Definition

Lens dislocation, or lens ectopia, is a condition where the lens shifts or detaches from its proper location. The lens is considered dislocated if it is entirely outside the lens space, floating in the eye's fluid, or attached to the retina. Subluxation occurs when only part of the lens shifts, but it remains within the lens space. Lens dislocation is often caused by trauma or an accident, and sudden dislocation warrants a thorough evaluation to rule out underlying systemic diseases.

Lens dislocation can hinder daily activities, and it occurs more frequently in men than women. It can happen at any age, with the outcome depending on the severity, age of onset, and complications. Traumatic lens dislocation typically has a poorer prognosis based on the extent of the injury.

Causes

Lens dislocation can be triggered by trauma, eye diseases, and systemic conditions. Trauma is the most common cause, often resulting from direct impact to the eyeball during sports or from indirect impact to the orbit or head. Though trauma is the primary cause, other factors like systemic diseases should also be considered.

Primary eye conditions that can cause lens dislocation:

• Congenital glaucoma
• Syphilis
• Retinitis pigmentosa
• Aniridia (absence of the iris)
• Hypermature cataracts
• Myopia (high myopia)

Systemic diseases associated with lens ectopia:

• Marfan Syndrome: The most common inherited cause of lens dislocation, affecting approximately 75% of patients with the condition. Marfan syndrome is autosomal dominant and leads to lens dislocation in both eyes due to damage to the suspensory tissue.
• Homocystinuria: The second most common cause, resulting from an inherited metabolic disorder that weakens the tissue supporting the lens.

Risk Factors

• Trauma or impact to the eye or head
• Systemic diseases, such as Marfan syndrome or homocystinuria
• Family history of lens dislocation
• Other eye diseases, such as uveitis

Symptoms

The symptoms commonly experienced in lens dislocation are:

• Eye redness following trauma
• Decreased visual acuity
• Difficulty seeing objects up close
• Double vision
• Headache

Diagnosis

Your doctor will inquire about the injury mechanism, including head impact and helmet usage. If systemic or other organ disorders are suspected, additional tests will be conducted.

During the physical examination, the doctor will assess visual acuity to check for lazy eye (amblyopia). The external eye will be examined, including facial structure, corneal diameter, and the presence of strabismus (crossed eyes). If necessary, retinoscopy, keratometry, and slit-lamp examinations will be performed to check for glaucoma and anterior chamber damage, as well as to detect retinal detachment.

Further laboratory tests may be required if another underlying disease is suspected. An echography examination may also be conducted to measure the size of the eyeball.

Management

The treatment for lens dislocation depends on the position and extent of the lens movement. Prompt correction is crucial to prevent amblyopia (lazy eye). If the lens has shifted to the front of the eyeball, initial treatment involves using eye drops to dilate the iris, allowing the lens to move to the back of the eye. Glaucoma associated with lens dislocation can be managed with medications to lower intraocular pressure.

In cases of progressive but uncomplicated lens dislocation, medications might be sufficient. However, surgery is often recommended to correct vision and prevent further complications. Surgical intervention is indicated for the following conditions:

• Lens in the anterior chamber
• Uveitis caused by lens dislocation
• Glaucoma due to lens dislocation
• Deteriorating vision
• Anisometropia (significant difference in visual acuity between the two eyes)

Eye drops can help lower eye pressure, and regular follow-up examinations are necessary to monitor symptoms and eye pressure. In cases where trauma is not the cause, collaborative treatment with specialists in ophthalmology, pediatrics, and internal medicine is required.

Lens dislocation can also occur after cataract surgery. If the dislocation is minimal or mild, doctors may recommend observation to see if symptoms improve. Surgery may be needed if there is damage around the eye to correct the lens position.

Complications

If left untreated, lens dislocation can lead to amblyopia (lazy eye) and increase the risk of intraocular inflammation, such as uveitis. Additional complications may include optic nerve damage and retinal detachment, which can result in blindness if not promptly treated.

Prevention

Preventing lens dislocation involves wearing a helmet when driving and using safety goggles during activities that pose a risk of eye injury. However, lens dislocation related to syndromes cannot be prevented. Early treatment is crucial to avoid complications.

When to See a Doctor?

Immediate medical attention is required if you experience blurry eyes and redness following head or eye trauma. Additionally, if you have a family history of lens dislocation or certain systemic diseases, blurry vision may indicate lens dislocation and should be promptly evaluated.

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