The Practitioner 1, 2022

The Practitioner Published by the Florida Association of Equine Practitioners, an Equine-Exclusive Division of the FVMA

Issue 1 • 2022

THE OPHTHALMIC PREPURCHASE EXAMINATION: WHAT TO LOOK FOR AND WHEN TO BE CONCERNED ERIC T. ALEXOPOULOS, DVM CARYN E. PLUMMER, DVM, DACVO

PROMOTING EXCELLENCE SYMPOSIUM 2022

OCTOBER 6-9, 2022

SAWGRASS MARRIOTT

PONTE VEDRA BEACH, FLORIDA

The President's Line Hello fellow practitioners.

EXECUTIVE COUNCIL

RUTH-ANNE RICHTER

BSc (Hon), DVM, MS FAEP COUNCIL PAST PRESIDENT

rrichter@surgi-carecenter.com

I hope everyone has had a good summer. It’s a good time to unwind and prepare for the northern folks to arrive.

I want to take a moment to remind our Florida Association of Equine Practitioners (FAEP) members of our Membership Assistance Program (MAP), a mental well-being and counseling program, that is free for you to use – this includes free counseling sessions. I encourage everyone to use this benefit whether you feel you ‘need’ it right now or not. MAP is about total wellness and can even help you with financial planning. Take a moment to scan the QR code below and download the app!

COREY MILLER

We are very excited to announce that our equine-exclusive conference season has kicked off.

Ocala Equine Conference (OEC) 2022, which was postponed from January to July, was a fantastic meeting, and marked the conference’s exciting return after so many years away due to the COVID pandemic. It was such a wonderful time to meet many of you and see old friends again. As we look towards the autumn, we hope to see you all this October for our Promoting Excellence Symposium (PES) 2022. Our world-class conference has moved to a great new venue this year, the Sawgrass Marriott in Ponte Vedra Beach, Fla., which we feel everyone will enjoy. Register for PES 2022 by September 6 and receive exciting discounts – you can find more information about the conference in the center of this issue!

cmiller@emcocala.com

Have a great summer,

ADAM CAYOT DVM

adamcayot@hotmail.com

DVM, MS, DACT

Armon Blair, DVM FAEP Council President ANNE L. MORETTA

VMD, MS, CVSMT, CVA

maroche1@aol.com

SALLY A. L. DENOTTA

DVM, PhD, DACVIM REPRESENTATIVE TO FVMA EXECUTIVE BOARD

s.denotta@ufl.edu

JACQUELINE S. SHELLOW DVM FVMA PRESIDENT-ELECT

If anyone is struggling with mental well-being, please do not hesitate to reach out to colleagues, friends, or the FAEP (call 800.992.3862).

We launched a Membership Assistance Program (MAP), which is free for all members. MAP offers personal and professional consultation to help you be your best. For more information, email info@fvma.org or scan QR code to learn more:

jackie@shellow.com

Opinions and statements expressed in The Practitioner reflect the views of the contributors and do not represent the official policy of the Florida Association of Equine Practitioners or the Florida Veterinary Medical Association, unless so stated.

Placement of an advertisement does not represent the FAEP’s or FVMA’s endorsement of the product or service.

FAEP | 7207 MONETARY DRIVE, ORLANDO, FL 32809 | PH: 800.992.3862 | FAX: 407.240.3710 | EMAIL: INFO@FVMA.ORG | WEBSITE: WWW.FVMA.ORG

2 The Practitioner

Issue 1 • 2022

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4 The Practitioner

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Issue 1 • 2022

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THE OPHTHALMIC PREPURCHASE EXAMINATION: WHAT TO LOOK FOR AND WHEN TO BE CONCERNED ERIC T. ALEXOPOULOS | DVM CARYN E. PLUMMER | DVM, DACVO

Image courtesy of Canva

Ocular health is an important aspect of welfare for all equids, whether they are destined to be a high-performance athlete or a pasture pet. Diseases, abnormalities, and injuries to the eye can greatly impact an individual horse’s serviceability and comfort.

Therefore, knowing the health and condition of a horse’s eyes prior to purchase is one of the most significant factors in deciding whether an animal may be a sound investment. In addition to impacting an animal’s functional vision which often correlates to performance, lesions may have a significant impact on value and future medical care needs. For example, even small ocular or periocular squamous cell carcinomas, may require the expenditure of considerable amounts of money in treatment, management, and monitoring costs. Additionally, ocular lesions known or suspected to be inherited may potentially impact breeding utility and income. These highlight the importance of a thorough ophthalmic exam during any prepurchase evaluation.

on the ophthalmic portion of a pre-purchase examination (PPE), which adds a layer of complexity to the veterinarian’s reporting role. To illustrate this, a recent report of horses 15 years and older revealed that nearly 88% had minor to severe ocular abnormalities on ophthalmic examination, while owners of only about 3% of those animals reported that they knew or suspected that the horse had ocular abnormalities (Malalana et al.,2018).

Guidelines for the conduct and reporting of PPEs have been established by the American Association of Equine Practitioners (AAEP, 2009). These state that the veterinarian “should list all abnormal or undesirable findings discovered during the examination and give his or her qualified opinions as to the functional effect of these findings.” However, the veterinarian “should make no determination and express no opinions as to the suitability of the animal for the purpose intended. This issue is a business judgment that is solely the responsibility of the buyer that he or she should make on the basis of a variety of factors, only one of which is the report provided by the veterinarian.”

The veterinarian does not pass or fail a horse on PPE, instead he or she is charged with discovering and documenting existing ocular problems for the buyer so that the buyer can make an informed decision. In service to this end, the veterinarian should aim to state three things in the report: (1) whether an ocular abnormality is present, (2) if present, whether or not that abnormality will have a significant effect on functional vision and (3) whether the abnormality is likely to progress or remain static.

Figure 1: This paint gelding has a number of lesions to note. The irregular wound along the middle third of the lower eyelid margin is an SCC, as is the raised vascular lesion in the ventromedial perilimbal cornea. This corneal SCC could have been easily missed if the third eyelid was not manipulated to allow inspection of the medial limbus.

Additionally, there is an area of active keratitis in the ventrotemporal peripheral cornea that was the result of irritation from the eyelid lesion and disruption of normal tear film distribution in this region.

