Congenital Anomalies Flashcards
When is the most vulnerable period for eye malformation
24-40 days
What is anophthalmia
COmplete abscence of ocular tissue
SOX2 gene mutation - lethal
What is cyclopia
Formation of single globe in midline with absent optic nerve
Lethal
What is synophthalmia?
Two incomplete globes join in midline
Lethal
What is microphathlmia? Causes? Gene?
Small disorganised globes
Patau’s trisomy 13
Foetal alcohol sydnrome
Rubella
Toxoplasma
CMV
CHX10 mutations
What is nanophtahlmia
Small eyes with normal lens - hypermtropia
What is cryptophthalmia
Abnormal eyelid development andn fission - abnormal eye developement
Cornea and AC absent
REtina and ON normal
What is megalocornea?
Corneas larger than 12mm at birth
Congential glaucoma
Marfan’s Alports
Downs
Albinism
Whta is microcornea
corneal dimater < 10mm
What is axenfeld rieger syndrome?
Autosomal dominant
Congenital malformation of the anterior segment
Thinning of cornea, polycoria
Displaement of schwalbe’s line anteirorly
Mutation of PITX2
FOXC1
What is aniridia
Absence of neuroectoderm derived iris pigement peihtleium, sphincter, dilator muscles - absence of pupil
Associated with Wilm’s tumour
What is ocular albinism
Defective melanin production
IRis pigment dficiency
Poor stable vision
Where does iris coloboma occur
Inferonasal
Failrue of optic fissure to fuse on day 33
What is CHARGE syndrome?
Coloboma
Heart defects
Atresia of nasal choanae
Retardation of growth
Genitourinary defects
Ear abnormalities
What is Peter’s abnormality? Causes?
Abnormal cleavage of the developing cornea form the lens vesicle at day 33
Abnormal development of central, paracentral or entire corneal endothelium and Descement’s
Part 1 cornea does not adhere to lens
Type 2
Bialteral cataracts with keratolenticular stalk bridge connecting lens and cornea
PAX6 gene mutation
Exposure to ethanol and isotretinoin in utero
What can cause cataract in utero?
Malnutrition
Infection
Rubella (pre 6 weeks gestation)
Genetic predisposition
What is perisitent hyperplastic primary vitreous?
Fibrovascualr stalk links posterior lens nad optic nerve
What is the cloquet’s canal?
Persistant hyaloid artery
Associated with premature low weight
What is the mittendorf dot?
Failure of anteiror segment of hyaloid artery connection to lens to degenerate seen as plaque on the posterior surface of lens capsule nasally
What is tunica vacsulosa lentis
Developing lens supplied by hyaloid artery and capillary meshwork on posterolateral surface of lens seen at birth if not completely regressed
What is Bergmeister’s papilla
Failure of posterior section of hyaloid artery to degenerate leaves fibrous tuft and membrane attached ot optic disc
What is the optic pit?
Locallised defect in optic fissure on ONH allows dysplastic retina to herniate into subdural space through defect in lamina cribrosa
Allows CSF to cause serous RD
USually loacted temporally or inferiorly
