External and Anterior Disease Flashcards
normal axial length, K value, and corneal diameter in newborns and adults
axial length: 14.5-15.5 newborns, 23-24 adults
K: 52 newborns, 42-44 adults
corneal diameter: 9.5-10.5 newborns, 12.0 adults
general trend of refractive state of eye from birth to adulthood
start hyperopic, increase in hyperopia until 7 years old, then slowly become more myopic until emmetropia occurs (about 16 years)
when is the pupillary light reflex present
31 weeks gestational age
normal visual acuity at birth? what are the stages to adult vision, and when does 20/20 vision occur?
- pupillary light reflex 31 weeks gestation
- 20/400 at birth
- blink to light a few days after birth
- maintain eye contact 6-8 weeks
- smooth pursuit 3-4 months
- 20/20 @ 3-5 years
what is dystopia canthorum and what syndrome is it associated with?
lateral displacement of both inner canthi and lacrimal puncta such that line connecting upper and lower puncta crosse cornea; Waardenburg syndrome
what is cryptophthalmos?
failure of eyelid structures to form; skin covers orbit. usually cornea is also abnormal. can be seen in Fraser syndrome (also w/ syndactyly and GU anomalies)
lateral widening of the palpebral fissure with downward displacement of the lower half of the eyelid?
euryblepharon
types of epicanthus
tarsalis: fold more prominent superiorly
palpebralis: fold equally prominent sup and inf
inversus: more prominent inferiorly
supraciliaris: arises from eyebrow
findings in BPES? surgery?
blepharophimosis-ptosis-epicanthus-inversus syndrome
blepharophimosis: narrowing of hor and vert PF
ptosis
epicanthus inversus
may also have telecanthus
ptosis repair is usually w/ frontalis sling as there is usually poor LF
hypertelorism v telecanthus
hypertelorism is increased distance between medial orbital walls (which also causes widened interpupillary distance). telecanthus is increased distance between medial canthi, which is always present in hypertelorism but can also be due to primary skin/soft tissue abnormalities in the absence of hypertelorism
name the law: premature bony suture closure prevents perpendicular growth but permits parallel growth
Virchow’s law
most common autosomal dominant craniosynostosis? involved gene and chromosome? most common features?
Crouzon syndrome; FGFR2 on chromosome 10. tower-skull. hypertelorism, proptosis, and inferior scleral show. intelligence usually normal. NO syndactyly or other extracranial manifestations
How do the following parameters change from birth to adulthood?
a. lens power
b. keratometry
c. refractive state
d. axial length
e. pupil size
f. CCT
g. angle depth
h: iris color
i. IOP
j. distance of EOM insertions to limbus
a. decreases dramatically (about 35 at birth)
b. decreases (52 to 43)
c. become more hyperopic until 7, then less hyperopic until about 16 when emmetropia is reached
d. increases (15 to 23.5)
e. increases
f. decreases for first 6-12 months to ~553, then increases to ~573 and stabilizes @ ~12 years old
g. deepens
h: darkens (accumulates pigment in iris stroma and melanoctyes in first 6-12 months)
i. increases (lower in infants than adults)
j. 2mm less at birth, 1mm less @ 6 months, equal to spiral of Tillaux @ 20 months
T or F: astigmatism is common in infants?
True (and then often regresses)
T or F: the NLD is not fully canalized in many newborns?
True (although usually is asymptomatic)
