Comprehensive Eye Exams are preventative medicine: Early signs of serious health problems such as diabetes, high blood pressure, and risk of stroke can be detected in a medical complete eye exam. Most patients will receive a refractive prescription from their comprehensive eye exam, which can be used to purchase glasses or contact lenses. While many patients think the prescription is the primary reason for a comprehensive eye exam, having a medical eye exam by an eye specialist is imperative to your overall health.