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Lens Luxation 581

PEARLS & CONSIDERATIONS Prevention Client Education
• There is no vaccine available in the United • Leishmaniasis is a zoonotic disease that can
Comments
VetBooks.ir • L. infantum is transmitted in blood transfu- Brazil. Vaccinated dogs may be seropositive • Leishmaniasis is often a chronic infection in Diseases and Disorders
be fatal in humans.
States. Vaccines are marketed in Europe and
sions, and it is recommended to screen blood
dogs that may not manifest for years after
to L. infantum.
donors for infection in endemic regions or
if the dogs originated from or have traveled • Specific insecticidal collars and topical insect the initial exposure.
repellent prevent vector transmission.
to such an area. Foxhound donors in North • If possible, keep pet dogs inside during dawn SUGGESTED READING
America should be screened for infection by and dusk, the feeding times of sandflies. Solano-Gallego L, et al: LeishVet guidelines for the
PCR. practical management of canine leishmaniosis.
• Evidence supports venereal and intrauterine Technician Tips Parasit Vectors 4:86, 2011.
transmission of leishmaniasis from dam to Response of dogs to treatment is slow, and it AUTHOR: Gad Baneth, DVM, PhD, DECVCP
pup. often takes a month or more before clinical EDITOR: Joseph Taboada, DVM, DACVIM
improvement.

Lens Luxation Bonus Material Client Education
Sheet
Online

BASIC INFORMATION • The cornea may be focally or diffusely cloudy ○ Chronic anterior uveitis (p. 1023)
from edema secondary to corneal endothelial ○ Glaucoma with associated buphthalmos
Definition damage or increased intraocular pressure (p. 387)
Complete dislocation of the lens anteriorly (IOP). ○ Intraocular neoplasia (p. 559)
(into the anterior chamber) or posteriorly • Vision change noted by the owner, depend- ○ Hypermature cataract (p. 147)
(into the posterior segment/vitreous) from its ing on the visual status of the contralateral ○ Severe ocular trauma (results in other
normal position occurs as a result of abnormal eye significant ocular damage)
development or degeneration (primary: usually a ○ Age-related (older dogs/cats)
bilateral, inherited condition in dogs) or rupture PHYSICAL EXAM FINDINGS
or degeneration (secondary: acquired) of the • Systemic: generally unremarkable DIAGNOSIS
lens zonules (fibers from the ciliary body that • Ophthalmic
hold the lens in place). ○ Anterior chamber depth abnormal: shallow Diagnostic Overview
with anterior luxation; deep with posterior Suspected on physical exam after owner
Synonyms luxation presentation for reduced vision or observed
Lens subluxation: partial dislocation of the lens ○ Iridodonesis (trembling of the iris) ocular abnormality. A complete ophthalmic
○ Phacodonesis (trembling of the lens) exam is indicated to confirm and characterize
Epidemiology ○ Aphakic crescent (visible edge of lens in the luxation and identify predisposing causes
SPECIES, AGE, SEX the pupil creates a crescent-shaped area that can be treated.
• Primary: occurs most commonly in middle- in the pupil where there is no lens)
aged dogs, especially terrier breeds ○ Vitreous presentation in the anterior Differential Diagnosis
• Secondary: dogs and cats; any age chamber (appears as fine white cotton • Glaucoma
strands) • Anterior uveitis
GENETICS, BREED PREDISPOSITION ○ Retina visualized without an ophthalmo-
• Primary: terrier breeds predisposed; typically scope (i.e., with penlight or transillumina- Initial Database
3-8 years old; due to a genetic mutation that is tor) Ophthalmic exam (p. 1137):
widespread in several dog breeds. DNA testing ○ Focal or diffuse corneal edema from • Menace response, dazzle and pupillary light
available (www.offa.org/dnatesting/pll.html). mechanical damage to corneal endothe- reflexes
• German shepherd, American Eskimo, Shar- lium with anterior luxation • Intraocular pressure (IOP); normal = 10-
pei, Lancaster heeler, border collie, and some ○ Glaucoma can result in secondary lens 18 mm Hg with Tono-Pen or TonoVet
spaniels may be predisposed. subluxation by buphthalmos; conversely, • Penlight or slit-beam exam to determine if
primary lens luxation can also result in lens luxation is primary or secondary, evaluate
ASSOCIATED DISORDERS secondary glaucoma. depth of anterior chamber, and assess cornea,
• Anterior uveitis ○ Cataract with chronic lens luxation; a lens, and vitreous for opacities
• Cataract hypermature cataract may result in lens • Direct or indirect ophthalmoscopy to
• Corneal endothelial-associated edema luxation or subluxation. evaluate the posterior segment for retinal
(anterior luxation) ○ Blindness from cataract, glaucoma, retinal detachment and optic nerve and retinal
• Glaucoma detachment degeneration
• Vitreous degeneration • Complete ophthalmic exam of the contra-
• Intraocular neoplasia Etiology and Pathophysiology lateral eye is indicated, especially in cases
• Retinal detachment • Primary lens luxation occurs because of an of primary lens luxation and in predisposed
autosomal recessive inherited, progressive breeds.
Clinical Presentation defect in the lens zonules and is usually
HISTORY, CHIEF COMPLAINT bilateral. Advanced or Confirmatory Testing
• Signs of ocular pain in cases of anterior • Secondary lens luxation occurs as a result of Ocular ultrasound if opacities of the lens
lens luxation, including tearing, redness, degeneration and/or stretching of the lens or transmitting media prevent complete
and squinting/blepharospasm zonules; causes include examination

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