Do you damage your eyes if your glasses are not optimally fitted?
No! Poorly fitted glasses don't have any long-term effect on the health of your eyes. However, we should distinguish between the eyes of an adult and the eyes of a child, the latter of which are still developing. If a pair of glasses is poorly fitted, then this can definitely impair the vision of children and young adults. Children are not emmetropic, meaning their vision is not ideal. A child's vision develops progressively: starting in its immediate vicinity, such as when looking at its mother, through the close-up range required later for painting or reading right up to 3D distance vision. In other words: this slight hyperopia is actually advantageous at first and is something which children ultimately gets used to with age. A pair of glasses can help children develop optimum vision. Visual defects don't damage adults' eyes – no matter if they're short-sighted, long-sighted, or if they wear the wrong glasses. Instead, your eyes 'learn' to correctly focus on different distances and to modify their visual performance, as well as possible, to accommodate the particular situation. If this happens over a longer period of time and requires greater effort from your eyes, then noticeable symptoms occur.
What are the negative consequences if glasses are not optimally fitted?
Glasses which are not optimally fitted to the wearer's eyes can lead to different symptoms. Here's a typical problem: you notice that your glasses don't provide you with unimpaired vision. This leads to a subjective deterioration of your vision. This doesn't cause damage, but it certainly strains your eyes. And it means that your eyes have to work harder. The possible consequences are numerous and include everything from headaches and neck pain, all the way to dizziness or double images. Burning or itchy eyes are another symptom. These aren't just a consequence of wearing the wrong pair of glasses. Dry air can also be the reason. However, an incorrectly fitted pair of glasses can contribute significantly to the problem.
Can you damage your eyes by wearing an incorrectly fitted pair of glasses for a longer period of time?
No, absolutely not. There are also no drawbacks if your visual performance deteriorates over time and your glasses, which had been optimally fitted, no longer provide ideal correction. You may not always realise that you're not benefiting from your full visual potential – you simply get used to this situation. Thus impaired visual performance is often only discovered by an objective source, i.e. when you're applying for a driving licence.