Flashcards in BCSC Peds Deck (569)
How many phases of growth of the axial length of the eye occur?
3 phases (1st -- 4mm, 0-6mos; 2nd -- 1mm, 2-6 yrs; 3rd -- 1mm, 5-13 yrs)
What is the normal newborn axial length of the eye?
15-17mm (vs. 23-24mm adult)
What is the normal newborn corneal horizontal diameter?
10mm (vs. 12mm adult)
What is the normal newborn corneal radius of curvature?
6.6mm-7.4mm (vs. 7.4-8.4mm adult)
Is mild corneal clouding normal in newborns?
Yes, and it is expected in premature infants.
What is the central corneal thickenss at birth?
0.96mm (--> 0.52mm at 6 mos)
Does the power of the pediatric lens increase or decrease over the first years of life?
Are infants hyperopic or myopic at birth?
What happens to the refractive state of the eye from 0-7 yrs?
What is emmetropization?
The process of growth of the eye to resopnd to and cancel out refractive error in children in order to reach emmetropia
What are the average palpebral fissure measurements in infants?
18mm wide, 8mm high
Is normal IOP in children higher or lower than in adults?
lower, > 21 is considered abnormal in children
What is the difference in the insertion sites of the of the EOMs relative to the limbus in children vs. adults?
2mm closer to limbus in newborns, 1mm closer at 6 mos, similar to adults at 20 mos
Is vertical gaze fully functional at birth?
no, usually not fully functional until 6 mos
What is the direction of retinal vascularization?
Centrifugal, with the optic disc as the center; does not reach temporal ora serrata until 40 wks
What are the two major methods for quantifying visual acuity in preverbal infants/toddlers?
Preferential looking (PL) and Visually evoked potential (VEP)
What type of visual acuity test is constituted by Teller acuity cards?
What is the average visual acuity of newborns?
20/600 by preferential looking, 20/400 by VEP
When is 20/20 acuity reached in children?
by 3-5 yrs of age
What is dysraphia?
the failure to fuse (e.g. choroidal coloboma)
What is hypotelorism?
Reduced distance between the medial walls of the orbits. It is associated with over 60 syndromes.
What is hypertelorism?
lateralization of the entire orbit (leading to an increase in both the inner and outer intercanthal distances) It occurs in over 550 disorders.
What is the theoretical cause of hypertelorism?
early ossification of the lesser wing of the sphenoid, which fixes the orbits in the fetal position
What is exorbitism?
It is defined in two different ways by different clinicians: 1) prominent eyes due to shallow orbits; 2) increased angle of divergence of orbital walls
What is telecanthus?
Increased distance between the inner canthi (more a measurement of the canthus itself and soft tissue than of the orbit, distinguishing it from hypertelorism)
What is secondary telecanthus?
Telecanthus in the presence of a normal inter-pupillary distance
What is dystopia canthorum?
lateral displacement of both the medial canthi and the lacrimal puncta such that the line connecting the upper and lower puncta passes over the cornea rather than sclera
What is cryptophthalmos?
The skin passes uninterrupted from the forehead over the eye (usually malformed) to the cheek and blends with the cornea of the eye
What is a common association of eyelid colobmoma?