c Flashcards
what is coloboma and what is the type of coloboma
Coloboma is the imcomplete closure of the embryonic fissure
types of coloboma:
- lid, iris, lens, retina, onh,ciliary body, choroid
what is lid coloboma
congenital, and it vary from small marginal notch to a full thickness absence of the entire lid margin (1/3 to 1/2 )
- its common in upper lid and at the junction of middle and middle 3rd of upper lid
- astigmatism is common
what is the management plan for lid coloboma
medical:
- corneal protection - artificial tear and oiltment, moist chamber bandages, bed time patching
- amblyopia management
surgical: patch lid tgt
- defect small w/o corneal exposure / obstruction of visual axis = delay surgery till 3-4 yo
what is a iris coloboma and ssx
it is the failure of embryonic fissure to close in 5th week of gestation. “keyhole” pupil
typically located at inferonasal quadrant
ssx(includes/ may): photophobia in bright condition and glare, visual distortion and monocular diplopia
in PA 3/4 iris will move and constrict towards the notch.
mx of iris coloboma
- special cl: that cover the keyhole shape pupil(round looking), improve cosmetic appearance of the eye as well as reducing light sensitivity
- surgery (option for some) - sew iris together correct pupil share and reduce light sensitivity (coloma region = sensitive)
what is lens coloboma
- flattening of equator of the lens in an area of absence of zonular fibers.
- vx may be affected because of change in lens shape caused by notch / dent
- may have some catact - causing blur, misty vision, colour appearing dull and glare in vision
*big notch = vision uncorrectable
best visualised in dilated eyes and may be incidentally diagnose as they are almost always asymtom
mx of lens coloboma
rx - treat w correction lens
- severe case (-) correct manifest refraction = consider lens extraction with iol placement to prevent amblyopia from developing *zonular abnormalities may exist and complicate surgery
general mx of coloboma
-no medication and surgery can cure and reverse this and make eye whole again
-correct rx with spx/cl
- monitor for amblyopia
- treat eye condition present with coloboma e.g cataract (lens) / arise from coloboma
- use low vision
- genetic counselling
what is megalocornea and its association
anterior segment dysgenesis
is the HVID or 13mm or larger, bilateral and non-progressive
its x-linked recessive (90% males affected)
associated with marfan syndrome, ehlers - danlos,down syndrome
what is the objectives of megalocornea
normal al, fundus and onh,
reduce vitreous chamber and deep anterior chamber
normal vision and iop
- no symptom
complication of megalocornea
- astig at birth
- presenile cataract - complicated surgery as zonular fibre is weaker with normal lens
- ectopia lentis
- glaucoma
- retinal detachment
assessment and plan of megalocornea
congenital glaucoma (chronic poag) - trabescular meshwork not well developed
plan: education and reassurance
what is microcornea
its a bilateral, HVID of 10 or smaller
autosomal dominant
objectives of microcornea
associated with hyperopia, and shallow anterior chamber, normal vision
assessment and plan for microcornea
- risk of high iop - due to narrow angle
plan - routine glaucoma(aacg) screening
what is aniridia and its association
bilateral absence of the iris, total/ small stump of the iris base (iris hypoplasia), autosomal dominant
associated with: ectopia lentis, cataract, foveal and onh hypoplasia, nystagmus, conjunctivalization of peripheral cornea
ssx of aniridia
glare, poor va (6/60 or worse), dry eyes
assessment and plan for aniridia
check for glaucoma.
plan: cosmetic cl, low vision aid, sunglasses, artificial implantable iris, genetic counselling
what is albinism
melanocyte are present but do not produce melanin.
its autosomal recessive.
white hair, pale skin, pink eye.
ssx of albinism
poor vision (worse than 6/120)
high myopia and astig
nystagmus
macular hypoplasia
poor rpe fn
photophobia
assessment and plan of albinism
handle px w meticulous care - dim as possible
-low vx aid, genetic counselling, dark sunglasses, good protection again UV - easily sunburnt
what is heterochromia irides
asymmetric colour of the 2 iris
can be congenital(AD) /secondary to disease process
what is the assessment of heterochromia irides
ddx from fuch heterochromia cyclitis, siderosis, iris melanosis, iris melanoma
plan for heterochromia irides
photodocumentation, px education and reassurance
