Development of the Ametropias Flashcards
Hirsch Longitudinal Studies in California:
______ in refractive error b/w ages 6-7 to 11-12 yrs old
Linear change
Hirsch Longitudinal Studies in California:5 or 6 yr old children w/+1.50 D or more hyperopia will ________ at age 13-14
still be hyperopic
Hirsch Longitudinal Studies in California:
Majority of 5-6 yr olds w/refractive error of +0.50 to +1.24 will be ________ (-0.49 - +0.99 D) at age 13-14
emmetropic
Hirsch Longitudinal Studies in California:
Most children entering school with refractive errors of 0 to +0.49 D will be ____ at age 13 or 14
myopic
Hirsch Longitudinal Studies in California:
Children who are myopic at age 5 or 6 will become ______
more myopic
Changes in Hyperopes Compared w/Myopes
-Among school aged children, greatest changes in refractive error occurred in _____
myopes
Refractive change is _____ when a child cross from hyperopia into myopia
faster
Onset of Myopia in Youth:
What are the four types of myopia (Grosvenor’s Classification of Myopia)?
- Congenital
- Youth-onset
- Early adult-onset
- Late adult-onset
Describe Youth-Onset Myopia.
What is the prevalence at 5-6 years of age? 15-16?
Most common type of myopia
Onset: school-age years
Onset for females for about 2 years earlier than males
5-6 yrs of age–> 2%
15-16 yrs of age –> 20-25%
Once myopia appears in childhood, it ____ until the middle to late teens
increases
Emmetropic children b/w age 6 and 14 yrs show:
1)
2)
3)
Increase in axial length
Decrease in crystalline lens thickness
Decrease in crystalline lens power
Axial Elongation of vitreous chamber is responsible for ________
myopia progression
During childhood, myopia occurs from axial length increase –> refractive power _____
decreases
_____: Axial Length Increases
Myopia
Myopic vs. Emmetropic Young Adults:
1)
2)
3)
1) Greater vitreous depth
2) Greater corneal power
3) Greater posterior crystalline lens radius
School-Aged and Young Adult Females vs. Males:
1)
2)
3)
1) Shorter eyes
2) Steeper corneas
3) More powerful crystalline lenses
The earlier in life the onset of myopia occurs, the ____ amount of myopia developed by late teens to young adulthood
increases the
Higher rate of childhood myopia progression is associated with?
the earlier onset of myopia
Myopes vs. Nonmyopes 1) 2) 3) 4)
1) Spend more time reading/lots of near work
2) Have occupations that require near work
3) Better reading ability
4) Have more years of education
Shorter reading distance is also associated with __________
greater myopia progession
Once myopic, _____ astigmats do NOT have greater rates of childhood myopia progression
ATR
Children with ____ at 5-6 developed myopia by 13-14 vs those without (or WTR)
ATR
These factors are associated with Higher Rates of Childhood Myopia Progression: 1) 2) 3) 4) 5) 6)
1) Earlier onset age/higher initial amount of myopia
2) Near-point esophoria
3) Temproal crescents and other myopic fundus changes
4) Higher intraocular pressure
5) Greater amount of time spent reading and doing other near work
6) Less time spent on outdoor activities
What are some pharmaceutical agents that control progression of Myopia?
Atropine and Pirenzepine
What is the purpose of Atropine?
Effects the development of retinal ganglion cells
Why is Atropine are unpopular with patients?
1) Complete Cycloplegia
2) Photophobia from dilation
3) Possible allergic reaction
What is the major downfall of Atropine treatments?
Upon stopping treatment, Myopia progression ACCELERATES
What are non-pharm methods for controlling Myopia?
1) Rigid Contact Lenses
2) Bifocal Spectacle Lenses
3) Progressive-addition Spectacle Lenses (PALs)
This form of myopia control is most effective in lower myopia progression rates for children with esophoria at near.
Bifocal Spectacle Lenses
_____ can be used for certain accommodation and vergence disorders (accommodative insufficiency, convergence excess)
Bifocal Spectacle Lenses
The rate of myopia progression in Bifocals is ____ than in Single Vision Lenses
lower
What is purpose of giving children with esophoria at near Bifocal Spectacle Lenses?
Want a near addition power to shift near phoria to ortho/low exo range