Image courtesy of Dr. Caryn E. Plummer.

Ocular lesions are very common in horses, but they are not always easily recognized by the passive observer. In some instances, they can be subtle; in others, the lesion may be significant, but the animal may have adapted and does not exhibit visual behavior demonstrative of the abnormality. In fact, some sellers may not be aware of pre-existing abnormalities or anomalies observed

The blunt statement of these objectives belies the fraught nature of the assessment. Given that there is not currently an acute understanding of the higher visual function in the horse, nor is there a standardized means of objectively assessing vision in the horse, making a determination of how well a horse sees is not possible. While it is possible to determine that an eye is blind, it is inappropriate to make any quantitative or subjective statements about the degree of visual function or impairment that an animal may be experiencing or its potential utility (i.e. “the horse has 75% vision” or “this animal should only be ridden by an experienced rider in a well-lit arena.”) The most that can be said from examining the eye is that there is an abnormality or disease present which is damaging eye function, that a visual deficit is or is not present, and that it is either a major problem or a minor problem and is, on balance of probability, of little consequence. This can be frustrating to buyers who come with unrealistic expectations for ironclad pronouncements and predictions.

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Tools of the Trade The mainstay equipment necessary include a focused bright white light source, such as a Finoff transilluminator or a highquality penlight or head lamp, some form of magnification (e.g. jeweler’s loupes or Optivisor), a direct ophthalmoscope and a camera (Dwyer, 2012; Dwyer, 2017; Matthews, 2016). While a slit lamp biomicroscope facilitates the adnexal and anterior segment examination tremendously and will be used routinely by the veterinary ophthalmologist, they are not requisite for the routine ophthalmic pre-purchase examination. Indirect ophthalmoscopy with a 14D to 20D or 2.2 PanRetinal condensing lens complements direct ophthalmoscopy but is not necessary as long as the examiner takes care to examine the complete fundus with the direct ophthalmoscope, a process that is more time consuming if diligently undertaken. Ideally, a tonometer would be available to measure intraocular pressure, data which can support or confirm some clinical suspicions.

Additional diagnostic equipment (ocular vital stains, topical anesthetic agents, culture swaps, cytology brushes and glass slides, etc.) should be available if the examination findings warrant further investigation or confirmation.

position and angulation of the upper eyelashes. The lashes of the upper eyelid should be perpendicular to the corneal surface in a comfortable eye. A downward direction (lashed positioned on the vertical rather than the horizontal, relative to the fellow eye) may be a subtle indication of discomfort or of changes to the contents of the orbit.

Neuro-ophthalmic Assessment Prior to sedation, basic neurologic testing is performed. The pupils should be assessed for size, symmetry, and mobility. This is easily accomplished with a transilluminator directed at the center of the forehead from a distance of about six feet. It is not unusual to observe anisocoria in horses with asymmetric iris heterochromia, but this should be noted regardless. Pupillary light reflex (PLR) testing using a bright light source is then performed. Vertical iris movement and excursion are much greater than horizontal. The consensual response is less drastic

General Observation The ophthalmic PPE should proceed in the same way as a routine ophthalmic examination. The initial exam should take place prior to sedation and in a well-lit, quiet area away from distractions. Before placing hands on the animal, an assessment of it in motion is performed. The horse should be observed during the moving/riding portion of the exam for how they navigate their environment and obstacles, in both dim and lit settings. Attention should be paid to how they handle the transition between different areas of illumination along with their reaction to objects. Does the animal walk into the barrel in the dark environment but easily avoid it in the light? Are they resistant to turning in one direction versus the other? Does the head carriage change in certain circumstances or changes in lighting? Naturally, external factors such as weather at time of exam, training level of the horse, and temperament can also affect this portion of the exam. These factors should be detailed in the pre-purchase report.

External symmetry is assessed at this early stage of the examination. The examiner should stand in front of the horse and evaluate facial, ocular, adnexal, and orbital symmetry in a well-lit environment. The orbit and surrounding tissues should be palpated for any obvious abnormalities or instabilities.

Ocular comfort can be assessed by position of the eyelashes, position of the globe, ocular discharge, blink rate, and degree of blepharospasm. Particular attention should be paid to the

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Figure 2: A) Active keratitis evidenced by vascular invasion and corneal edema. B) Healing corneal ulcer. Note the difference in the color and character of the corneal opacity. There is receding vascularization, fibrosis, and quiet globe interior.

Image courtesy of Dr. Caryn E. Plummer.

Issue 1 • 2022

than the direct and can be difficult to evaluate given the positioning of the equine globes without the help of an assistant observer. Abnormal PLRs may be useful in localizing lesions within the visual pathway.

The dazzle reflex, a subcortical reflex, is assessed next. A bright light source is directed at each eye with the normal response being a blink. This tests the integrity of the visual pathway but is not a test of vision. It is particularly useful if pupil mobility cannot be observed directly due to synechiae or corneal opacity.

The menace response, a learned protective response, is a crude assessment of vision (yes or no). It is then tested by making a “threatening” hand movement towards each eye, which should result in a blink. Care must be taken to avoid pushing air towards the cornea, which can trigger the corneal reflex, a sensory response indicating functional trigeminal innervation of the corneas or eyelids. The palpebral reflex should be evaluated next, which involves gentle palpation at the medial and lateral canthus of each eye, a complete blink should ensue following palpation at either site. If an incomplete blink is noted, or no response (at either or both palpation sites), this should be noted and may indicate a facial nerve or trigeminal nerve deficit.

Timing — To Dilate or Not To Dilate?

There exists no consensus about pharmacologic dilation during the PPE, however, mydriasis is required for a complete exam of the lens and posterior segment. While the decision to dilate is the prerogative of the examining veterinarian, it must be recognized that ophthalmoscopy through a non-dilated pupil will restrict access to more than half of the fundus and while lesions in the peripheral fundus are less common than those in the peripapillary region, they will be missed if the pupil is not dilated. Response to a mydriatic agent also tests the range of iris mobility and checks for the presence of synechiae that might not be apparent when the pupil is constricted.

