Primary lens luxation in dogs

Primary lens luxation is a relatively well-understood condition that affects the lens of the eye, and can affect various different species of animals including dogs. The eye’s lens is the transparent area behind the pupil that helps to allow light to enter the eye and focus it in the back of the eyeball, and this lens is held in place by small, blood and oxygen-rich strands around its edges.

In dogs with primary lens luxation, the lens moves from its set position and is no longer held firmly in place by the strands, and instead floats freely to either the back or the front of the eye.

If the lens floats to the back of the eye, it can cause damage to the nerve-rich, sensitive areas of the retina, which can in turn lead to other issues such as retinal dysplasia or detachment, and later, glaucoma.

If the lens floats to the front of the eye instead, this can lead to the eye taking on a discoloured blueish appearance because of the water trapped within it, which can also again lead to glaucoma due to the increasing pressure placed on the eye by the fluid.

Regardless of whether the lens itself slips to the back or the front of the eye, if left unchecked, the condition can cause blindness and also a lot of pain.

Why does primary lens luxation occur?

Primary lens luxation in dogs tends to be a hereditary condition, which is more common in some breeds than others. Terriers of all types are slightly more prone to the condition that most other breeds, with the Jack Russell being the breed most likely to develop the condition. Dogs suffering from the condition or with a known history of it within their bloodlines should not be used for breeding.

Primary lens luxation does not always have a hereditary cause however; it can also occur as a secondary complication of various other eye disorders and conditions, such as glaucoma, cataracts, and any other eye problem that may affect the stability of the strands that secure the lens in place, causing them to break loose.

Symptoms and diagnosis

Primary lens luxation in dogs can be hard to spot until it becomes quite pronounced, as the condition tends to develop quickly after it begins. Initially, the eye in question may appear to be a little red and inflamed, and your dog may show signs that it is bothering them. This is often confused with other conditions such as allergies and hayfever, which can mean that the condition is not properly diagnosed until it becomes quite advanced.

As the condition advances, the pain and discomfort of the condition can lead to your dog becoming depressed and generally flat and uninterested in the things that they usually enjoy, and the redness and irritation of the eye itself will become progressively more pronounced.

Left unchecked, the pressure in the eye itself will continue to build and press upon the optic nerve in the back of the eye, which can then become irreversibly damaged and lead to blindness. By this point, there is usually a visible blue-grey coloured tinge over the cornea as well.

When the lens detaches completely, a diagnosis of primary lens luxation is usually self-evident, but during the earlier stages of the condition, your dog may need to be referred to a specialist ophthalmic veterinary surgeon in order to get a firm diagnosis before the lens actually detaches fully.

What can be done about it?

If the condition is caught during the early stages, it may be possible to manage the condition with medication; however, in the vast majority of cases, the best option for treatment is the removal of the lens itself in order to allow the dog to retain their vision. It is important to note that as well as eventually leading to blindness, primary lens luxation is very painful, and so treatment should not be delayed once a diagnosis has been reached.

The removal of the lens of the eye will almost certainly need to be performed by a specialist veterinary ophthalmologist, as special skills and equipment that are not found in the average general practice are required.

The post-operative care for lens removal is also intensive, and will require an inpatient stay immediately after the surgery, followed by several follow-up visits to check the progress of the eye after the dog has been sent home.

In some severe cases, the whole eye may need to be removed; however, dogs usually adjust well to life with only one good eye, although this does require a little extra care and attention.

Can primary lens luxation be prevented?

Until the beginnings of primary lens luxation become evident, nothing can be done to prevent the condition developing. However, a dog that has suffered from the condition in one eye is more likely to go through the same problem with the other eye later on, and so in these cases, the lens of the other eye may also be removed as a preventative measure.

Genetic testing can also be performed to identify the potential risks of the condition in any given dog or their potential offspring, and if evidence of the markers for the condition are found, the dog should be monitored carefully and not used for breeding.