creating species-specific morphologies. In general, an eye conferred a selective survival advantage to an individual, and therefore a reproductive advantage in a population. [More]
"Can my dog watch TV?"
Answers to Questions about Companion Animal Vision – Part 2
by Noelle La Croix, DVM, Dip. ACVO
In part 1 of this article, we reviewed color vision, light sensitivity and visual acuity in the dog. This article will review canine depth perception, field of view, and motion detection. I will also describe "flicker fusion" and how it relates to dogs watching television. [More]
Enucleation
by Noelle La Croix, DVM, Dip. ACVO
Enucleation refers to the surgical removal of the entire eye. This procedure is indicated for relatively few conditions that you and your client may face. One cannot underestimate the attachment of an owner to the eye of their pet. However, when necessary, enucleation can relieve suffering and prevent future maladies. [More]
Eyelid Reconstruction
by Noelle La Croix, DVM, Dip. ACVO
Eyelids protect the cornea from trauma, refresh the tear film, sweep away foreign debris, and block light during sleep. In mammals, the upper eyelid rises above the pupil allowing for vision and it reflexively closes (or blinks) to protect and lubricate the cornea. Trauma, neoplasia, and genetic disorders may necessitate the reconstruction of an animal eyelid. [More]
Antiglaucoma Medications
by Noelle La Croix, DVM, Dip. ACVO
Glaucoma is a disease of the optic nerve in which retinal ganglion cells atrophy, often resulting in blindness (Figure 1). Elevated intraocular pressure (IOP) is a major risk factor for the development of glaucoma. The key to glaucoma management is to determine its underlying cause. Different etiologies require different treatments. A veterinary ophthalmologist will explore both surgical and pharmaceutical options to reduce IOP. This article will summarize the most common antiglaucoma medications used by a veterinary ophthalmologist to preserve vision in dogs. [More]
Why Cats Are Not Little Dogs – Some Thoughts on Feline Ophthalmology
by Noelle La Croix, DVM, Dip. ACVO
Veterinarians face unique challenges when a cat with an “eye problem” arrives at their practice. The presentation, diagnosis, treatment, and underlying pathology of feline ophthalmic disorders often differ from their canine counterparts. This brief review will contrast feline and canine ophthalmology, and describe some novel features of feline ocular anatomy. [More]
Blood in the Eye. Part 1. Primary Intraocular Conditions
by Noelle La Croix, DVM, Dip. ACVO
Hemorrhage or bleeding into the anterior chamber of the eye is classified as hyphema. The pathogenesis of hyphema is diverse, but a breakdown of the blood ocular barrier (BOB) and subsequent inflammation (uveitis) is usually involved. Except in cases of severe intraocular disease, the differential diagnosis of hyphema does not differ from hemorrhage in other parts of the body (e.g.; hemoabdomen, pericardial hemorrhage). [More]
Blood in the Eye. Part 2. Secondary Systemic Conditions
by Noelle La Croix, DVM, Dip. ACVO
Hyphema is hemorrhage, or bleeding, into the anterior chamber of the eye. In the last newsletter, I discussed the main primary intraocular conditions (trauma, uveitis, cancer, and retinal detachment) which cause hyphema. This article will discuss hyphema that arises secondary to systemic disease. [More]
Ophthalmoscopy
by Noelle La Croix, DVM, Dip. ACVO
To the casual observer a pupil appears black, even though there is a direct transparent pathway from a pupil to a colorful retina. Ambient light enters an eye through its pupil at a multitude of different angles. [More]
A Review of Canine and Feline Oral Tumors
by Dan Carmichael DVM, Diplomate AVDC
The oral cavity is a common site of malignant neoplasia in both the dog and the cat. Tumors of the oral cavity can be classified as odontogenic tumors (neoplasia arising from tooth-forming tissues), non-odontogenic tumors, or non-neoplastic lesions. [More]
Ocular Herpes in Kittens
by Noelle La Croix, DVM, Dip. ACVO
The feline herpesvirus (FHV-1) was first isolated in 1958. The virus can replicate within the conjunctival epithelia, upper respiratory tract epithelia, and sensory ganglia. Neuronal infection with FHV-1 establishes lifelong latency with intermittent re-activation and viral shedding. Virus transmission is commonly associated with exposure to acutely infected cats, or recrudescing latently infected cats. Environmental contamination with FHV-1 is not considered a significant route of transmission. [More]
Genetic Testing in Veterinary Ophthalmology
by Noelle La Croix, DVM, Dip. ACVO
As discussed in an earlier article, the selective breeding of the canine has greatly diminished the genetic diversity within each specific breed. In populations of low genetic diversity, recessive alleles are more likely to pair. Paired non-lethal recessives often generate phenotypes with decreased biological fitness. [More]
Cranial Curuciate Ligament Instability: Introducing the Tibial Tuberosity Advancement
by Dr. Margret Puccio, DVM, Diplomate ACVS
Cranial cruciate ligament injuries are one of the most common causes of acute and chronic lameness in dogs and are also seen as a cause of lameness in cats. Unstabilized cranial cruciate ligament tears place the patient at risk of meniscal damage and osteoarthritis of the stifle joint. [More]
Interventional Radiology Techniques
by Dr. John Fondacaro, Diplomate ACVIM & Dr. Sean Hillock, Diplomate ACVIM
Since there is not an abundance of information about these procedures in the literature, the following general information will help you decide which patients may be possible candidates and allow you to adequately prepare owners prior to referral. [More]
Canine Bacterial Keratitis - When Ulcers Go Bad
by Dr. Noelle La Croix, DVM, Dip. ACVO
The cornea is a transparent tissue lacking pigments, blood vasculature, and keratinized epithelia. These properties are essential for vision, but also make the cornea susceptible to infection. The tear film acts as a physical barrier to microrganisms, prevents microbial growth with lysozyme and lactoferrin, and provides nutrition to the corneal epithelium. [More]
Cataract Referral
by Dr. Noelle La Croix, DVM, Dip. ACVO
A cataract is any opacification of the lens. Crystallins within lens fibers, or the lens fibers themselves, are disorganized within a cataract. Ultimately, crystallin disorder decreases transparency or light transmittance. Cortical cataracts are histologically associated with disordered, swollen, and ruptured lens fibers. [More]
Feline Dental Problems
by Dr. Daniel T. Carmichael
Dental disease is common in domestic felines. In fact, dental problems are the most common disease that we see in cats, and many dental problems are painful. The most common sign of pain in cats, however, is no sign at all. By diagnosing and rendering appropriate treatment, we can eliminate pain and afford our feline patients a better quality of life. [More]
Taking Care of your Pet's Teeth at Home
by Dr. Daniel T. Carmichael
The consequences of poor dental health go way beyond bad breath. Periodontal infection can lead to serious health concerns ranging from tooth loss to organ failure. It’s also no secret that dental problems are common in animals – studies have shown dental problems to be the most common problem in both dogs and cats, with periodontal disease at or near the top of the list. [More]
