Myopia (Nurture) - Week 10 Flashcards
Which regions have increased prevalence of Myopia?
East Asia and Eskimos
List 5 environmental factors that influence prevalence and development of myopia
- increased near work
- reduced outdoor activities
- higher education levels and income
- increasing urbanization
- office-related occupations
What relationship between birth weight and axial length was found in the Sydney Myopia Study and SCORM?
Sydney: less than 2.5kg birth weight had shorter axial length (but birth length was assoc. with axial length in this study)
SCORM: birth weight more than 4kg, longer axial length
What type of refractive error was positively correlated with birth weight in preterms?
Hyperopia. This was surprising given the previous results
How does parental smoking affect myopia prevalence?
Reduces myopia prevalence
This doesn’t mean you should smoke though because asthma and stuff etc.
What effect does lid fusion have on axial length?
Neonatal lid fusion causes ELONGATION of the eye in macaque monkeys when animals were in the LIGHT (illuminated environment), but NO EFFECT WHEN RAISED IN THE DARK
Is congenital cataract associated with myopia?
yes. Because longer axial length
Is congenital ptosis associated with myopia?
Yes. And the more ptosis you have, the more myopia
What age of Eskimos have the larger prevalence of myopia?
Younger generations (10-40 more prevalent than 40yrs; less than 30 more prevalent than over 30yrs)
Who has the greatest correlation for myopia? parents vs offspring or sibling vs sibling?
sibling vs sibling
How does reading influence the risk of myopia?
reading more than 30 minutes daily: 1.5x risk
reading at less than 30cm distance: 2.5x risk
How does education level affect risk of myopia?
positive linear relationship. More education = more myopia
Which profession has the largest prevalence of myopia out of the following?
- general population
- college students
- millitary cadets
- clinical microscopists
clinical microscopists
Which of the following changes in individuals with progressing myopia?
- corneal curvature
- anterior chamber depth
- lens thickness
- vitreous chamber depth
Vitreous chamber depth.
Is there an association between the risk of myopia and time spent outdoors?
Yes. It can have protective effects, particularly in teenagers
Is there an association between myopia and indoor sport?
No
Which has a greater effect on the risk of myopia? outdoor time or near work time?
Outdoor time
How much time do myopic people typically spend on physical activity or reading?
They generally spend more time reading and do less physical activity
How many hours of daily physical activity will offset how many hours of daily study?
1 hour of physical exercise offsets 3 hours study
Is outdoor activity protective against myopia for under 7 year olds?
Yes
How is less physical activity associated with myopia?
Children below 1 standard dev. of average time spent on physical activity: were 10% more likely to have myopia
Do any studies show association between outdoor activity and myopia?
Yes.
Why is outdoor viewing distance important for myopia?
low level accommodative demand
Flat dioptric topographies
Is myopia seasonal?
less in summer by tiny amount (but no strong evidence)
Name 5 potential reasons why better light may impact myopia risk
pupil constriction lens accommodation errors better quality of retinal image during distance fixation dopamine release spectral composition
How does an agonist for dopamine affect myopia development?
Protects against and prevents experimental myopia
What affect does a dopamine antagonist have regarding myopia?
Blocks the protective effects of high light levels
When exposing monkeys chronically to high light levels, how does this affect myopia prevalence?
87% reduction in myopia
Name 12 environmental factors suspected to play a role in risk of myopia
nutrition birth parameters stature outdoor exposure/light levels/physical activity/ vitamin D visual experience/deprivation near work education occupation
Did I get lazy and just basically copy Davud’s cards for this deck?
Yeah, pretty much. I slightly re-worded it I guess.
