Doctor Explains Extreme Short Sightedness. Source: Extreme myopia (high myopia) occurs when the eyeball becomes elongated, causing light to focus in front of the retina instead of directly on it. This change in shape doesn’t just affect vision clarity—it also alters the structure and integrity of the eye, increasing the risk of several other eye conditions. As the eye stretches, the retinal tissue and supporting structures become thinner and more fragile. This can lead to complications such as r