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

A dislocated lens can move into the front (anterior) or the rear (posterior) of the eye, and may be primary (inherited) or secondary (occurring due to another condition)
Lens luxation can block drainage of the eye's fluid and quickly lead to painful glaucoma or retinal detachment
Surgical removal of the lens is often the best option, but management strategies may be effective in some cases
Causes include uveitis, genetics, age, viruses, glaucoma, parasites, injury, exposure to irritants/toxins, and cancer
Diagnosis is by ophthalmologic exam
Good prognosis depends on early detection
Surgical removal of the eye is a common result if other treatments do not work to control pain and/or preserve vision

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A closer look: Prolapsed (Luxating) Eye Lens (Ectopia Lentis) in Cats

Signs of lens dislocation in cats may be subtle. Cats may shake their heads or paw at their eyes. Symptoms vary in severity with time. Late stage symptoms are more severe and pronounced than early symptoms.

Lens luxation may be categorized according to where the luxation is occurring (posterior or anterior) and whether it is primary (present from birth) or secondary to another existing condition.

While uncommon in cats, lens dislocation warrants prompt medical attention. This is a painful condition that can cause blindness without timely detection and treatment. With early intervention vision may be spared. Referral to a veterinary ophthalmologist as quickly as possible is recommended for the best outcome.

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Risk factors

Glaucoma may develop secondary to lens luxation and lead to additional symptoms.

These symptoms include

Hiding

Lethargy in Cats

Light sensitivity (photophobia)

Bulging eye

Dilated Pupils (Mydriasis) in Cats

Constricted pupils

Unequal pupils

Blindness and Loss of Vision in Cats

Vision loss is usually apparent only when both eyes are affected and primarily manifests in unfamiliar surroundings:

Bumping into things
Reluctance to move

Possible causes

Uveitis, or inflammation of iris, can lead to a dislocated lens

Potential causes of uveitis include

Feline Infectious Peritonitis (FIP) in Cats Feline Herpesvirus 1 (FHV-1) Infection in Cats Feline Leukemia Virus (FeLV) Feline Immunodeficiency Virus (FIV) Cat Scratch Fever (Bartonella Infection) in Cats Glaucoma in Cats Cataracts in Cats

Eye injury

Exposure to toxins

Eye irritants

Congenital anomalies

Cancer of the eye

Senescence (age-related degeneration)

Main symptoms

Symptoms are usually sudden in onset and include

Eye discharge

Squinting (Blepharospasm) in Cats

Red eyes

Swelling of the eye

Cloudy Eye (Corneal Edema) in Cats

Iris trembling

Lens trembling

Abnormally positioned clear part of the lens

Testing and diagnosis

Diagnosis is usually made by a primary care veterinarian after thorough physical exam and ophthalmic exam including:

Fluorescein stain of the cornea
Intraocular pressure measurement (tonometry)
Schirmer tear test

Referral to a veterinary ophthalmologist may be recommended. If lens luxation is found to be a secondary condition to existing glaucoma, urgent treatment is required. Glaucoma is very painful and can result in loss of vision or the entire eye.

Steps to Recovery

Treatment depends on the type of luxation, and emergency therapy for glaucoma (if present) is the priority. Anterior lens luxations are treated with:

Surgical removal of the lens
Surgical removal of the eye
Anti-inflammatories
Treatment for underlying conditions like glaucoma and/or uveitis

The best way to manage a posterior lens luxation is controversial. Medications may provide better retention of vision than surgery in some cases, especially when uveitis is the underlying cause. Treatment may not be necessary or is targeted at the underlying cause.

Dislocation of a lens is irreversible, often leading to glaucoma, which affects cats long-term. With lens removal surgery, glaucoma can sometimes be managed with medication only, but often the eye must be removed to achieve permanent resolution of pain. Prognosis after eye removal is good.

If the underlying cause of lens dislocation is cancer, prognosis depends on staging and treatment of the tumor.

Prevention

There is no specific prevention for lens dislocation. The condition itself is not contagious to other cats, but some underlying causes are (viruses such as FIV, FeLV, FIP; parasites such as T. gondii). Some of these infections can be prevented by vaccination, keeping cats indoors, and regular veterinary care. In congenital cases, prevention is not possible.