Yes, you can use an old prescription – we don't set a strict validity period for prescriptions.
If you feel you see well with your current prescription, you can use it. If your prescription is more than 2 years old, we recommend a new eye test at your local optician before you order – eyesight can change in adults, especially after the age of 40.
If you've ordered glasses from us before, we have your prescription saved from that order and can make your new glasses with the same values. So you don't need to send your prescription again.