Prior to dilation, the examiner should complete the neuroophthalmic assessment and perform an initial inspection of the iris and pupil, paying attention to size, shape, contour, presence of defects, mass lesions, or cysts. Full mydriasis will usually take 20 minutes to achieve. The short-acting mydriatic agent tropicamide 1% is most commonly employed. Its effects generally last for three to four hours in horses with brown irides, shorter in blue eyes (Gelatt et al., 1995). Dilation should be started only after the riding/moving portion of the PPE. Once the movement portion is complete, dilation can be initiated right before the standing portion of the physical exam and be progressing as the examiner performs the rest of the physical examination as well as hoof and flexion testing and radiographs, if indicated. If the pupil cannot be dilated because the horse is

competing or the owner does not allow it, this should be stated clearly on the PPE report.

Some examiners will attempt to overcome physiologic miosis by placing the animal in a dark stall and reducing the intensity of the light used for the examination. However, this approach does not usually allow for adequate illumination for a proper examination, resulting in missed or inadequately described and assessed lesions, particularly those in the periphery of the posterior segment. Additionally, the pupillary constriction that results during the examination, even with reduced light intensity, usually results in increasing frustration for the examiner and waning patience of the horse. The quality of the examination is compromised by the attempt to save a few minutes of time.

Sedation and Regional Nerve Blocks Following the neuro-ophthalmic evaluation, the horse may be sedated to allow for complete ophthalmic examination. While not necessary in every animal, sedation is highly recommended and will provide the best circumstances for recognition and documentation of any and all ocular lesions. Short-acting sedatives like xylazine or detomidine are routinely used for ophthalmic examinations because of the rapid tranquilization without excitation and the steady low head position without movement that is achieved (Dwyer, 2012).

Following adequate sedation, some horses may be amenable to complete ocular exam, however, most will require regional nerve blocks to facilitate the examination. The orbicularis oculi muscle, responsible for eyelid closure, is very strong in the horse.

It is innervated by the auriculopalpebral nerve, a branch of the facial nerve, it emerges just caudal to the caudal border of the condyle of the mandible. Branches then course rostrally and dorsally to their destinations. The nerve may be blocked at any point between the origin of the auriculopalpebral nerve and the palpebral branch (Rubin, 1964). Effective akinesia will result in ptosis and a narrowed palpebral fissure, with effects typically lasting between 45-60 minutes when lidocaine is used. If samples are to be taken from the cornea or adnexal structures, sensory block of the eyelids may be helpful. A frontal nerve block will desensitize the medial canthal region and the medial two-thirds of the upper eyelid. Line blocks of the lateral canthus and lower eyelid will achieve sensory blockage of those respective areas. Corneal anesthesia can be achieved with a topical anesthetic such as proparacaine, tetracaine, or lidocaine.

Ophthalmic Examination A systematic approach should be taken for examination. An external to internal, anterior to posterior exam is recommended.

The initial inspection of the adnexal structures should be

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@thefvma | The Practitioner 9

performed in a well-lit environment and with an adjunctive light source. The periocular tissues, eyelids, conjunctiva, and third eyelid should be examined for position, mobility, and integrity.

Examination of the eyelids should include both assessment of function and critical examination for abnormalities (neoplasia, inflammation, previous wounds, structural defects or conformational abnormalities, etc.). The conjunctiva should be similarly examined. Assessment of the third eyelid is easily achieved by gentle retropulsion of the eye, through the upper lid, allowing passive elevation of the third eyelid. Abnormalities, such as previous wounds to the lids should be critically inspected for their effect on complete closure of the lids. With incomplete closure, chronic corneal exposure can ensue. Trichiasis, or hairs deviated toward and contacting the cornea, may be a source of chronic irritation. Masses should be inspected (visually and via palpation) for their extension. Small, superficial eyelid masses are typically much more easily and affordably treated than one that extends down towards the orbital rim. Small ulcerative wounds on the eyelids warrant further investigation, particularly if they occur in an animal with minimal periocular pigmentation or blue eyes, as they may be early manifestations of squamous cell carcinoma (SCC). Horses with blue or heterochromic irides are more likely to develop ocular and periocular SCC than horses with brown irides, but are not more likely to have adnexal, corneal, or intraocular disease or to be presented for evaluation of ophthalmic disease (Bergstrom et al., 2014).

The nasolacrimal system can be inspected via direct visualization of the upper and lower lacrimal puncta, located approximately 1 cm lateral to the medial canthus on the upper and lower lid respectively. Additionally, the lacrimal caruncle, located at the medial canthus can also be easily visualized, and can be an area commonly affected by disease (neoplasia, inflammation, parasitic granulomas, etc.). Assessment of patency is not typically performed during a PPE unless there is evidence of obstruction, however corneal fluorescein staining that results in ipsilateral nasal puncta fluorescein discharge, indicates an at least partially patent duct. Signs of a potentially occluded duct could include ipsilateral epiphora, swelling at one or both puncta, and mucoid or purulent discharge.

Examination of the globe should be performed in a dark room or stall. If this is not possible given the environment, and this portion of the PPE cannot be re-scheduled, a comment on the written report should be made about the setting.

Dark conditions are essential to performing a thorough and appropriate ophthalmic PPE. The corneal surface should be evaluated next, with both diffuse and focal illumination and magnification. Light directed across the cornea will highlight corneal opacities against the dark background of the iris. The

10 The Practitioner

corneal surface should be smooth and the cornea should be completely transparent. Determination of opacity location can be challenging without magnification, but an ophthalmoscope on the slit beam setting can be used to approximate opacity depth (i.e. superficial vs mid-stromal vs deep vs full thickness).

Any opacities should be described in as much detail as possible on the report, including notations of size, location, color, and depth. Active lesions (compared to scars) typically, but not always, result in additional clinical signs, such as corneal vascularization, corneal edema, corneal cellular infiltrate, and in some instances, blepharospasm and evidence of secondary anterior uveitis. A fibrotic scar will be expected to remain static or even regress over time, but the disposition of an active keratitis can be hard to predict.

Figure 3: Active and chronic panuveitis in an Appaloosa. Note the conjunctival hyperemia, mild diffuse corneal edema, hazy media and green hue in the posterior segment suggestive of vitritis.

Image courtesy of Dr. Caryn E. Plummer.

The anterior chamber is similarly evaluated for overall clarity.

