Myopia or shortsightedness is where rays of light are focussed in front (or ‘short') of the retina rather than on it leading to blurry vision. It is easily corrected optically but high myopia can cause many physical problems as the eye is usually larger than normal which causes the focussing short fall – the retina is too far away, if you like.
Myopia is described as pathological when you get up to the doubel digits on your prescription and is linked to an increased risk of a form of macular degeneration, glaucoma and retinal detachment. The larger sized eye means the retina is streched thin over a larger area and so is more fragile and prone to damage.
This study showed that the longer your eye the less likely you are to have all forms of diabetic retinopathy (mild, moderate, severe). It's rather interesting as it flies in the face of almost every other condition. The authors didn't speculate why they through this might be the case but it will undoubtedly lead to more research as an estimated 1-2 billion people have myopia and 300 million have diabetes worldwide.