BS - Myopia (Nurture) - Week 10

Question 1

Name 5 environmental conditions associated with a higher prevalence of myopia.

Answer 1

Higher education and income levels
Professional or office-related occupations
Better housing
Increased near work
Reduced outdoor activities

Question 2

How do birth parameters (weight and length) affect myopia prevalence?

Answer 2

Mixed results, still unclear
<2,500g - shorter mean AL
>4kg longer AL
Birth length weakly associated with AL
However, hyperopia is also positively correlated with birth weight in preterms

Question 3

Does parental smoking affect myopia prevalence?

Answer 3

Yes, studies suggest it lowers myopia prevalence.

Question 4

What effect does lid fusion have on axial length (dark and light)?

Answer 4

Neonatal lid fusion in macaque monkeys caused elongation of the eye when maintained in an illuminated environment.
In the dark, it had no effect.

Question 5

Does congenital cataracts influence myopia prevalence?

Answer 5

Yes, congenital cataracts is assoicated with a longer axial length.

Question 6

Does congenital ptosis influence myopia prevalence?

Answer 6

Yes, more ptosis means more myopia

Question 7

Where is the region/population of greatest myopia prevalence?

Answer 7

Younger generations of Inuit Eskimos

Question 8

Is there a difference between urban and rural prevalence of myopia?

Answer 8

Urban prevalence is higher

Question 9

How does reading time and working distance affect myopia risk?

Answer 9

Reading >30 mins duration - 1.5x higher risk

Reading <30cm working distance - 2.5x

Question 10

Which of the following changes in individuals with progressing myopia?
Corneal curvature
Anterior chamber depth
Lens thickness
Vitreous chamber depth

Answer 10

Vitreous chamber depth

Question 11

Is there an association between myopia risk and time spent outdoors, or is it a weak link? Can spending time outdoors be protective against myopia?

Answer 11

There is an association.

It can be protective, especially for children 11-20 yoa.

Question 12

Is there an association between myopia and indoor sport?

Answer 12

No

Question 13

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

Answer 13

Outdoor time

Question 14

How are myopes typically for physical activity and time reading?

Answer 14

Less physically active, more time reading

Question 15

How many hours of physical activity per day will offset how many hours of study per day?

Answer 15

1h of physical activity offsets 3h of study time per day.

Question 16

Is outdoor activity protective against myopia for children under 7 yoa?

Answer 16

Yes

Question 17

Is physical activity correlated with myopia? Explain in terms of standard deviations.

Answer 17

Children 1sd below average physical activity times were 10% more likely to have myopia.

Question 18

Are there studies showing no association between outdoor activity and myopia?

Answer 18

Yes, but more show an association

Question 19

What is important about outdoor viewing distances for myopia (2)?

Answer 19

Low level accommodative demand

Flat dioptric topographies

Question 20

Is myopia seasonal?

Answer 20

No strong evidence, but reported to be less in summer by 0.10-0.20D

Question 21

Name 5 possible reasons why better light may impact myopia risk.

Answer 21

Pupil constriction
Less accommodation errors
Better quality retinal image
Dopamine release
Spectral composition

Question 22

What effect does a dopamine antagonist have concerning myopia?

Answer 22

It blocks the protective effects of high light levels.

Question 23

Consider monkeys that are maintained in high light levels. How does this affect myopia prevalence?

Answer 23

87% reduction in myopia.

Question 24

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

Answer 24

Nutrition
Birth parameters
Stature
Outdoor exposure
Light levels
Physical activity
Vitamin D
Near work
Education
Occupation