With a thin beam or a small circular or square beam of light directed at a 45-degree angle, the anterior chamber depth and clarity can be inspected. The darker the ambient environment, the more easily aqueous flare can be assessed, though low levels of inflammation may still be difficult to assess without specialized equipment. Additional, concerning findings include hyphema, hypopyon, fibrin, masses, and a shallow or deep (compared to the fellow eye) chamber. The iris is similarly examined for any obvious scars, synechiae, masses, or cysts. Corpora nigra cysts are benign expansions of uveal epithelium. They may or may not be a significant finding. Most horses are unbothered by them and their discovery is incidental, but some individuals will exhibit behavioral abnormalities as a consequence of their presence. Equine recurrent uveitis (ERU), a chronic immune-

Issue 1 • 2022

mediated intraocular inflammatory condition, is the leading cause of blindness worldwide in horses. Its prevalence ranges from 2-25% in American horses with up to 40% of certain breeds or populations in certain regions affected (Gerding et al., 2016; Sandmeyer et al., 2020). This condition is one of the reasons a thorough ophthalmic examination as part of the complete PPE is so important. While a single bout of intraocular inflammation does not ERU make, evidence of chronicity or multiple clinical signs consistent with inflammation should raise the concern. Miosis is the hallmark of active uveitis. More than three clinical signs of uveitis, especially if there are color changes to the iris (hyperpigmentation or neovascularization), dyscoria, synechiae, corpora nigra atrophy, pigment dispersal, cataract, or chorioretinal scarring, suggests that inflammation has been previously and likely, persistently present. Afterthe-fact determination of the etiology of post-inflammatory abnormalities can be challenging, especially when a history is not available. That said, blunt ocular trauma (BOT) has a characteristic pattern of ocular signs that can be helpful in differentiating these cases from non-traumatic uveitis cases.

Corpora nigra avulsion or iridodialysis (iris separated from the iridocorneal angle and the ciliary body at its base) in combination with both anterior and posterior cataracts may be expected following BOT (Charnock et al., 2022).

The iridocorneal angle can be directly visualized in the horse in the medial and temporal quadrants adjacent to the corneal limbus; a normal angle is open with clearly visible pectinate ligament forming a mesh-like sieve. If the fine detail of the pectinate ligament is not appreciable or this region appears homogenously fibrotic, this raises concern for previous episodes of uveitis and the potential predisposition for glaucoma.

The lens is evaluated next via transillumination (direct focal illumination) and then retroillumination. Transillumination is performed similarly to corneal and anterior chamber evaluation with the light source directed at a 45-degree angle to the lens, and directly observing the lens. Retroillumination, using light reflection off the choroid (tapetum in most cases) to assess the lens, is performed by positioning the light source in a fixed position at the observer’s temple. Initially the light source should be at an arm’s length from the eye, a bright tapetal reflection is obtained and then the light source is moved toward the globe to bring lens structures into focus. This technique enhances detection of opacities of the vitreous, lens, anterior chamber, and cornea as they reflect, refract, or obstruct the returning light.

Nuclear sclerosis (NS), a normal aging change due to increased lens fiber density, can be seen with either technique. All horses greater than 15 years of age have NS which is observed as a smooth, homogenous dense center that does not impair light transmission.

Any opacity of the lens is a cataract, which consists of abnormal lens fibers. Cataracts can have many underlying etiologies, including genetic causes, metabolic derangements, or developmental anomalies, but are most commonly secondary to uveitis (immune-mediated or traumatic) in adult horses.

Signalment (and history, if available) are helpful in ferreting out potential underlying causes. Cataracts in foals and young adults may be congenital or developmental and may or may not progress. A great many do not progress, but making this statement confidently is unwise. Buyers should be advised of the uncertainty about progression and the need for sequential examinations over the subsequent one to two years to determine progression. It is prudent also to note that bilateral and symmetric developmental cataracts are usually expected to have a heritable component (Matthews, 2015). All acquired cataracts are potentially progressive through recurrence or progression of the causal insult. The exception is the traumatically induced cataract, which could be non-progressive if there is no persistence of inflammation. Usually eyes that have suffered BOT will have other signs to suggest that etiology (Charnock et al., 2022). Equatorial cataracts involving the periphery or equatorial lens and those presenting with vacuolar change are usually progressive. In general, the more advanced the stage of cataract, the larger impact on vision. Focal cataracts may not impart any significant effect on vision and visual behavior may be informative in these instances. Extensive or complete cataracts, in one or both eyes, however, should significantly compromise functional vision. Additionally, opacities that obstruct the central visual axis, are expected to have a significant effect on functional vision.

A dark environment is imperative for accurate examination of the posterior segment. Vitreal and fundic lesions may be missed or misinterpreted when external light scatter is present. Distant direct ophthalmoscopy, wherein the direct ophthalmoscope is held 20-50 cm from the horse’s eye, is used to identify opacities within the visual axis, especially those in the lens and vitreous.

By using this technique of retroillumination, an opacity will appear dark or in silhouette against the tapetal reflection.

Additionally, this method can be used to localize a lenticular opacity as anterior or posterior. As the observer’s axis pivots, lesions near the posterior lens nucleus will remain fixed, while those anterior to this pivot point will move in the opposite direction to the observer’s movement and those in the posterior lens will move in the same direction as the observer.

Close direct ophthalmoscopy is then performed to evaluate the fundus from a distance of 2-3 cm. For most examiners (depending upon their own refractive error), the dioptric setting of “0” will bring the peripapillary fundus and optic nerve

Continued on page 18 www.fvma.org |

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OCTOBER 6-9, 2022

SAWGRASS MARRIOTT PONTE VEDRA BEACH, FLORIDA

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Dr. Pete Morresey - BVSc, MVM, DipACT, DipACVIM

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Dr. Ruth-Anne Richter - BSc (Hon), DVM, MS

• Station 5: Stifle

Dr. Suzan Oakely - DVM, DACVSMR, DABVP (Equine), ISELP

EXCLUSIVELY SPONSORED BY:

Wet lab fees include:

• • • •

Expert instruction Rotation through all five stations Breakfast and lunch Round trip transportation between Sawgrass Marriott and Magnolia Lake Farm

Limited availability! Reserve your seat today!

EARLY BIRD RATE ENDS SEPTEMBER 6, 2022

AGENDA

Here’s an overview of

(PROGRAM

THURSDAY, OCTOBER 6 TIME

MASTERS E

8:00 a.m. - Comprehensive Equine Ultrasound Wet Lab *Off-site location. Pre-registration required.

