Dislocated Eye Lens in Dogs

The lens of the eye is held in place by ligaments of a sort, called zonules (bands that attach the lens to the retina) and vitreous (fine fibers that hold the lens in place). When lens displacement takes place, the condition can cause pain or sometimes have no physical impact at all. However, the vision of your dog will always be affected. Lens luxation must always be addressed because of the risk of serious complications like glaucoma, or because the lens luxation could be the result of an underlying condition such as a tumor. A dislocated lens is often recognized as an inherited condition in the Terrier breed (Smooth, Wire Hair Fox, Jack Russell, Miniature Bull, Sealyham, Skye, Tibetan, Manchester, Scottish, and Welsh), and in Shar-Peis, Welsh and Cardigan Corgis, Collies, and the Brittany Spaniel.

• A dislocated eye lens is also known as lens luxation. The lens of the eye serves to allow the light and images to reach the retina. Alterations to the lens, such as in a congenital form, trauma or disease will bring changes to the vision of your dog.

Some canines may not show any symptoms of lens luxation; this can depend on the location of the dislocated lens. If you see that your dog is sticking closer to you and appearing to be looking for guidance or support, or if he is displaying any of the signs below a visit to the veterinary clinic is imperative.

• The eye may be bulging (this could be due to fluid build up)
• There could be pain in the eye causing your dog to paw at it, or rub his face against the floor or objects
• The eye could be very red
• There may be tearing
• The eye or eyes could look abnormal
• The eyelid could twitch
• The vision is very likely reduced

In some instances, lens luxation is found only during a routine check up where the eye is examined (typically a posterior luxation as described below). It should be noted that lens luxation can occur in both eyes concurrently.

Types

Posterior lens luxation

• The lens moves backward into the vitreous cavity (the space in the eye where the vitreous fibers are)
• This type of dislocation rarely brings pain
• Ocular inflammation and glaucoma can cause it to happen
• It occurs mostly in older dogs

Anterior lens luxation

• The lens moves forward into the anterior chamber of the eye
• This condition causes intraocular pressure leading to glaucoma because it is blocking drainage from the eye
• It can also cause swelling of the cornea
• Inherited lens luxation typically results in an anterior move

If a case of dislocated eye lens is left untreated, blindness can result. As well, your pet could be experiencing a fair amount of pain that you are not aware of. This is a condition  that must be dealt with as soon as possible in order to obtain the best possible outcome for retaining vision or avoiding further damage to the eye.

• Ligaments and fibers weaken, allowing the lens to move
• Genetics may play a factor
• Older dogs may experience a degeneration in the eye which allows for lens movement
• Trauma can cause lens luxation
• A tumor within the eye can cause the lens to move
• Inflammation may be influential
• Enlargement of the eye globe because of glaucoma can cause the lens to shift
• Cataracts can result in changes within the eye that lead to luxation

The veterinarian may be able to see that your canine family member has a dislocated eye lens by the clinical signs present upon first view; she will also take into consideration the breed disposition to lens mobility, the age of your dog and whether he has ocular problems already. 

Diagnostic tools that will give the veterinarian a closer look are the ophthalmoscope (viewing the back of the eye), the gonioscope (to look at the chamber between the iris and the cornea) and the tonometer (measures intraocular pressure). She may see the degeneration of vitreous strands and changes of symmetry within the eye chamber. The veterinarian will analyze the urgency of the situation (and it is most often urgent) due to complications like obstruction of fluid flow in the eye and retinal tears.

Treatment depends on whether the dislocated lens has moved to an anterior or a posterior position.

Anterior lens luxation

• Surgery to remove the lens is the protocol due to the intense pain involved
• Antibiotics and corticosteroids are prescribed to follow
• With severe pain and permanent blindness, which may happen when the luxation has done much damage before discovery, enucleation is performed (removal of the eye)

Posterior lens luxation

• Surgery is much more difficult and pain is not usually present, therefore, the lens is left where it is
• The eye will be monitored carefully for changes or if pain occurs

In the case of lens removal, a hospital stay is necessary. After the ophthalmologist feels that your pet can go home, he will be released with instructions to rest and stay quiet for several weeks. This means leash walks only and no running or jumping. Vision may be improved after the surgery, but the potential complication of retinal detachment or glaucoma is a reality.