Lens Luxation

The lens is the transparent structure within the eye which assists focusing. It is a flattened sphere which is held in place by tiny ligaments around its circumference.

In some dogs, particularly the terrier breeds, the ligaments can break down allowing the lens to dislocate from its normal position. It can fall backwards into the eye - posterior luxation - where it rarely causes discomfort or can fall forwards - anterior luxation - where it blocks the drainage of fluid from the eye allowing a build up of pressure, or glaucoma to develop. This is extremely painful and can cause permanent blindness. If the lens dislocates forward emergency treatment is required to reduce the risk of permanent damage to the eye. This usually entails specialist surgery to remove the anterior lens luxation and your veterinarian will probably refer you to a veterinary ophthalmologist for this.

What signs will the dog show?

When the lens dislocates into the anterior chamber it becomes very painful so the dog will close its eye. The eye will look red and cloudy and it is likely to have a watery discharge.

What does the surgery involve?

This is performed by specialists and the dog will require general anaesthesia. Once the eye has been prepared for surgery it is opened with an incision near or through the clear cornea and the dislocated lens is removed. The eye is closed with sutures which are absorbable and thus do not need to be removed. 

Is any post operative care required?

Your dog may have to stay in hospital for a few days after surgery for careful monitoring, treatment and rest. Once home it is vital that he/she is kept as quiet as possible and not allowed to jump up or to run up and down stairs. He/she might have to wear an Elizabethan collar. Lead exercise only is allowed for a few weeks. Remember the eye has been opened and it does take time to heal properly.

Eye medication will be dispensed and it is important that instructions are carefully followed. If you have any problems at all it is important that you call us without delay.

Will my dog be able to see again?

The aim of the surgery is to alleviate discomfort and save vision as much as possible. If the lens has been dislocated for any length of time the chance of restoring vision is reduced although hopefully some guidance vision can be saved. In earlier cases quite good vision can be maintained although it will never be as good as prior to the lens dislocating since the eye can no longer focus on objects.

Are there any complications?

Complications can occur in some cases. These include persistent glaucoma (increased pressure within the eye) despite the fact the lens has been removed. This complication can be difficult to treat successfully although some patients do well on certain eye drops.

"Complications can occur in some cases. These include persistent glaucoma (increased pressure within the eye) despite the fact the lens has been removed."

Another potential complication is retinal detachment where the retina or light sensitive surface is pulled off the back of the eye as the lens has moved forwards. These eyes often remain sightless but they are usually pain free.

What causes the lens luxation?

Weakness of the lens ligaments is known to be hereditary in several terrier breeds (e.g. Jack Russell Terrier, miniature English Bull Terrier, Tibetan Terrier) and also the Border Collie. Therefore, in these breeds if one lens has luxated, it is almost certain that the same thing will happen to the other eye at a later date. It is, therefore, important that you watch for any signs of discomfort or change of appearance of the eye and call us immediately if you are at all concerned. Occasionally the lens can luxate as a result of other damage in the eye - long standing glaucoma or severe trauma to the eye for example. In these cases surgical removal of the entire eye might be necessary since removing the lens alone would not cure the underlying disease.

How quickly does the lens luxate?

Before the lens falls out of position completely it can wobble as some of the ligaments break but a few still remain to keep it loosely in place. This is what is known as sub-luxation of the lens. The eye would still look normal to the owner, and cause the dog no pain, but a specialist veterinary ophthalmologist would be able to detect the lens instability. Some veterinary ophthalmologists like to operate on these subluxated lenses before they dislocate completely so the eye does not exhibit pain and glaucoma that can follow total anterior luxation. However others prefer to leave them until they do luxate because the potential complications are still present if the lens is operated on when subluxated. In some dogs, treatment with eye drops can reduce the risk of glaucoma while the lens is subluxated but there is no known treatment to prevent the unstable lens from fully dislocating eventually.

What happens if the lens falls backwards instead of forwards?

When the lens falls into the back of the eye it causes little or no discomfort. These cases can sometimes be monitored or treated with drops rather than requiring emergency surgery. The surgery is technically very demanding and the risk of complication greater. However the lens is not fixed in the back of the eye so it can still move around in the eye and can sometimes fall forwards, converting into an anterior luxation. This can be followed by discomfort and blindness as already described such that surgical removal is then required.

What is the prognosis?

The prognosis for all cases of lens luxation is guarded. It is a very serious ocular disease which can result in pain and blindness. Sometimes the eye needs to be removed if it has become very badly damaged and is blind and painful to the dog. In inherited cases the second eye is always at risk, and regular specialist monitoring is essential to provide the best long term outlook for the dog.

If you have any queries, please do not hesitate to contact us.