4:00 p.m.

1:45 p.m. 2:35 p.m.

2:40 p.m. 3:30 p.m.

Early Referral - Why It’s More Important Than Ever Dr. Freeman What Practitioners Should Know About Colic Surgery and Its Complications Dr. Freeman

3:30 p.m. - 4:00 p.m. | Afternoon Break in the Masters Foyer 4:00 p.m. 4:50 p.m.

4:55 p.m.5:45 p.m.

5:45 p.m. 7:00 p.m.

FRIDAY, OCTOBER 7 TIME

7:00 a.m. 7:50 a.m.

8:00 a.m. 9:45 a.m.

What Every Veterinarian Needs to Know About the Import Process Dr. Pelzel-McCluskey Welcome Reception in the Exhibit Hall Free to all registered attendees!

For more details, scan here or visit our website at www.fvma.org/conferences

MASTERS E

Sunrise Session

Sponsored and presented by industry partners as additional CE credit hours to the FAEP program

News Hour Dr. Morresey & Dr. Ortved

9:45 a.m. - 10:30 a.m. | Morning Break in the Exhibit Hall 10:30 a.m. 11:20 a.m.

Emerging Disease Threats to the U.S. Sport Horse Dr. Pelzel-McCluskey

MASTERS A-D

11:25 a.m. 12:15 p.m.

Regenerative Medicine Dr. Ortved

Updates About Managing the Most Challenging Colic Cases Dr. Freeman

Treatment of Joint Diseases

Hyperbaric Medicine and the Sport Horse

Dr. Ortved

Dr. Slovis

12:15 p.m. - 1:45 p.m. | Complimentary Lunch in the Exhibit Hall 1:45 p.m. 2:35 p.m.

2:40 p.m. 3:30 p.m.

The Clinical Application of Advanced Imaging for Sport Horses

Biosecurity Lessons Learned From Diarrhea To Herpes

Dr. Ortved

Dr. Slovis

Neck Imaging

Clinical Pathology: Interactive Case Discussion on How To Interpret Bloodwork and Cytology

Dr. Selberg

Dr. Slovis

3:30 p.m. - 4:00 p.m. | Afternoon Break in the Exhibit Hall

4:00 p.m. 4:50 p.m.

4:55 p.m. 5:45 p.m.

5:45 p.m. 7:00 p.m.

Standing CT: What Can We See Dr. Selberg

Blocking Patterns and Imaging Dr. Selberg

Being A Better Vet: Why We Can Make Misdiagnoses and How Not To Dr. Nolen-Walston Being A Better Vet: Why We Feel Frustrated With Our Brains and How Not To Dr. Nolen-Walston

Reception & Social Hour in the Exhibit Hall

AT-A-GLANCE

what’s happening at the event!

M SUBJECT TO CHANGE)

SATURDAY, OCTOBER 8 TIME

7:00 a.m. 7:50 a.m.

8:00 a.m. 8:50 a.m.

8:55 a.m. 9:45 a.m.

MASTERS A-D

SUNDAY, OCTOBER 9 MASTERS E

TIME

Sunrise Session

7:00 a.m. 7:50 a.m.

Sponsored and presented by industry partners as additional CE credit hours to the FAEP program

Emergency Fracture Care and Immobilization Dr. Wright Management of Tarsal Fractures Dr. Wright

Global Worming: How To Talk To Owners About Strategic Parasite Control Dr. Nolen-Walston

10:30 a.m. 11:20 a.m.

11:25 a.m. 12:15 p.m.

Dr. Wright

Imaging Fractures Dr. Minshall

Sunrise Session

Sponsored and presented by industry partners as additional CE credit hours to the FAEP program

Case Study Panel Dr. Allen, Dr. Minshall and Dr. Wright

9:45 a.m. - 10:00 a.m. | Morning Break in the Masters Foyer

New Concepts in the Pathogenesis of Respiratory Disease

10:00 a.m. 10:50 a.m.

Dr. Morresey

9:45 a.m. - 10:30 a.m. | Morning Break in the Exhibit Hall Treatment of Subchondral Bone Cysts

8:00 a.m. 9:45 a.m.

MASTERS E

Weight Loss and Ill-thrift: What To Look For, What To Do

10:55 a.m. 11:45 a.m.

11:50 a.m. 12:40 p.m.

Dr. Morresey

Understanding the Pre-purchase Exam in the Equine Athlete Dr. Allen Back Pain in the Equine Athlete Dr. Allen Hind Limb Proximal Suspensory: Diagnosis and Treatment Dr. Allen

Fat Not Frisky: Reproductive Consequences of Insulin Dysregulation Dr. Morresey

12:15 p.m. - 1:35 p.m. | Complimentary Lunch in the Exhibit Hall 1:20 p.m. - Cover-all Bingo Raffle (Must be present to win!)

1:35 p.m. 3:20 p.m.

Keynote Presentation — Thirty-five Years of Equine Neurology: Cases and Learnings Dr. MacKay

3:20 p.m. - 3:40 p.m. | Afternoon Break 3:40 p.m. 4:30 p.m.

4:35 p.m. 5:25 p.m.

Imaging the Capral Sheath Dr. Minshall Imaging the Tarsal Sheath Dr. Minshall

Recruitment and Retention: Current State of the Equine Practice Dr. House Preventing Burnout and Strategies to Recharge Your Well-being

Follow us on: www.fvma.org |

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Dr. House

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@thefvma | The Practitioner 15

EARLY BIRD RATE ENDS SEPTEMBER 6, 2022 EXHIBITOR SCHEDULE OF EVENTS Thursday, October 6 Exhibitor Set Up: 12:00 p.m. - 5:00 p.m.

Welcome Reception: 5:45 p.m. - 7:00 p.m.

Friday, October 7 Exhibit Hall Hours: 9:00 a.m. - 7:00 p.m.

Morning Break: 9:45 a.m. - 10:30 a.m.

Lunch: 12:15 p.m. - 1:45 p.m.

Afternoon Break: 3:30 p.m. - 4:00 p.m.

Reception & Social Hour: 5:45 p.m. - 7:00 p.m.

Saturday, October 8 Exhibit Hall Hours: 9:00 a.m. - 1:35 p.m.

