French Ophthalmologist here. The part that describes how easy it is to obtain glasses without a doctor's prescription is totally false. People do need a prescription made less than 3 years ago (and optometrists do not exist here, you have to go to the doctor). As an ophthalmologist, I may not be objective on this subject; however I can confirm that I find everyday health problems in people that "just want a prescription". This can be a simple cataract, as well as a diabetic retinopathy or a glaucoma. I especially remember a 50 years old woman who had the habit to go to an optician, have her refraction measured, go to her family doctor and ask for the according prescription (with no eye exam). After 10 years without seeing a doctor, I diagnosed her with an advanced glaucoma. She was almost blind. Glaucome is the worst disease: totally asymptomatic and irreversible. Checking your eyes at least every 3 years after 40 is usually a good idea.