Can wearing the wrong strength glasses cause irreparable eye damage or just headaches etc?

Wearing the wrong strength glasses is unlikely to cause permanent or irreparable damage to your eyes. While it can lead to various symptoms and discomfort, including headaches, eye strain, blurred vision, fatigue, dizziness, or difficulty focusing, these issues are temporary and usually resolve once the correct prescription is used. It's still important to see an eye doctor for proper diagnosis and to rule out any underlying conditions.