Monday, July 25, 2011

Laser surgery for myopia early in life may create reading problems after 40

Shortsightedness, or myopia, seems to be endemic in urban populations. The National Institutes of Health suggests that myopia cannot be prevented, and that neither reading nor watching television causes myopia. I find that doubtful, as reading is a rather unnatural activity, and there is evidence that myopia is significantly associated with amount of reading at early ages.


Trying to avoid reading early in life would not be a highly recommended Paleolithic-mimicking choice, except for those who later decide to live among hunter-gatherers. (In spite of our romantic views of hunter-gatherer life, it is very rare to see an urbanite do this outside the context of anthropological studies.) Education requires a lot of reading, and without education in urban environments one is likely to end up suffering from other diseases of civilization. Diabetes, for example, is strongly and inversely associated with education level in urban environments.

Also, keeping up with friends on Facebook, without which life as we know it now could go on, requires a lot of reading and writing.

A different theory, often associated with Cordain, is that myopia is due to consumption of industrial carbohydrate-rich foods. Interestingly, according to Cordain and colleagues, myopia is typically accompanied by higher stature, a finding that is supported by empirical evidence. The idea here is that industrial carbohydrate-rich foods promote abnormal growth patterns during developmental stages, which arguably include abnormal growth of the human eye and its various structures.

Avoiding industrial carbohydrate-rich foods during developmental stages is feasible, but currently very difficult given public health policies that strongly promote the consumption of some of those foods, during development stages, as healthy choices (e.g., cereals). In part as a result of those policies, and also due to budget constraints (those foods tend to be generally cheap), industrial carbohydrate-rich foods are frequently served as meals in schools.

Okay, now to the main topic of this post. Let us say a person has myopia, should he or she fix it surgically?

As one ages, the ability to read at a short-distance (as in reading from books, or from a computer screen) goes down, because the ability to focus on short-distance objects becomes impaired. This phenomenon is called presbyopia, and is also associated with excessive reading. Therefore it could be called a disease of civilization as well. Most college professors at the level of Associate Professor and higher I know (that is, older folks, like me) have developed it, sometimes as early as in their late 30s.

In the general population, normally presbyopia sets in between 40 and 50 years of age, requiring the use of "reading glasses" afterwards … except for those with myopia. This is sometimes called the “myopia payoff of presbyopia”. People with myopia are often able to read well, without the help of glasses, after presbyopia sets in. The reason is that myopia essentially opposes presbyopia at short distances.

Someone with myopia will still have it after presbyopia sets in, and thus will have difficulty seeing at long distances, but will frequently be able to read well at short distances.

So, if you undergo eye laser surgery (the most common type) to correct myopia early in life, you may create reading problems after 40.

P.S.: A friend of mine who has been studying this tells me that eye problems in general are caused by avoidance of indirect sunlight. I am planning on looking into this more deeply in the future.


Valtsu said...

Kaisu Viikari has written some interesting books on this subject. Panacea is the largest one, also available as a free pdf:

She thinks that we haven't been evolved to read and reading leads to spasm of ciliary muscle. Migraine chapter is quite interest IMO.

Arthur said...

I'm not throwing away my glasses yet, but after a couple of months of trying Todd Becker's suggestions I'm pretty sure that my eyesight has improved:

David Isaak said...

I never had to use reading glasses until three years ago (age 54). My vision deterioration came on suddenly, after a huge work project that kept me at the computer 8-12 hours a day for four months.

My vision is improving gradually, however, and I don't always need reading glasses any more.

I credit this to the fact that I recently started suplementing with Vitamin A. I didn't start the Vitamin A for better eyesight (an article by Chris Masterjohn insisting that D should not be supplemented without A convinced me), but it is a much-appreciated side-effect.

allison said...

I underwent a radial keratotomy in my early 20s. My eye sight was just fine until I hit 45, at which point everything went haywire. I now have an astigmatism which is very difficult to correct with glasses. So, the cost of having roughly 20 years of improved vision will be about twice as many years of worse vision.

Ned Kock said...

Hi Valtsu, thanks.

Ned Kock said...

Hi Arthur. Even without trying, I can tell you that Becker’s suggestions make a lot of sense. What he proposes is what one would expect based on the idea of compensatory adaptation:

Ned Kock said...

Thanks for sharing your experience David and Allison.

Tim said...

I do have myopia at the age of 35. I've had it for a long time now. I probably read less than the average guy. I'm tall so that fits with me. I'm sceptical though that my myopia would be caused by carbohydrates. I've always had allergies and food intolerances and not until now I've realized this is pretty bad and that the gut needs to be fixed. Maybe malnutrition could cause myopia? I'm also sure I've had a bunch of stress even as a kid because of the issues with allergies and intolerances. I wonder if cortisol can be an issue?

I often see kids at age 5 or so with glasses. Not sure if they have myopia or not, but it seems these problems are getting more common. I'm sure these 5 year old kids haven't got it because they read too much.

Also dogs get myopia and they sure are not reading too much.

Ned Kock said...

Hi Tim. The connections of myopia with carbs and reading were the ones that I’ve been able to find in the literature. I do agree with you that this condition is probably complex and multi-factorial, and also on the rise.

Today’s 5-year-olds tend to do a lot more things that are similar to reading (e.g., game-playing on computers or consoles) in terms of their effect on eye strain.

Do you have a reference for the issue of dog myopia?

Againstthegrain said...

It wouldn't surprise me at all if myopia is also related to other "industrial" facial bone structure abnormalities, such as underdeveloped upper and lower jaws (leading to malocclusion), vertical facial growth instead of horizontal growth, deviated septum and other airway/sinus/allergy conditions, ears that stick out, etc.

No one said...

a quick literature search turns up a lot of studies saying myopia rates are higher for females in the US and Europe-- example,

I wonder if this is partly due to diet differences? Women are probably more likely to abstain from red meat, be on high-carb, high-grain "diets"; soy consumption is mostly by women...

Tim said...

I read about myopia in Barry Groves' book Trick and Treat. He refers to this paper:

theodora said...

Ive had myopia since I was 8, got my first conacts maybe by age 10..Im sure wearing contacts for 20 years is worst than having laser surgery, but I always felt like surgery would end up causing some damage later in life (since there's not many people aged 80 right now who had it to tell us whats going on!)..
But, the reason Im commenting, is on the nutrition issue: recently I was in an argument with a raw vegan (never do that about anything obviously!) who insisted that by being raw and vegan myopia can actually "go away"..U be the judge of that, but she also had some studies to refer me to..I never looked up anything just cause I know its not true..By this I mean that we can probably find studies connecting any type of diet with something about myopia..Im certain it has nothing to do with it though, its more of a genetics and lifestyle combination in my opinion..
But thats just me..

Doug McGuff, MD said...

Another thing that many fail to consider is that if you have LASIK and later develop cataracts (another inflammatory condition of the modern western diet) you may not have enough corneal depth left to undergo cataract surgery/lens replacement.

Dr. Curmudgeon Gee said...

i read there's a recent study that shows sunshine during youth would prevent myopia.

i just wonder if sunshine also helps presbyopia for adults?