Optho/ENT Flashcards
Name the derivation for each part of the eye below:
1. Retina
2. Vascular and sclerocorneal layers
3. Lens
- Neuroectoderm of the forebrain
- Mesoderm
- Surface ectoderm
Development of the eye begins in the 5th week of gestation
When does the pupil become reactive to light?
30 weeks but may not respond until 32 weeks, well developed by 1 month of age
eyelid closes in response to light at 30 weeks
When is optic nerve myelination complete?
2 years old
How does innervation control the pupillary reaction?
parasympathetic innervation –> constriction
sympathetic innervation –> dilation
What does the pupillary respons to light test for?
intact afferent and efferent pathways of cranial nerve III
suggests visual function of subcortex
What does a nonreactive UNILATERAL pupil with increased size suggest?
subdural hematoma or other unilateral mass
What does nonreactive BILATERAL pupils with increased size suggest?
Late signs of HIE, IVH, infantile botulism
What does the red reflex detect?
Retinal blood vessels
Demonstrates lack of obstruction between external corneal surface and retina
<28 weeks may not have red reflex- unclear corneas and vitreos
What is leukocoria and what does it suggest?
White reflex
Most commonly caused by cataracts
Other: retinoblastoma, coloboma, ROP, retinal detachment
What is hypotelorism associated with?
HIGHLY assoc with holoprosencephaly
Others: Meckel-Gruber, T13, Williams
What is hypertelorism associated with?
Apert, Cruzon, cat-eye, CHARGE, Cri du chat, DiGeorge, Holt-Oram, Noonan, Trisomy 8
Teratogentic effects of hydantoin, isoretinoin
Describe Ptosis
upper eyelid cannot rise to normal level
Usually caused by dysfunction of the levator palpebral muscle (CN III)
AD
Cranial nerve palsy in Horner’s syndrome
5 stages of ROP
- Distinct demarcation line separatin transition of vascularized posterior retina and avascular anterior retina
- Demarcation line is thickened and elevated
- Ridge with extraretinal neovascularization and retinal vessels enter vitreos space
- Partial retinal detachment
- Complete retinal detachment- severest from
Plus disease: dilated, tortuous vessels that demonstrate advanced vascular disease, always evident before retinal detachment
s
Threshold for treatment in ROP
stage 3 with plus disease in zone I and II + 5 contiguous clock hours or 8 total clock hours
50% progress to stage 5 ROP
Risk of retinal detachment decreased to 25% with treatment
Type I prethreshold ROP
Zone I: any ROP with plus disease; or stage 3+/- plus disease
Zone 2: stage 2 or 3 with plus disease
Treat
Type 2 prethreshold ROP
Zone 1: stage 1 or 2 without plus disease
Zone 2: stage 3 without plus disease
Close observation
15% progress to type I
Prognosis in ROP- infants are at risk for?
AMBLYOPIA, REFRACTIVE ERRORS (mostly MYOPIA with severe ROP), STRABISUMUS
If ROP as neonate, increased risk of retinal detachment during adulthood
Infectious causes of cataracts
Rubella, toxoplasmosis, HSV, varicella
**In utero radiation exposure can cause _____
Cataracts
Etiology of primary glaucoma
AR
Males>females
presents at birth
caused by structural abnormality
Epidemiology of hearing loss
~2% of all infants screened will refer
~15-20% of those will have confirmed hearing loss
Most common genetic cause of hearing loss
Mutation in the connexin 26 (Cx26) gene
Causes ~20-30% of congenital hearing loss
Etiology of hearing loss
50% genetic (Cx26 gene most common)
25% acquired (develops secondary to injury to the developing auditory system in intrapartum or perinatal period)
25% unknown
What is the most common cause of nonhereditary sensorineural hearing loss?
CMV!
10-15% of babies with congenital CMV are symptomatic
60% will have sensorineural hearing loss
5-10% of asymptomatic babies develop sensorineural hearing loss
