Bump and blur

Anterior dislocation of an intraocular lens

There are two types of traumatic lens displacement (aka ectopia lentis):

• Dislocation — anterior or posterior displacement of the lens resulting from complete disruption of the lens zonule fibers.
• Subluxation — results from incomplete disruption of the lens zonule fibers.

The following questions relate to lens displacement in general (not just implanted intra-ocular lenses).

Risk factors for lens displacement in the context of minimal trauma include:

• Marfan’s syndrome (upwards)
• Homocystinuria (downwards)
• Tertiary syphilis
• Previous intra-ocular lens insertion (e.g. cataract surgery)
• Pseudo-exfoliation syndrome (see this video at RootAtlas.com)

History

• Symptoms —
  monocular diplopia or visual distortion with subluxation
  marked visual blurring with dislocation.
• Presence of risk factors (see Q2)
• Any associated injuries (ocular or otherwise)?

Examination

• Visual acuity — decreased
• Slit lamp exam —
  edge of a subluxated lens can be seen when the pupil is dilated.
  Iridodonesis — trembling or shimmering of the iris after rapid eye movements in lens dislocation.
• Look for associated ocular and other injuries. Look for evidence of risk factors (e.g. Marfanoid appearance)

Remember that ocular ultrasound is useful for detecting lens subluxation/ dislocation. There is an excellent brief video showing a dislocated lens at RootAtlas.com.

Management of lens displacement involves:

• immediate ophthalmology consultation
• treatment options vary from observation to surgical removal  and replacement depending on the location of the dislocated lens and associated eye injury.