Ectopia lentis

Ectopia lentis refers to subluxation or dislocation of the lens of the eye secondary to dysfunction or disruption of zonular fibers. It is most commonly due to trauma. The commonest atraumatic etiologies are Marfan syndrome and homocystinuria.

Pathology

Etiology

• trauma
• systemic and syndromic disorders
  • Marfan syndrome
    • typically upwards and out
    • most common spontaneous cause ²
  • homocystinuria -  typically downwards
  • Weil-Marchesani syndrome
  • Ehlers-Danlos syndrome
• hereditary (or isolated) ectopia lentis
• primary ocular disorders
  • aniridia
  • intraocular tumors
• infective conditions, e.g. syphilis

Marfan syndrome, homocystinuria and Weil-Marchesani syndrome account for the vast majority of non-traumatic cases.

Radiographic features

Ultrasound

Sonographic features of lens malposition differ based upon the degree of luxation as follows ⁵:

• subluxation
  • unilateral deviation of the lens margin posteriorly into the anechoic vitreous body
  • the contralateral margin remains fixed adjacent to the iris
• complete luxation
  • the lens assumes a dependent position in the vitreous
  • demonstrates free mobility with eye movements

Associated findings include:

• traumatic cataract
  • increased echogenicity of the lens is suggestive
• vitreous hemorrhage

Treatment and prognosis

Complications

An anterior dislocation/subluxation carries greater complications than a posterior one. Such complications include:

• acute glaucoma
• corneal injury
• iridal injury