Congenital displacement of the lens resulting from defective zonule formation.

Dislocation or malposition of the crystalline lens of the eye. A partial displacement (or dislocation) of the lens is described as a subluxation of the lens, while a complete displacement is termed luxation of the lens. A complete displacement occurs if the lens is completely outside the patellar fossa of the lens, either in the anterior chamber, in the vitreous, or directly on the retina. If the lens is partially displaced but still contained within the lens space, then it is termed subluxation.

Partial or complete displacement of the crystalline lens from its normal position in the eye.

(congenital ectopic lens) Displacement of the lens of the eye secondary to defective zonule formation that is present at the time of birth.

Ectopia lentis is defined as displacement or malposition of the crystalline lens of the eye. Berryat described the first reported case of lens dislocation in 1749, and Stellwag subsequently coined the term ectopia lentis in 1856 (describing a patient with congenital lens dislocation).