Opticians work with optometrists or ophthalmologists to design and fit corrective lenses for patients. These lenses include glasses and contact lenses, as well as low-vision aids (magnifying lenses) and ophthalmic prosthetics (artificial eyes), depending on the patient’s needs and the instructions given by the optometrist or ophthalmologist. Opticians make adjustments to the devices to ensure comfort for the patient, such as tightening or loosening glasses frames. While opticians are trained to read the prescriptions provided by the eye doctor, they do not test vision, write prescriptions, or diagnose or treat any eye conditions.