Morning Break: 9:45 a.m. - 10:30 a.m.

Lunch: 12:15 p.m. - 1:35 p.m.

Cover-all Bingo Raffle: 1:20 p.m.

Exhibitor Load-out: 1:35 pm. - 4:00 p.m.

Be an Exhibitor!

To learn more, scan the QR Code.

HOTEL INFORMATION Sawgrass Marriott Golf Resort & Spa

1000 TPC Blvd, Ponte Vedra Beach, Fla. 32082 To learn more about Sawgrass Marriott and book your room, scan the QR Code.

Exclusive FAEP Rate $220/night* and free self-parking!

Book over the phone by calling 800.228.9290

Mention Group Code: “FAEP”

*$220.00 room rate does not include $20/night resort fee

Room Block Deadline: September 6, 2022

Or until room block is sold out. After September 6, 2022, room rate will increase, if rooms are available.

Spe ROOM cial RATE

$220

THANK YOU TO OUR 2022-2023 EDUCATIONAL PARTNERS

2023 OCALA EQUINE CONFERENCE JANUARY 20-22, 2023

SAVE THE DATE! #OEC2023

WORLD EQUESTRIAN CENTER, OCALA, FLORIDA

For more information www.fvma.org/conferences OR CALL 800.992.3862

SCAN QR CODE TO SIGN UP FOR REGISTRATION DETAILS

WORLD-CLASS PROGRAM OF CUTTING-EDGE LECTURES AND HANDS-ON INSTRUCTION.

Continued from page 11 into focus. Benefits of using a direct ophthalmoscope are that it produces an upright image, the ability to alter the dioptric power of the ophthalmoscope, and the high magnification provided. Drawbacks include the short working distance (close to the animal’s head), a small field of view (a single view covers only 2-3% of the fundus), lack of depth perception, difficulty in examining the peripheral fundus, and greater distortion of the image when the visual axis is not clear. It is necessary to rotate the angle of view in multiple directions to observe as much of the fundus as possible, which is even more challenging in a non-dilated eye. The direct ophthalmoscope can also be used to evaluate structures of the eye anterior to the fundus with magnification by changing the dioptric strength of the instrument. The vitreous is usually in focus at settings of +2D to +6D, the lens at +7D to +8D and the cornea at +10 to +12D. In contrast, indirect ophthalmoscopy, which involves the use of a light source (Finoff transilluminator or an indirect headset) and a handheld lens, offers the benefit of a wider field of view, a safer working distance from the horse’s head, potential for depth perception, a greater view of the peripheral fundus, and the ability to alter the magnification by changing the diopter strength of the lens being used. Limitations of indirect ophthalmoscopy include the inverted and reversed image, the expense of binocular equipment to allow for depth perception, and the general learning curve of the technique. This technique is similar to retroillumination for lens evaluation, with the addition of a handheld lens that is held in the opposite hand.

The hand is rested on the horse's face and once the tapetal reflection is obtained, the lens is “dropped” into the beam of light to allow visualization of the fundus. Gentle movements of the lens towards and away from the eye help to bring the fundus into focus, filling the lens. Since this technique provides such a larger field of view, it is often used as a survey tool to scan the entire fundus and if a lesion is identified, the examiner can go back with the direct ophthalmoscope and evaluate it further with greater magnification.

The vitreous is normally not visualized unless an anomaly or abnormality is present. Retroillumination developmental inclusions are a common finding and are usually an incidental, non-progressive finding. However, they must be differentiated from acquired vitreal opacities which are usually a consequence of inflammation. These pathologic vitreal inclusions may include fibrin, cellular debris, hemorrhage, post-inflammatory membranes, or strands of degenerate vitreous. These lesions are likely to have a permanent and persistent impact on functional vision.

18 The Practitioner

The equine fundus may exhibit a wide range of normal variations. Familiarity with these variants is critical to the accurate distinction between variant and abnormality. There are some distinct features of fundic pathology that an examiner can be confident in calling, however. Retinal detachment and optic nerve atrophy (with concurrent loss of visual function) are obvious examples, but others include loss or attenuation of retinal or choroidal blood vessels, and areas of pigment loss or dispersion, areas of white scleral reflex, or pigmentation within the tapetal fundus. A retinal detachment can appear as a focal area of hyporeflectivity, or as a diffuse inability to focus on the fundus when complete.

The tapetal fundus should have a consistent reflectivity over its entirety. Areas that appear hyperreflective to their surroundings suggest retinal thinning. These areas may be scar tissues and may not signal active disease, though depending on the degree of fundus involvement could suggest a significant impact on vision. Lesions that are geographically extensive or involve vascular attenuation are likely to significantly impair vision.

Hyporeflective areas within the tapetum are suggestive of an active disease process (inflammation, hemorrhage, etc.). Active chorioretinal inflammation is rare to see in the horse, usually the examiner observes the consequences rather than the process.

Most fundic lesions are observed in the peripapillary fundus or in the non-tapetal fundus of the horse. Generally, these appear as foci of depigmentation, often with hyperpigmented centers and pigment mottling. As with tapetal lesions, the extent of involvement will determine the likely impact on function. The challenge arises with focal chorioretinopathy. “Bullet hole” retinopathy is exceedingly common and may be seen in as many as 80% of adult horses and likely is the manifestation of some generic inflammatory insult (Matthews, 2016). A single or few lesions are not expected to impact vision, although larger areas of involvement, especially if they are densely or widely distributed across the entire pigmented fundus or where they form a linear coalescing distribution in the ventral peripapillary fundus, have been associated with behavioral changes suggestive of visual impairment, although electroretinographic evaluation did not support depressed photoreceptor function in a small cohort of similarly affected individuals (Albaugh et al., 2014; Matthews, 2016). Chorioretinal lesions, even so-called “butterfly lesions,” are not alone an indicator of equine recurrent uveitis. They may, however, support that diagnosis if there are other concurrent signs of intraocular inflammation. Pigmentary retinopathy, in which there is generalized dispersal of fundic pigment with irregular hyperpigmentation in the tapetal fundus, is seen with equine motor neuron disease. Affected animals likely have significant visual function impairment. These lesions are not to

Issue 1 • 2022

be confused with the more focal linear distribution of pigment near the tapetal-non-tapetal junction seen in aged animals with senile retinopathy, the impact of which on vision is unknown but likely minimal.

