Page 94 - WSAVA2018
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 25-28 September, 2018 | Singapore
*** For the rest of the exam MAGNIFICATION is extremely important to identify changes or pathology. Without magnification impacted meibomian glands, ectopic cilia, distichia, corneal vessels and other subtle changes will be missed. A simple otoscope head with a magnifying lens and bright light source works great. Other magnifying glasses or headloupes are also available.
E. Eyelids
The eyelids are examined for abnormalities of position, function and structure such as lagophthalmos, ptosis, trichiasis, ectropion, entropion, blepharitis, lid neoplasms, etc.
The blink reflex should be evaluated. The efferent limb of this reflex requires the integrity of the facial nerve (CN VII) and the orbicularis oculi muscle. The afferent limb may be a menace (CN II), corneal sensation (CN V) or touch sensation to the periorbital skin (CN V). Rapidity and completeness of the blink should be evaluated.
The lower and upper eyelids should touch the globe. Lower lid-globe contact is important to prevent accumulation of tears and debris. The lower “lacrimal lake” may be grossly distorted by anesthetics and tranquilizers. Cilia or eyelashes occur mainly on the dog’s upper lid in three irregular rows. The lower eyelids of dogs and both eyelids of cats are usually void of cilia. The eyelid contours are regular and gently curved, partially exposing the openings of the tarsal
or Meibomian glands (gray line). The duct orifices are frequently raised and nonpigmented. Aberrant cilia (distichia) may emerge from the spaces among the Meibomian gland ducts, or the actual duct orifices. Ectopic cilia emerge from the within the palpebral conjunctiva of the upper lid and are frequently the same color as the dog’s hair coat. They can escape detection without careful examination.
F. The Conjunctiva and the Nictitating Membrane
The palpebral conjunctiva is examined by manual eversion of the upper and lower eyelids. Excessive lymphoid follicles, increased vascularity, foreign bodies, ectopic cilia, obstructed tarsal glands, hemorrhage, lacerations, abnormal growths and edema (chemosis) may be abnormalities observed. Coloration of the conjunctiva can be used to assess the presence of anemia and icterus. Because the palpebral conjunctiva is transparent, chalazia or impacted Meibomian glands appear as slightly raised yellow masses.
Examination of the palpebral (outer) and bulbar (inner) surfaces of the nictitans is important for diagnosis of several common external ocular conditions. Frequent abnormalities are eversion of the cartilage of the nictitans, prolapse of the gland (cherry eye), foreign bodies, follicular conjunctivitis, enlargement of the secretory gland, foreign bodies, follicular conjunctivitis,
and enlargement of the bulbar lymphoid tissue. G. The Sclera
The sclera should be scrutinized for change in color, abnormal masses, and tears or lacerations. Small vessels in the episclera are usually visible and occasionally a large vortex vein (especially the dorsolateral vein) can
be seen. Enlargement and congestion of the episcleral veins occur commonly with glaucoma. This venous enlargement remains even after the glaucoma is “controlled”. Hyperemia of the episcleral vessels occurs in association with inflammatory conditions. The “ciliary flush” or limbal hyperemia from iridocyclitis is usually less affected by topical phenylephrine while that associated with the conjunctivitis will usually blanch. The perilimbal scleral vessels are small straight and immovable vs larger mobile and branching conjunctival vessels.
H. The Cornea
Corneal sensitivity (corneal reflex) is tested by a small wisp of cotton gently touched to the cornea. (This must be done prior to topical anesthetic instillation). If the animal sees the stimulation, you will get a false positive.
The cornea is normally transparent, avascular, moist,
and unpigmented with a smooth, even contour. It should be carefully examined for loss of transparency (edema
or infiltrates), opacity, vascularization, pigmentation, dryness, growths, foreign bodies, lacerations, changes of contour, and ulceration.
Two types of vascularization occur in the cornea: superficial and deep. Superficial vessels occur in the anterior one-half of the corneal stroma, are usually continuous with visible conjunctival vessels, are “tree- like”, and associated with external corneal diseases. Deep vessels appear as small, fine vessels in the corneal stroma that extend from the anterior sclera or deeper limbal vessels (paint brush border), and are associated with intraocular inflammation.
Examination of the cornea is incomplete without utilization of topical ophthalmic stains. Fluorescein is used to demonstrate the presence or absence of corneal ulcers. For topical use, fluorescein impregnated paper strips are preferred to fluorescein solution to insure sterility.
Because the water-soluble fluorescein stains the preocular film, a faint green may occur on the corneal surface.
The corneal epithelium is lipid-selective and prevents any appreciable corneal penetration by fluorescein.
In the presence of a corneal epithelial defect, the dye rapidly diffuses into the corneal stroma. An area of fluorescein retention by corneal stroma is indicative of an epithelial defect (a corneal ulcer/erosion).
Rose bengal is a valuable stain in the evaluation of

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