Those who have never experienced difficulties with their vision in their lifetimes can count themselves lucky. The rest of us, myself included, will need to consult an eye doctor to assess and address their compromised vision. But there are a few different types of eye-care professionals who can examine your eyes to determine if you need glasses or contact lenses, and each have different qualifications and specialties.

Opticians are licensed health care professionals who fill prescriptions for glasses or contacts. Their expertise is technical, and they identify the specifications of corrective lenses prescribed for patients. Compared to medical doctors, they are similar to pharmacists, though dealing with lenses instead of prescription drugs.

Optometrists are licensed medical professionals who deal specifically with vision and eye care. To pursue a career in optometry, one must complete an undergraduate degree, and then attend a specialized school to obtain their doctorate in Optometry. Optometrists can diagnose and treat common visual impairments, plus some eye diseases like cataracts, but the amount of treatment they provide varies depending on jurisdiction.

When people use the term “eye doctor,” they could be referring to either an optometrist or an ophthalmologist. Ophthalmologists are medical doctors. Like optometrists, they complete an undergrad degree, but then they attend a medical school to receive a doctorate in Medicine, followed by a four- to five-year residency in ophthalmology (qualifications vary in different countries). Ophthalmologists have the most complete knowledge of the eye and its structure, and they specialized in eye pathology and eye surgery. Ophthalmologists can perform the same assessments as optometrists, but optometrists are not trained in treating eye pathologies.

So which do you need? If you need a new pair of glasses or contact lenses, an optician can take care of that for you. If you need to have your vision checked, you can visit an optometrist, who can prescribe corrective lenses for you. If you have more serious medical problems with your eyes, you would go to your family doctor, who would then refer you to an ophthalmologist for a more thorough examination.

The difference between eye care specialists comes down to training—more education means a greater depth of knowledge, and accordingly, a greater ability to assess more serious problems. Each has their function, and each is devoted to an equally essential component of professional visual care. Knowing which is which can help you know where to turn when your vision becomes an issue.