4 ms·

The link references the rate of myopia in South Korea increasing from 18% in 1955 to 96% in 2011. This suggests 2 things: 1. Myopia is not entirely genetic, be

by ipnon 6y ago

The link references the rate of myopia in South Korea increasing from 18% in 1955 to 96% in 2011. This suggests 2 things: 1. Myopia is not entirely genetic, because genes for myopia could not have spread to almost all Koreans from almost no Koreans in the span of 56 years. 2. Myopia is somewhat genetic, because myopia existed in a significant proportion of the pre-industrial population.

saalweachter 6y ago
Prefixing this with an acknowledgement that I totally believe there was a change in the prevalence of myopia due to changes in environmental conditions (amount of sunlight, artificial lighting, etc etc)... I am curious whether 18% was the diagnosed rate of myopia in South Korea in 1955 or the actual rate of myopia in 1955. In 1955 South Korea was a poor country; now it is one of the wealthier countries (per capita) in the world. On the one hand, it is entirely believable to me that access to eye correction is radically greater than ~70 years ago, and there was a lot of undiagnosed vision problems in 1955. On the other hand, it's also entirely believable to me that literally every 20 year old (male) was given a vision test in 1955 in South Korea, because of the War. On the third hand, it's also entirely believable to me that the vision test given was fairly easy to "pass", and that a many of the people who passed it would have a level of myopia that we would now prescribe glasses for, because hey, better vision is better.
javitury 6y ago
> Myopia is somewhat genetic That conclusion is can't be supported from the above fact alone. It could be a development disorder with a certain probability of occurrence given other non-genetic factors. Perhaps some pre-industrial people didn't get enough sun time, because they spent too time at home reading. Others had physical eye damage from work activities, etc.
mikekchar 6y ago
I have always been under the impression that myopia was caused by growing too fast as a child, leading to misformed eye balls. Basically children with too much food get myopia. Surely that fits the same data pretty darn well... I wish I had a study to point to but I heard/read this decades ago.

by ipnon 6y ago

saalweachter 6y ago

Prefixing this with an acknowledgement that I totally believe there was a change in the prevalence of myopia due to changes in environmental conditions (amount of sunlight, artificial lighting, etc etc)... I am curious whether 18% was the diagnosed rate of myopia in South Korea in 1955 or the actual rate of myopia in 1955. In 1955 South Korea was a poor country; now it is one of the wealthier countries (per capita) in the world. On the one hand, it is entirely believable to me that access to eye correction is radically greater than ~70 years ago, and there was a lot of undiagnosed vision problems in 1955. On the other hand, it's also entirely believable to me that literally every 20 year old (male) was given a vision test in 1955 in South Korea, because of the War. On the third hand, it's also entirely believable to me that the vision test given was fairly easy to "pass", and that a many of the people who passed it would have a level of myopia that we would now prescribe glasses for, because hey, better vision is better.

javitury 6y ago

> Myopia is somewhat genetic That conclusion is can't be supported from the above fact alone. It could be a development disorder with a certain probability of occurrence given other non-genetic factors. Perhaps some pre-industrial people didn't get enough sun time, because they spent too time at home reading. Others had physical eye damage from work activities, etc.

mikekchar 6y ago

I have always been under the impression that myopia was caused by growing too fast as a child, leading to misformed eye balls. Basically children with too much food get myopia. Surely that fits the same data pretty darn well... I wish I had a study to point to but I heard/read this decades ago.