Dislocated Lenses in Children
When the lens is not in its normal position, it is said to be dislocated. Subluxated (or subluxed) lenses are partly dislocated. Luxated (or luxed), or ectopic, lenses are completely detached from the ciliary body; they are free in the posterior chamber (Fig 23-7), or they have prolapsed into the anterior chamber. The amount of dislocation can vary, from slight displacement with minimal iridodonesis (tremulousness of the iris) to severe displacement in which the lens periphery is not visible through the pupillary opening. Lens dislocation can be familial or sporadic. It can be associated with gene mutations that specifically affect the eye, with multisystem disease, and with inborn errors of metabolism (Table 23-4). Lens dislocation can occur with trauma, usually involving significant injury to the eye, but this is not common. Spontaneous lens dislocation has been reported in aniridia, buphthalmos associated with congenital glaucoma, and congenital megalocornea with zonular weakness (due to mutations in latent transforming growth factor beta-binding protein 2 [LTBP2]).
Khan AO, Aldahmesh MA, Alkuraya FS. Congenital megalocornea with zonular weakness and childhood lens-related secondary glaucoma—a distinct phenotype caused by recessive LTBP2 mutations. Mol Vis. 2011;17:2570–2579.
Figure 23-7 Lens dislocation into vitreous.
Table 23-4 Conditions Associated With Dislocated Lenses
Isolated Ectopia Lentis
In simple ectopia lentis, the lens is displaced superiorly and temporally. The condition is usually bilateral and symmetric. Most commonly, it is inherited as an autosomal dominant trait. Onset can be at birth or later in life. Glaucoma is common in the late-onset type.
Some patients with heterozygous mutations in FBN1, which cause Marfan syndrome (discussed later), do not have the systemic findings associated with this syndrome and have only ectopia lentis.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.