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582 Lens Luxation

TREATMENT

VetBooks.ir Treatment Overview
Therapeutic goals are to remove an anterior
lens luxation or lens subluxation early to
avoid secondary complications and to remove
posterior lens luxation or prevent lens from
entering anterior chamber by constriction of
the pupil. Management of associated increased
IOP and uveitis may also be indicated.
Acute and Chronic Treatment
Primary:
• Acute anterior lens luxation is considered
an emergency.
• Determine IOP; treat if pressure elevated
(p. 387).
• Prompt referral of acute anterior lens luxation
to a veterinary ophthalmologist for surgical
lens removal (lensectomy) LENS LUXATION Canine eye with a posterior lens luxation (only the dorsal-most one-third of the lens is
○ Intracapsular lens extraction (ICLE) (entire visible in the ventral margin of the pupil). The optic nerve and retinal vessels are visible without the aid of an
lens removed) or phacoemulsification ± ophthalmoscope.
intraocular lens sutured in place to restore
emmetropia (normal vision, neither
farsighted nor nearsighted; without an
intraocular lens implant, animals are for increased IOP or progression of lens • Genetic testing of terriers to be used for
14 diopters hyperopic [farsighted] with instability. breeding
abnormal vision) • Contralateral eye should be monitored for
○ If lens only subluxated: phacoemulsifica- lens position in predisposed breeds; lens Technician Tips
tion (ultrasonic fragmentation of the lens) instability should prompt early referral for Ensure owners are aware of the early symptoms
with capsular tension ring and foldable phacoemulsification. of glaucoma, uveitis, and the risk for involve-
acrylic intraocular lens (IOL) ment of the contralateral eye in terriers and
○ To reduce risk of glaucoma, concurrent PROGNOSIS & OUTCOME the need for continued, long-term monitoring
laser endocyclophotocoagulation (ECP) of both eyes.
should be considered at the time of lens • Varies, depending on underlying cause,
removal. duration, and extent of the lens displacement Client Education
• If referral is not possible and the lens is and anterior versus posterior luxations • Breed predisposition for bilateral involvement
luxated anteriorly, consider pupil dilation • Most common complications are glaucoma in terriers
and intravenous mannitol to shrink the and retinal detachment (≤50% of cases). • With or without surgical intervention,
vitreous and shift the lens into the vitreous, • Early surgical intervention by phacoemulsifi- affected eyes are at increased risk for retinal
then lifelong topical miotic treatment (e.g., cation while the lens is subluxated increases detachment and glaucoma.
prostaglandin analog [p. 387]) to trap the success. • Genetic testing is available to distinguish
lens in the vitreous. • Lower risk of retinal detachment with affected, carrier, and normal dogs. Homozy-
• Similarly, if lens luxation is posterior, topical phacoemulsification compared with ICLE gous affected dogs can luxate lenses between
miotic treatment can restrict lens movement. • Capsular tension ring and foldable acrylic 4 and 8 years of age.
Consider referral for surgery because medical IOL may restore normal vision, with reduced • Animals that undergo surgical removal of
therapy alone does not prevent glaucoma or complications and risk of luxation. the lens and do not receive an IOL implant
luxation-associated vision loss. • Lens phacoemulsification combined with have vision that, in human equivalence, is
• Secondary: treat underlying cause. ECP to manage secondary glaucoma results worse than 20/400 and corresponds to being
in the most favorable long-term prognosis. legally blind.
Behavior/Exercise
Dogs with lens instability or lens luxation PEARLS & CONSIDERATIONS SUGGESTED READING
should avoid head shaking, and toys that elicit Davidson MG, et al: Diseases of the lens and cata-
such behavior should be removed. Comments ract formation. In Gelatt KN, editor: Veterinary
• Terriers affected with lens luxation, regardless ophthalmology, ed 4, Ames, IA, 2007, Blackwell,
Possible Complications of severity, should not be used for breeding. pp 859-887.
• Lens luxation is associated with an increased • Dog breeders should be counseled and AUTHOR: David A. Wilkie, DVM, MS, DACVO
risk for retinal detachment and glaucoma. genetic testing considered for at-risk breeds EDITOR: Diane V. H. Hendrix, DVM, DACVO
• Lenses that are luxated will become catarac- (http://www.offa.org/dnatesting/pll.html).
tous (p. 147).
Prevention
Recommended Monitoring • Dilated ophthalmic exam of all individuals of
• Monitor for cataract development (p. 147). predisposed breeds to detect early phacodo-
• Eyes with lens instability or lens luxa- nesis, aphakic crescent, and anterior vitreous
tion should be monitored q 2-4 months presentation (vitreous rostral to the lens)

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