That geeks wear glasses may not be a fact, but it’s certainly received wisdom. For example, search Google Images for pictures of a “geek” and of the 13 pictures of people on the first page of results, 7 wear spectacles.
Oddly enough, this is actually a lower proportion than that of the general public which really does wear glasses: one estimate puts that figure at 64%. Of course, that’s distorted by elderly people suffering from age-related diminishing vision, so it certainly seems fair to say the stereotype of a geek is somebody more likely to wear glasses throughout their life than the average citizen.
Whether this stereotype is accurate is hard to tell without a clear definition of a geek. Whether it’s a particularly uncharitable definition (somebody socially awkward) or a kinder one (somebody with a particular obsession with a subject, often one which isn’t mainstream), there seems to be little scientific study of geekdom and eyesight.
What is more common is the link between intelligence and wearing glasses, and whether accurate or not I doubt most self-styled geeks would object to being considered as having above average intelligence.
It certainly seems the case that spectacle wearers seeming more intelligent is a deep-seated belief which takes hold as early as childhood. One study of children aged between 6 and 10 found most who were asked to judge based on nothing more than pictures considered a pictured child with glasses to be more intelligent than one without. (Interestingly they also considered spectacle-wearers to be more honest.) The pattern was consistent regardless of whether the child making the judgment wore spectacles themselves.
There’s also some evidence that this might be true. An Australian study found there was no clear link between myopia (short-sightedness) and characteristics such as being an extrovert or conscientious. But it did find a weak link between myopia and “agreeableness” and a strong link between myopia and openness. That led some to conclude that this openness was linked to having a wide range of interests, being well educated and wanting to learn new things, all of which could come across as intelligent.
Another study of children in Singapore found more intelligent children were twice as likely to be short-sighted, regardless of how much they read.
How such a link works is something of a chicken and egg situation. One seemingly logical explanation is that intelligent people and/or geeks spend a lot of time on activities which tax the eyes and could worsen eyesight. (I distinctly remember as a child being told by an optometrist that I needed to put my glasses on when working at school, reading, watching TV or using a computer, and wondering exactly when I was going to be taking them off.)
Another theory is that even where two people may have similar levels of eyesight, somebody who reads often is more likely to notice problems and thus consider it worth getting an eye examination leading to a glasses prescription.
The only theory I’ve ever seen which suggests there might be a more inherent biological cause and effect is this one (which is from somebody claiming to be a neurobiology student, writing on a site which isn’t exactly a peer-reviewed medical journal). It says that if eyesight is limited because of damage to, or underdevelopment of, the occipital lobe, the brain may compensate by putting more emphasis on the frontal lobe, which can deal with skills such as reason and decison making.
(Picture courtesy of Flickr user Archie McPhee)