Basic Procedures: Ocular and Auricle

Ocular

Eye

Orbit

The hole in which the eye sits surrounded and formed by the maxilla, zygomatic, frontal, and ethmoid bones

Palpebrae

Eyelids

Cilia

Eyelashes or small hairs

Conjunctiva

The membrane that lines the insides of the eyelids and eye itself. It secretes mucus which helps to lubricate the eye

Lacrimal Gland

Makes tears which are secreted through the lacrimal duct. It is also connected to the nasal passage via the nasolacrimal duct

Nictitating Membrane

The third eyelid. It is located near the medial canthus and sometimes protrudes if the eye is painful, from trauma, or if the animal is sedated.

Sclera

The white part of the eye

Cornea

Clear and retracts in light. It has no vessels. It is made up of 10 layers and forms the anterior portion of the eye. It is crucial for protecting the eye and focusing light. Prompt attention to disorders or injuries is essential due to its critical role in vision.

Uvea

The vascular tunic made of the choroid, ciliary body, and iris

Iris

The colored part of the eye

Ciliary Body

Helps to focus the eye

Choroid

Helps guard against glare

Pupil

Is in the central part of the iris. Light passes through it

Optic Disc

Head of the optic nerve

Anterior Chamber

Located between the front of the lens and cornea

Aqueous Humor

Fluid

Posterior Chamber

Located between the iris, lens, and ciliary body

Vitreous Chamber

located between the retina and iris

Keratitis

Inflammation of the outer cornea. Common signs include blood vessel development, cloudiness due to fluid buildup, cellular infiltrates, pigmentation, or fibrous tissue formation.

Ulcers

Sores

Pannus

Uberreiter disease. A rapidly spreading, longterm inflammation and swelling of the surface of the cornea in both eyes, starting at the corneal edge and spreading. It is common in specific breeds like German Shepherds and requires lifelong treatment with topical corticosteroids and/or cyclosporine. Concurrent conditions like bacterial infections or dry eye must also be managed.

Ulcerative Keratitis

Corneal ulcers. Diagnosed using specialized dye drops. Treatment for shallow ulcers typically involves topical antibiotics and addressing underlying causes. Atropine may be used to dilate the pupil and reduce pain but can reduce tear production.

Ocular Fundus

Retina, choroid, and optic disk. Inherited abnormalities play a significant role in retinal diseases.

Collie Eye Anomaly

An inherited defect present at birth in Collies and related breeds, involving incomplete development of the choroid or retina and choroid. Severe cases may involve optic nerve abnormalities and retinal detachment. Vision is typically unaffected unless detachment occurs. A genetic test is available

Retinal Dysplasia

Abnormal development of the dysplasia. Present at birth due to trauma, genetic defect, or in utero damage. Inherited in various breeds and can range from asymptomatic to causing visual impairment or blindness with retinal detachment. 

Lens

Located behind the iris. Focuses light onto the retina. Common disorders affect its transparency (cataracts) or position

Cataracts

Cloudy eye lens

Lens Displacement

More common in Terrier breeds as an inherited defect but can also result from trauma, glaucoma, or long-standing cataracts.

Complete Anterior Displacement

Causes sudden, severe signs and frequently is accompanied by glaucoma and swelling of the cornea. Surgical removal is the only effective treatment.

Posterior Displacement

May show no signs or be associated with inflammation or glaucoma. Partially dislocated lenses cause iris and lens trembling. Treatment depends on the severity of signs

Retinal Detachments

Separation of the retina from the back of the eye, impairing function due to blood supply disruption. Associated with congenital retinal disorders, chorioretinitis, trauma, eye surgery, and tumors

Glaucoma

Caused by an imbalance in aqueous humor production and drainage, leading to increased intraocular pressure that can damage the retina and optic disk. Early signs include sluggish pupils, conjunctival vein congestion, mild eye enlargement

Open-Angle Glaucoma

Painless and gradual vision loss

Closed-Angle Glaucoma

Sudden, painful increase in IOP with redness and vision loss

IOP

Intraocular pressure

Schirmer Tear Test (STT)

Measures basal and stimulated tear production. Normal is generally > 15 mm/min, but >20 mm is typical. 10-15 mm suggests keratoconjunctivitis Sicca. Should be performed before applying topical medications

