Congenital Lens Opacities Flashcards
what shape are the lens? is it cellular or acellular? It is a optically _____ structure?
biconvex, acellular, optically transparent structure
how does the lens change shape?
by contraction of ciliary body
what is transparent basement membrane that surrounds the entire lens?
lens capsule
the lens capsule is mostly made up of?
collagen
where do zonular fibers insert?
at the equator of the lens capsule
what happens to the anterior lens capsule as we age?
it thickens
where are mitotic epithelial cells located?
anterior lens only
where are new fibers generated? where do they migrate to? where do they meet?
at the equator → migrate to anterior & posterior lens → meet at the sutures
name the structures of the lens from innermost to outermost
embryonic nucleus → fetal nucleus → adult nucleus → cortex → anterior/posterior capsule
most congenital cataracts are unilateral or bilateral?
bilateral
what are congenital cataracts caused by?
- chromosomal abnormalities
- metabolic disorders
- intrauterine infections (TORCH)
what findings will you find with unilateral congenital cataracts?
no additional findings
which one has a better visual prognosis?
- isolated congenital cataract
- congenital cataract with ocular/systemic cormorbidity
isolated congenital cataract
what is the most common type of congenital cataracts?
cerulean (blue-dot)
which congenital cataract is nonprogressive and presents as multiple, tiny blue scattered dots?
cerulean (blue-dot)
in cerulean cataracts, where are the blue dots scattered in?
in the lens cortex
in cerulean cataracts, what causes the bluish color?
dispersion of light
when the opacities in a cerulean cataract occur in a ring-like configuration, what is that called?
coronary cataract
how do cerulean cataracts impact visual acuity?
no effect on VA
which congenital cataract is caused by metaplasia of epithelial cells?
anterior polar cataract
which congenital cataract consists of fibrous connective tissue beneath an intact anterior lens capsule?
anterior polar cataract
which congenital presents as a sharply demarcated opacity beneath the anterior lens capsule?
anterior polar cataract
are anterior polar cataracts progressive or nonprogressive?
nonprogressive
are anterior polar cataracts unilateral or bilateral?
can be either or
how do anterior polar cataracts affect visual acuity?
can be amblyogenic due to refractive error when cataracts are unilateral
what are the refractive errors causing amblyopia in a unilateral anterior polar cataract?
hyperopic anisometropia & astigmatism
which congenital cataract can be sporadic or familial, & caused by dysplastic lens fibers that adhere to the posterior capsule?
posterior polar cataract
posterior polar cataracts can be associated with what?
- persistent hyaloid remnants (Mittendorf dots)
- posterior lenticous
- persistent anterior fetal vasculature
which congenital cataract presents as a round discoid plaque that is clearly demarcated from the rest of the lens?
posterior polar cataract
what impact do posterior polar cataracts have on visual acuity?
usually no effect on VA, unless they progress
if posterior polar cataracts do progress, when do they start to progress?
usually in middle age
what is the risk in cataract surgery for a posterior polar cataract?
high risk of posterior capsule rupture
which congenital cataract is usually bilateral & heriditary?
zonular (lamellar) cataract
what are zonular (lamellar) cataracts associated with?
- low vitamin D
- hypocalcemia
- maternal malnutrition
which congenital cataract presents as an opacification of the zone around the embryonic nucleus?
zonular (lamellar) cataracts
where are zonular (lamellar) cataracts usually found?
usually in area of the fetal nucleus
zonular (lamellar) cataracts may also present with what kind of opacity? what are they called?
linear opacities may run outwards (aka riders)
what impact do zonular (lamellar) cataracts have on visual acuity?
decreased VA is common → necessitating surgery
which congenital cataract will present with a clear area of lens within & outside of the opaque zone?
zonular (lamellar) cataracts
which congenital cataract is usually caused by a genetic mutation?
nuclear cataract
which cataract is associated with ocular abnormalities such as microphthalmia, nystagmus, strabismus, & iris hypoplasia?
nuclear cataracts
nuclear cataracts involve which structure(s) of the lens?
can involve entire nucleus or portion of the nucleus
what impact do nuclear cataracts have on visual acuity?
results in decreased VA
which congenital cataract is caused by an autosomal recessive disorder that impairs galactose utilization caused by absence of the enzyme?
oil droplet cataract
in oil droplet cataracts, what must be done to prevent severe systemic problems that will result in early death?
withholding galactose products from diet
in oil droplet cataracts, exclusion of galactose in diet can do what?
may reverse early lens changes
what impact do oil droplet cataracts have on visual acuity?
results in lenticular myopia
what congenital cataract presents as an opacity following the anterior/posterior Y suture?
sutural cataract
where are the Y sutures located?
in the fetal nucleus
are sutural cataracts progressive or nonprogressive?
nonprogressive
what impact do sutural cataracts have on visual acuity?
no effect on vision, unless associated with other lens opacities that can affect VA
what are the three congenital opacities that aren’t cataracts?
- Mittendorf Dot
- epicapsular star
- persistent fetal vasculature
which congenital lens opacity is a posterior capsule remnant of hyaloid artery?
Mittendorf dot
are Mittendorf dots progressive or nonprogressive?
nonprogressive
where are Mittendorf dots frequently located?
inferonasally on posterior lens surface
what impact do Mittendorf dots have on visual acuity?
no effect on VA
what congenital lens opacity presents as brown stellate opacities on the anterior capsule?
epicapsular star
what congenital lens opacities are remnants of embryonic vascular network?
epicapsular stars
are epicapsular stars progressive or nonprogressive?
nonprogressive
what impact do epicapsular starts have on visual acuity?
no effect on VA
what congenital lens opacity is caused by failure of the fetal hyaloid vasculature to regress?
persistent fetal vasculature
is persistent fetal vasculature unilateral or bilateral?
almost always unilateral
what is persistent fetal vasculature associated with?
microphthalmia
what is the persistence of anterior hyaloid artery & abnormal tissue proliferation (retinal glial cells)?
persistent fetal vasculature
what are the variable degrees of vascular remnants?
- isolated retrolenticular membrane
- complete stalk connecting the optic nerve to the lens
