Primary lens luxation (PLL) is a painful and potentially blinding inherited condition in dogs where the lens becomes displaced from its normal position due to weakening of the ligaments that support it. Early diagnosis is crucial, as anterior lens luxation can rapidly lead to glaucoma, vision loss, and blindness if left untreated. Here’s how veterinarians diagnose PLL:
Complete Eye Exam
The first step in diagnosing PLL is a thorough ophthalmic exam by your veterinarian. They will carefully examine the eye using an ophthalmoscope to look for signs of lens luxation, such as:
- Sudden change in pupil size or shape
- Redness, squinting, or excessive tearing
- Cloudiness or haziness of the cornea
- Visible displacement of the lens
Your vet may also perform additional tests like:
- Tonometry to measure eye pressure for signs of glaucoma
- Schirmer tear test to assess tear production
- Fluorescein staining to check for corneal ulcers
- Slit lamp exam to evaluate the depth of the anterior chamber
Referral to a Veterinary Ophthalmologist
If PLL is suspected, your vet may refer you to a veterinary ophthalmology specialist for further testing and treatment. An ophthalmologist can perform more advanced diagnostics like:
- Ocular ultrasound to examine the internal eye structures
- Electroretinogram (ERG) to assess retinal function and vision
These tests help determine the extent of lens luxation and rule out other eye conditions. Sharing any observed changes in your dog’s eyes, such as discharge, squinting, or vision problems, can also aid in diagnosis.
Genetic Testing
Genetic testing is available to screen for the ADAMTS17 gene variant known to cause PLL in many breeds. While a positive result confirms the genetic predisposition, a negative result does not necessarily rule out PLL, as other genetic factors may be involved. Screening is recommended in at-risk breeds to identify carriers and affected dogs.
Importance of Early Detection
Early detection of PLL is crucial, as anterior lens luxation is considered a medical emergency. Once the lens shifts forward, it can block fluid drainage from the eye, causing a rapid rise in intraocular pressure (glaucoma). Untreated glaucoma leads to severe pain and permanent vision loss.Posterior lens luxation, while less severe, can still cause inflammation and discomfort. Regular eye exams are recommended in at-risk breeds to detect PLL early, ideally before 20 months of age when structural changes may already be evident.In summary, veterinarians diagnose primary lens luxation through a combination of clinical signs, ophthalmic exams, advanced diagnostics, and genetic testing. Early detection is key to preserving vision and preventing glaucoma in affected dogs. If you notice any sudden changes in your dog’s eyes, contact your veterinarian promptly for an evaluation.