Among newborns (1st month of life) refractive error distribution is skewed toward:
In the first few years of life, the is a(n) __________ in ATR astigmatism.
A premature infant would be more likely to be ___________.
Hirsch longitudinal study reported a _________ change in refractive error ages 6/7 - 11/12.
You are seeing a school aged child (5-6) who presents with a refractive error somewhere between +0.5 to +1.24 D. The parent wants to know what the future holds for their child:
You wouldn't prescribe glasses here. This child will likely become emmetropic by age 13-14 (when their eyes stop growing)
You are seeing a school aged child (5-6) who presents with a refractive error somewhere between 0 to +0.49 D. The parent wants to know what the future holds for their child:
The child will likely become myopic at age 13-14
You are seeing a school aged child (5-6) who presents with a refractive error of <0 (myopic child). The parent wants to know what the future holds for their child:
This child will likely become more myopic.
You are seeing a school aged child (5-6) who presents with a refractive error of +1.50 D or greater (hyperopic child). The parent wants to know what the future holds for their child:
They will likely still be hyperopic at 13-14
For changes in refractive error during school years, refractive error changes occur _______ and _______ in myopes compared to hyperopes.
What is the most common type of myopia onset (of Grosvenor's classifications)?
prevalence at 5-6 is 2%
prevalence in adults is 25%
What is responsible for the progression of childhood myopia?
Axial elongation of vitreous chamber
An increase in axial length is associated with normal eye growth. For hyperopic and emmotropic children, it stops by early teens. For myopic children, it continues into:
Mid to late teens
When compared to emmetropic young adults, myopic adults have: (3)
Greater vitreous depth
greater corneal power
greater posterior lens radius
When compared to school aged males, school age females differ in that they have: (3)
more powerful lens
The earlier in life that myopia onsets, the _________ the amount of myopia developed by late teen to young adult years.
A higher rate/ speed of childhood myopia progression is associated with:
Earlier onset of myopia
What study found that children with ATR astigmatism at age 5-6 developed myopia by 13-14 vs those without astigmatism or WTR astigmatism?
The Hirsch Study also found that once myopic, ATR astigmants don't have greater rates of:
Childhood myopia progression
What treatment methods can slow myopia progression?
rigid contact lenses
What are some drawbacks to using atropine to slow myopia progression?
Parents have to administer it daily
it dialates the child's eye (to lessen accomodation)
myopia progression starts back when treatment stops
How do rigid contact lenses slow myopia progression?
They flatten the cornea -> more hyperopia
Bifocal glasses used to slow myopia progression can be used to treat ________ and ________ disorders. They are most effective in slowing myopia progression in children with a(n) ___________ at near.
Accommodation and vergence
What is a disadvantage to using PALs to slow myopia progression in children?
The lack of a line makes them harder for kids to adapt to them.
What is the general trend of refractive changes in adults?
Refractive error stabilizes (may become myopic or more myopic if they go to college)
Adult acceleration of myopia differs from childhood progression of myopia in that:
In adults, the increase in myopia stems from an increase in corneal power (vs in children, where the increase in myopia comes from an increase in axial length and lens power)
What are the chances that an entering college student with a refractive error of > +1.0 D will be myopic after 4 years of school?
What is the general trend in refractive error from age 40+?
What is the general trend is astigmatism from age 40+?
Shifts toward ATR astigmatism
The process of emmetropization requires these 2 things:
Coordinated eye growth
good visual feedback system
Treatment with spectacle correction aids in the ___________ process and decreases amblyopia.
In the visual feedback system, axial length changes based on _______ ________.
Concerning the etiology of astigmatism, one theory states that eyelid tension can steepen the _________ corneal meridian and lead to _____ astigmatism.