Secondary lens luxation may be observed secondary to severe trauma or intraocular disease and is not considered a primary condition.
Primary lens luxation has been reported in the Miniature Bull terrier, Lancashire Heeler, Shar Pei, Chinese Crested, Volpino Italiano, Border Collie, Jack Russell Terrier and other terrier breeds. This disease is similar to the human disease Weill-Marchesani syndrome.
PLL involves lens displacement from its normal position within the patellar fossa to the anterior or posterior chambers due to rupture of the lens zonules. Subsequent to luxation, the lens can induce secondary glaucoma and anterior uveitis.
This disease is usually bilateral in dogs, although both lenses do not luxation simultaneously and may be separated by weeks or months.
Affected dogs are often middle-aged and present with lens luxation on fundoscopic examination. Affected dogs may develop ocular hypertension and secondary glaucoma, anterior uveitis, Descemet's membrane duplication, retinal detachment or retinal degeneration and constitutes and ocular emergency with these cases.
Diagnosis is usually confirmatory on identification of the ADAMTS17 mutation by DNA testing.
A differential diagnosis would include other causes of lens luxation.
Testing of affected breeding stock and sterilization of affected dogs may minimizes incidence of this disease.
Conservative medical treatment is usually initiated in the short-term with use of miotic drugs (e.g. 0.005% latanaprost), as topically drugs may delay further anterior luxation of an unstable lens.
A bilateral lensectomy (intracapsular lens extractions) or lenticular phacoemulsification is usually required as a salvage procedure, but in valuable dogs, a sulcus intraocular lens implant is usually applied.
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