Prolapsed (Luxating) Eye Lens (Ectopia Lentis) in Dogs

When the luxated lens moves towards the front of the eye, this is called an anterior luxation. If it moves towards the back, it is called a posterior luxation.

Luxation of the lens is uncommon in dogs. Dogs with partially or fully detached lenses are at risk for blindness if left untreated. Prompt veterinary attention is required for dogs with sore, red eyes.

For luxation of the lens related to an underlying condition, symptoms vary depending on the condition.

In the case of uveitis, the pupil is often constricted and the third eyelid protrudes.

In the case of cataracts, night blindness (inability to see in dim light) is often noted.

In the case of glaucoma, the pupil is often dilated and swelling or bulging of the eyeball is often noted. Glaucoma is not only a cause of luxation, but can also result from a detached lens.

There is a genetic component to lens luxation. Breeds that are susceptible include:

• Terriers, particularly Jack Russells
• Chinese Cresteds
• Chinese Shar-Pei

Dogs with pre existing eye diseases such as glaucoma, uveitis, and cataracts are at greater risk of luxation of the lens, and require ongoing monitoring. Dogs who have suffered traumatic injury directly to the eye or near the eye are also at risk.

Often, luxation of one eye indicates an issue that is likely to affect both eyes. Dogs previously diagnosed with a luxation require continual monitoring of the other eye to identify early changes.

Left untreated, a luxated lens causes damage to the other structures in the eye. Ongoing damage leads to vision loss, and in extreme cases, to complete blindness. In cases where blindness has occurred, if there is ongoing pain and swelling, surgical removal of the eyeball is sometimes required.

The lens of the eye is held in place by strands of tissue called the zonules of Zinn. If all of the zonules break, the lens comes completely free from the rest of the eye. This is called a luxation of the lens. If some of the zonules break, the lens is held loosely in place but can move around the eye. This is called subluxation of the lens.

In some cases, luxation is caused by a gene that is linked to weakness in the zonules of Zinn. In certain dogs, including terriers and others, the zonules are fragile and break easily, either as a result of traumatic injury, aging, or normal activities.

In other cases, the zonules break because of underlying conditions.

In some cases, the cause of luxation is unknown. In this case, it is called idiopathic luxation of the lens.

Diagnostic tools include:

• Physical examination
• Ophthalmologic examination

Treatment of luxation of the lens depends on underlying causes, whether the lens is partially or fully detached, and the extent of vision loss. If diagnosed early enough to retain vision and the lens is still sufficiently attached to the eye, medical management is possible. Medical management includes:

• Glaucoma medications to treat or prevent the increase of pressure inside the eyeball
• Anti-inflammatory medications
• Antibiotics
• Pain medication
• Medications to constrict the pupil to support the lens

In cases where complete luxation of the lens has occurred, where vision is impaired, and where the detached lens is causing a rise in the pressure inside the eyeball (glaucoma), surgery is required to remove the lens.

In cases where the pressure inside the eyeball is untreatable, surgical removal of the entire eyeball is sometimes necessary.

The prognosis for dogs with luxation of the lens depends on the underlying cause, the promptness of care, and the specific nature of the case. In general, the prognosis for maintaining vision is guarded, as it is difficult to prevent blindness in dogs when luxation has occurred. In cases where lens luxation has caused glaucoma, the prognosis is poor and often the eyeball must be removed.

Dogs whose breed have a known genetic predisposition to lens luxation benefit from regular monitoring of eye health. Through routine monitoring, detachment of the lens can be caught at the earliest possible stage.

In the case of lens luxation caused by eye disease, prevention is possible with regular ophthalmologic testing to catch eye diseases early and treat them quickly.

Subluxation and luxation of the lens are rare in dogs, but some breeds are more predisposed than others.

• Surgery
• Anti inflammatory medication
• Pain medication
• Glaucoma medication
• Antibiotics