Myopia (Nurture) - Week 10

Question 1

Which regions have increased prevalence of Myopia?

Answer 1

East Asia and Eskimos

Question 2

List 5 environmental factors that influence prevalence and development of myopia

Answer 2

• increased near work
• reduced outdoor activities
• higher education levels and income
• increasing urbanization
• office-related occupations

Question 3

What relationship between birth weight and axial length was found in the Sydney Myopia Study and SCORM?

Answer 3

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

Question 4

What type of refractive error was positively correlated with birth weight in preterms?

Answer 4

Hyperopia. This was surprising given the previous results

Question 5

How does parental smoking affect myopia prevalence?

Answer 5

Reduces myopia prevalence

This doesn’t mean you should smoke though because asthma and stuff etc.

Question 6

What effect does lid fusion have on axial length?

Answer 6

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

Question 7

Is congenital cataract associated with myopia?

Answer 7

yes. Because longer axial length

Question 8

Is congenital ptosis associated with myopia?

Answer 8

Yes. And the more ptosis you have, the more myopia

Question 9

What age of Eskimos have the larger prevalence of myopia?

Answer 9

Younger generations (10-40 more prevalent than 40yrs; less than 30 more prevalent than over 30yrs)

Question 10

Who has the greatest correlation for myopia? parents vs offspring or sibling vs sibling?

Answer 10

sibling vs sibling

Question 11

How does reading influence the risk of myopia?

Answer 11

reading more than 30 minutes daily: 1.5x risk

reading at less than 30cm distance: 2.5x risk

Question 12

How does education level affect risk of myopia?

Answer 12

positive linear relationship. More education = more myopia

Question 13

Which profession has the largest prevalence of myopia out of the following?

• general population
• college students
• millitary cadets
• clinical microscopists

Answer 13

clinical microscopists

Question 14

Which of the following changes in individuals with progressing myopia?

• corneal curvature
• anterior chamber depth
• lens thickness
• vitreous chamber depth

Answer 14

Vitreous chamber depth.

Question 15

Is there an association between the risk of myopia and time spent outdoors?

Answer 15

Yes. It can have protective effects, particularly in teenagers

Question 16

Is there an association between myopia and indoor sport?

Answer 16

No

Question 17

Which has a greater effect on the risk of myopia? outdoor time or near work time?

Answer 17

Outdoor time

Question 18

How much time do myopic people typically spend on physical activity or reading?

Answer 18

They generally spend more time reading and do less physical activity

Question 19

How many hours of daily physical activity will offset how many hours of daily study?

Answer 19

1 hour of physical exercise offsets 3 hours study

Question 20

Is outdoor activity protective against myopia for under 7 year olds?

Answer 20

Yes

Question 21

How is less physical activity associated with myopia?

Answer 21

Children below 1 standard dev. of average time spent on physical activity: were 10% more likely to have myopia

Question 22

Do any studies show association between outdoor activity and myopia?

Answer 22

Yes.

Question 23

Why is outdoor viewing distance important for myopia?

Answer 23

low level accommodative demand

Flat dioptric topographies

Question 24

Is myopia seasonal?

Answer 24

less in summer by tiny amount (but no strong evidence)

Question 25

Name 5 potential reasons why better light may impact myopia risk

Answer 25

pupil constriction
lens accommodation errors 
better quality of retinal image during distance fixation
dopamine release
spectral composition

Question 26

How does an agonist for dopamine affect myopia development?

Answer 26

Protects against and prevents experimental myopia

Question 27

What affect does a dopamine antagonist have regarding myopia?

Answer 27

Blocks the protective effects of high light levels

Question 28

When exposing monkeys chronically to high light levels, how does this affect myopia prevalence?

Answer 28

87% reduction in myopia

Question 29

Name 12 environmental factors suspected to play a role in risk of myopia

Answer 29

nutrition
birth parameters
stature
outdoor exposure/light levels/physical activity/ vitamin D
visual experience/deprivation
near work
education
occupation

Question 30

Did I get lazy and just basically copy Davud’s cards for this deck?

Answer 30

Yeah, pretty much. I slightly re-worded it I guess.