KCS

Keratoconjunctivitis Sicca

Fluorescein Stain

Detects corneal ulcers. Cobalt blue light enhances viualization

Tonometry

Measures intraocular pressure. Crucial for every patient with a red eye, those with glaucoma risk, and to monitor uveitis

Enucleation

Surgical eye removal

Eyelid Laceration Repair

Prompt repair is crucial. Even thin flaps of tissue should be preserved. Debridement, precise marginal skin suture placement for alignment, and subcutaneous knot placement are important

Temporary Tarsorrhaphy

A veterinary surgical procedure where the upper and lower eyelids are temporarily sewn together to protect the cornea, particularly after conditions like proptosis or corneal ulcers

Chronic Uveitis

An inflammatory disease of vascular tissue deep in the eye

Cataract Surgery

Lens replacement surgery

Direct Ophthalmoscopy

This method examines all aspects of the eye, particularly the retina and optic nerve head. The examiner holds the instrument close to their own eye and the animal’s eye, and adjusts the focus to view different layers of the eye

Indirect Ophthalmoscopy

This technique uses a condensing lens to create a magnified, inverted image of the fundus. It provides a larger, panoramic view, making it easier to visualize the entire retina.

Fundus

The back of the eye

Diopter Disc

Changes the lenses for different focus capabilities

Readout Window

Displays which lens is currently selected by the diopter disc

Aperture

Selects the opening in which the light passes through. Also has different colored filters

Miosis

A small or constricted pupil

Mydriasis

A dilated pupil

Anisocoria

Different sized pupils. May suggest trauma or neurologic disease

Pupillary Light Reflex (PLR)

Pupils should constrict in light and dilate in dark

Proptosis

An eye that has popped out of the socket

Hyphemia

Blood in the anterior chamber of the eye

Hypopyon

Pus in the anterior chamber of the eye

Entropion

Rolling in of the eyelid

Cherry Eye

Prolapsed gland of the third eyelid. The gland should never be removed surgically or dry-eye will occur. The gland is typically replaced or tacked down surgically back under the third eyelid

Canthus

Refers to the corner of the eye. Medial canthus is the corner toward the nose; the lateral canthus is the corner toward the ear

Middle Ear

Tympanic cavity and the tympanic bulla. The auditory tube connects the bulla to the sinuses, regulating pressure

Tympanic Cavity

Air-filled. Contains ossicles, auditory tube, cranial nerve branches

Tympanic Bulla

Ventral, bony expansion

Inner Ear

Within the temporal bone, includes the vestibule, cochlea, and semicircular canals

Semicircular Canals

Involved in hearing and balance, innervated by vestibular and cochlear nerves

Otitis Interna

Inflammation of the inner ear

Fungus

Yeast

Tympanic Membrane

Eardrum

Otitis Externa

External ear infection

Stenotic

Narrowed

Hyperplasia

Closing of the ear canal as a result of a chronic ear infection

Drainage

In less severe cases, a veterinarian may do this to the hematoma with a needle and a syringe

Steroid Injections

This may help reduce inflammation and prevent the hematoma from refilling

Surgery

For larger or persistent hematomas, this may be recommended. This typically involves making an incision, draining the blood, suturing the skin to prevent reaccumulation, and potentially applying a bandage

Speculum

Cone

Otodectes Cynotis

Ear mites

Cytology

Should always be performed before treatment to guide therapy. Samples should be collected from as close to the junction of the vertical and horizontal canals as possible by gently spinning a swab. Avoid aggressive scooping, which can cause trauma and ulcers

Cocci

Spherical bacteria

Bacilli

Rod-shaped bacteria

WBC

White blood cells

Sample Collection

The ear pinna is gently pulled up to expose the ear canal. A clean cotton-tipped applicator is inserted into the ear canal, reaching the junction of the horizontal and vertical canals. The swab is gently rotated to collect debris and exudate

Slide Preparation

The microscope slide is labeled with the patient’s name and which ear the sample is from. The swab is gently rolled onto the slide, spreading the collected material thinly

Heat Fixation and Staining

Some samples may be flamed briefly to help preserve the cells and prevent staining. The slide is stained using a modified Wright's stain, such as Diff-Quik. 

Microscopic Examination

The stained slide is examined under a microscope to identify microorganisms, inflammatory cells, or other abnormalities