Primary Lens Luxation (PLL) in Dogs: Symptoms and Diagnosis

What is It?

Primary lens luxation is a condition where the transparent structure within the eye that focuses light upon the retina dislocates from its normal position.

What Causes It?

The support ligaments that hold up the lens weaken or break. Once dislocated the lens can fall forwards or backwards. Posterior luxation, backwards, will cause vision issues but typically is painless. Anterior luxation, forwards, will block the eye’s ability to drain fluids, resulting in increased intra-ocular pressure or glaucoma. The pressure this creates is extremely painful and can lead to blindness. PLL usually occurs between 4-8 years in the predisposed breeds.

The primary cause of lens luxation is hereditary. It is common in many terrier breeds especially:

Other breeds this condition are most prone to:

The secondary cause is as a result of an eye condition like inflammation, eye trauma, uveitis, glaucoma or a tumor.

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What Are The Symptoms?

  • Sudden change in eye appearance
  • Half-moon over pupil or eyes completely white
  • Pain when squinting or when eyes closed
  • Increased tears
  • Inflammation

Is it Life Threatening?

No, but it is very painful and can cause blindness. PLL should be treated immediately.

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How is It Diagnosed?

A vet will perform a medical history questionnaire, and a physical and ophthalmological exam. There are multiple eye conditions with similar symptoms so your vet will need to rule out other diagnoses. Testing may include fluorescein staining, tonometry, blood work and electroretinogram.  

What Are The Treatments?

Surgical removal of an anterior lens luxation. This surgery is often performed almost immediately as left untreated, this condition can cause blindness quickly. Other treatment may include pain management and treating secondary conditions like glaucoma, anterior uveitis or cancer.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pup’s condition, please make an appointment with your veterinarian. Or, consult a virtual vet here.