Proliferative lesions of the optic nerve are commonly observed in aged horses and are not generally believed to cause significant visual impairment. Optic nerve atrophy will appear as a pale and non-vascularized optic disc, with visual impairment and mydriasis.

Caveats and Considerations In some instances, the veterinarian will be asked to perform a PPE on a horse that has been unilaterally enucleated. Horses presenting with only one functional eye, the contralateral eye having been enucleated or being phthisical, may be suitable for purchase with reservation. Buyers should be made aware, however, that loss of an eye will significantly impair that animal’s binocular vision and depth perception which may affect jumping ability, and, in instances where an eye is phthisical, it may be a source of chronic pain. That said, a preponderance of animals is able to return to work in a variety of disciplines following unilateral enucleation (Utter et al., 2010; Wright et al., 2018).

Another important consideration to bear in mind when performing ophthalmic PPEs is the potential heritability of ocular and periocular lesions. Although in general, there is little

known about the heritability of most ophthalmic conditions in horses, advancing technologies and diagnostic tools are providing with insight into some. For instance, a missense mutation in damage-specific DNA binding protein 2 (DDB2) has been recently identified as a genetic risk factor for limbal and third eyelid SCC in Haflingers, Belgians Draft Horses, and Rocky Mountain horses (Bellone et al., 2008; Crausaz et al., 2020). Given that certain breeds and coat colors/patterns experience an increased incidence of certain conditions, a genetic predisposition is likely at play. Individuals with a missense mutation of the premelanosome protein gene (PMEL) exhibit hypopigmented phenotypes, usually the highly coveted silver coat color, as well as multiple congenital ocular anomalies (MCOA). A variety of breeds including the Icelandic, Rocky Mountain Horse, Kentucky Mountain Saddle Horse, Belgian Draft, Morgan, American Miniature Horse, Shetland Pony, and Exmoor Pony have been reported to exhibit ocular changes related to the developmental influence of the PMEL mutation (Andersson, et al., 2013). Horses exhibiting leopard spotting complex patterns are at increased risk for the development of congenital stationary night blindness (CSNB) and equine recurrent uveitis (Bellone et al., 2008; Rockwell et al., 2020; Sandmeyer, 2020). In fact, there is complete concordance between homozygosity for LP (LP/LP) genotype and CSNB (Bellone et al., 2013). The association is not quite so clear cut for ERU, but horses with at least one copy of the LP allele, and those that additionally have other depigmentation factors have a greater risk for the development of ERU (Rockwell et al., 2020). Genetic testing is available for a number of equine ocular conditions at the University of California-Davis Veterinary Genetic Laboratory. As more genetic testing becomes available, genetic counseling and routine genetic testing may become a fixture of the PPE.

Writing the Report

Figure 4: Extensive chorioretinal scarring ventral to the optic disc in a horse with active and chronic uveitis.

Image courtesy of Dr. Caryn E. Plummer.

As with any portion of a medical record, the pre-purchase report should be as detailed as possible. Text should be written in a way to serve as a baseline for future examinations. Notations of abnormalities or variants should include location, shape, color, size, optical properties (transparent or opaque), and impact on other structures (i.e. a previous eyelid wound resulting in corneal exposure). If possible, photographic documentation can also be utilized to record findings. Results of any ophthalmic testing performed (neuro-ophthalmic reflexes and responses, tonometry, ocular surface staining, etc.) should also be included.

Lesion identification is only the first step in the process. Each anomaly or abnormality should be considered for its effect on (1) the affected ocular structure and its function/performance, (2) the globe, (3) vision and (4) comfort. Lesions should be deemed active or inactive and a qualified assessment of whether the lesion is static or expected to progress should be attempted.

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thefaep |

@thefvma | The Practitioner 19

Additionally, a statement should be made as to the need or potential need for therapy.

It is important to remember that it is not the veterinarian’s position to express opinions on the suitability of the animal for the purposes intended. Rather, the report serves as a tool to help the buyer make an educated decision about the potential investment. In instances where equivocal lesions, those whose impact on vision or likelihood of progression is unknown, are noted, a frank conversation with the buyer is necessary. Referral to a board-certified veterinary ophthalmologist who may be able to provide additional insight into the impact or prognosis of a lesion or advanced testing may be advisable. Including in the written report the recommendation for referral may prevent some future headaches.

Take Homes • Choose your surroundings carefully: Do it in the dark!

• Pharmacologic mydriasis is recommended to thoroughly evaluate the posterior segment and pupil mobility • Be patient and systematic, thorough and meticulous with your examination • The goal of the ophthalmic PPE: accurately describe an anomaly or abnormality and give an opinion on its effect on functional vision or comfort as well as its likely progression • Practice, practice, practice! The more eyes you look at, the better your assessments will become.

• Document, document, document! Be as detailed as possible with your report.

References A llbaugh R A, Ben-Shlomo G, Whitley R D. Electroretinogram evaluation of equine eyes with extensive 'bullet-hole' fundic lesions. Vet Ophthalmol. 2014 ;17 (1):129-33.

Andersson LS, Wilbe M, Viluma A, Cothran G, Ekesten B, Ewart S, Lindgren G. Equine multiple congenital ocular anomalies and silver coat colour result from the pleiotropic effects of mutant PMEL. PLoS One 2013;8(9):e75639.

Bellone RR, Brooks SA, Sandmeyer L, Murphy BA, Forsyth G, Archer S, Bailey E, Grahn B. Differential gene expression of TRPM1, the potential cause of congenital stationary night blindness and coat spotting patterns (LP) in the Appaloosa horse (Equus caballus).

Genetics. 2008;179(4):1861-70.

Bellone RR, Liu J, Petersen JL, Mack M, Singer-Berk M, Drogemuller C, et al. A missense mutation in damagespecific DNA binding protein 2 is a genetic risk factor for limbal squamous cell carcinoma in horses. Int J Cancer. 2017; 141: 342–53.

20 The Practitioner

Bergstrom BE, Labelle AL, Pryde ME, Hamor RE, Myrna KE. Prevalence of ophthalmic disease in blueeyed horses. Equine vet. Educ. 2014; 26 (8): 438-440.

