Among those who know me well I have a reputation as a bit of a philistine. In my 37 years on this planet, I've read just two novels and didn't even open the set texts for my English literature O level (which I failed). The truth is, I've always struggled taking in the written word, and view the expression 'reading for pleasure' as a contradiction in terms. With such a studious aversion to reading matter, I remember feeling rather hard-done-by to find myself short-sighted and in need of glasses at the age of 13. My own experience did seem to be one in the eye for the notion that short-sightedness is the result of bookishness.
Recently, I decided to research the causes of short-sightedness (myopia). Populations with no system of formal education have very low rates of myopia (typically 0-2 per cent). This is in stark contrast to Westernised cultures, where virtually everyone is put through the mill of education, and short-sightedness afflicts between 25 and 35 per cent of people. However, other evidence suggests that the link between reading and myopia is not as clear as it may seem.
In some populations around the world, rates of myopia are very low, despite the presence of compulsory education programmes. Also, research has found that living in an urban environment is associated with a high risk of myopia even in individuals who have had no formal education. Taken as a whole, the research suggests that seeing reading as the prime cause of myopia is a bit, well, short-sighted. It is possible that the discrepancies in susceptibility to myopia may be due to genetic differences. Yet studies also show that when groups migrate from primal living to a more urbanised existence, rates of myopia shoot up within a single generation.
One obvious place to look is diet - and processed carbohydrates are a potential trouble spot. One effect that sugars and starches (such as bread, rice, pasta and cereal) have is to stimulate the production of insulin, and a related compound called insulin-like growth factor 1 (IGF-1). Too much IGF-1 can stimulate excess growth of the eyeball during development - the fundamental defect in short-sightedness. Interestingly, in populations where rates of myopia are low despite formal education, the diet is bereft of processed carbohydrates. Also, myopic individuals are more susceptible to conditions associated with the excessive consumption of sugar or starch, such as diabetes and dental decay.
Carbohydrate is important in the diet, but my advice would be to get the bulk of this in the form of non-grain foods that tend not to disrupt the body's chemistry. Green leafy vegetables, fruit, nuts, seeds, and beans and lentils all fit the bill in this respect. While conventional dietetic wisdom makes claims for the health-promoting effects of a diet rich in starchy staples such as bread, pasta and cereal, I see this as an act of blind faith.