Charnock LN, Keys DA, McMullen RJ. Clinical findings associated with blunt ocular trauma in horses: a retrospective analysis. Veterinary Ophthalmology 2022;25:52–61.

Crausaz M, Launois T, Smith-Fleming K, McCoy AM, Knickelbein KE, Bellone RR. DDB2 Genetic Risk Factor for Ocular Squamous Cell Carcinoma Identified in Three Additional Horse Breeds. Genes (Basel).

2020;11(12):1460.

Dwyer AE. Ophthalmology in Equine Ambulatory Practice. The Veterinary clinics of North America Equine practice. 2012; 28: 155-174.

Dwyer AE. Practical field ophthalmology. In: Equine Ophthalmology, 3rd ed. Ed. B.C. Gilger. Ames, IA: John Wiley & Sons, Inc. 2017; 72-111.

Gelatt KN, Gum GG, Mackay EO. Evaluation of mydriatics in horses. Veterinary and Comparative Ophthalmology. 1995; 5: 104-107.

Gerding JC, Gilger BC. Prognosis and impact of equine recurrent uveitis. Equine Vet J. 2016;48(3):290-8.

Malalana F, McGowan TW, Ireland JL, Pinchbeck GL, McGowan CM. Prevalence of owner-reported ocular problems and veterinary ocular findings in a population of horses aged ≥ 15 years. Equine Veterinary Journal 2019; 51: 212–217.

Matthews AG. Eye examination as part of the equine prepurchase examination. Equine Veterinary Education 2016; 28 (10): 566-591.

Rockwell H, Mack M, Famula T, Sandmeyer L, Bauer B, Dwyer A, Lassaline M, Beeson S, Archer S, McCue M, Bellone RR. Genetic investigation of equine recurrent uveitis in Appaloosa horses. Anim Genet. 2020; 51(1):111-116.

Rubin LF. Auriculopalpebral nerve block as an adjunct to the diagnosis and treatment of ocular inflammation in the horse. J Am Vet Med Assoc. 1964; 144: 1387-1388.

Sandmeyer LS, Kingsley NB, Walder C, Archer S, Leis ML, Bellone RR, Bauer BS. Risk factors for equine recurrent uveitis in a population of Appaloosa horses in western Canada. Vet Ophthalmol. 2020; 23(3):515-525.

Utter ME, Wotman KL, Covert KR. Return to work following unilateral enucleation in 34 horses (2000–2008).

Equine vet. J. 2010; 42 (2): 156-160.

Wright K, Ireland JL, Rendle DI. A multicentre study of longterm follow-up and owner satisfaction following enucleation in horses. Equine Vet J. 2018; 50(2):186–91. https://aaep.org /sites/default/files/Documents/ Guidelines%20for%20Reporting%20Purchase%20 Examinations.pdf

Issue 1 • 2022

Eric T. Alexopoulos, DVM Dr. Eric Alexopoulos is a 2020 graduate of the University of Florida (UF) College of Veterinary Medicine.

Following a rotating internship at Tufts University School of Veterinary Medicine, Dr. Alexopoulos returned to UF where he is currently pursuing specialty training as a resident in comparative ophthalmology.

Horses make us better.

Together, we make them better, too.

Caryn E. Plummer, DVM, DACVO Dr. Caryn Plummer, a native Floridian, graduated with a biology degree from Yale University in 1997. She is an honors graduate of the University of Florida College of Veterinary Medicine class of 2002. Following veterinary school, she completed an internship in small animal medicine and surgery at Michigan State University College of Veterinary Medicine followed by a residency in comparative ophthalmology at the University of Florida. She is a Diplomate of the American College of Veterinary Ophthalmologists (2006).

After completing specialty training, Dr. Plummer joined the faculty at the UF College of Veterinary Medicine as an assistant professor in 2006. She is currently a tenured professor at the UF. Her research interests include corneal wound healing, immune-mediated uveitis, and glaucoma. She has lectured extensively both in the USA and abroad on many topics associated with clinical veterinary ophthalmology and animal models of ophthalmic disease, especially glaucoma. She is is a contributing author to the Gelatt's classic textbook Veterinary Ophthalmology (4rd, 5th and 6th editions) and an associate editor for the recent 6th edition. She is also a charter member of, and currently serves as the secretary/treasurer for, the International Equine Ophthalmology Consortium.

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Reduce inflammation Restore synovial joint lubrication Repair joint cartilage Reverse the disease cycle When you start with it early and stay with it as needed, horses may enjoy greater mobility over a 2, 4, 5 lifetime. Discover if Adequan is the right choice. Visit adequan.com/Ordering-Information to find a distributor and place an order today.

BRIEF SUMMARY: Prior to use please consult the product insert, a summary of which follows: CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian. INDICATIONS: Adequan® i.m. is recommended for the intramuscular treatment of non-infectious degenerative and/or traumatic joint dysfunction and associated lameness of the carpal and hock joints in horses. CONTRAINDICATIONS: There are no known contraindications to the use of intramuscular Polysulfated Glycosaminoglycan. WARNINGS: Do not use in horses intended for human consumption. Not for use in humans. Keep this and all medications out of the reach of children. PRECAUTIONS: The safe use of Adequan® i.m. in horses used for breeding purposes, during pregnancy, or in lactating mares has not been evaluated. For customer care, or to obtain product information, visit www.adequan.com. To report an adverse event please contact American Regent, Inc. at 1-888-354-4857 or email pv@americanregent.com.

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www.adequan.com 1 Data on file.

2 Adequan® i.m. Package Insert, Rev 1/19.

3 Burba DJ, Collier MA, DeBault LE, Hanson-Painton O, Thompson HC, Holder CL: In vivo kinetic study on uptake and distribution of intramuscular tritium-labeled polysulfated glycosaminoglycan in equine body fluid compartments and articular cartilage in an osteochondral defect model. J Equine Vet Sci 1993; 13: 696-703.

4 Kim DY, Taylor HW, Moore RM, Paulsen DB, Cho DY. Articular chondrocyte apoptosis in equine osteoarthritis. The Veterinary Journal 2003; 166: 52-57.

5 McIlwraith CW, Frisbie DD, Kawcak CE, van Weeren PR. Joint Disease in the Horse.St. Louis, MO: Elsevier, 2016; 33-48.

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