Glenn Stok is a technical writer who researches health-related issues and shares his knowledge to inform those seeking meaningful answers.
It’s important to understand the different eye doctor professions, so you know which to use for your specific needs. This article is a review of each of the three specialties.
Here is a quick explanation of each, then I go into more detail later in this review.
Ophthalmologist: Specialist in Eye Disorders and Diseases
An ophthalmologist is a specialist educated as a medical doctor dealing with disease and injury of the eye. They also perform surgical procedures. They must complete a residency in ophthalmology in medical school and have an M.D. degree or a Doctor of Osteopathic Medicine (D.O.).
Optometrist: Prescriptions for Vision Correction
An optometrist is a prescriber of corrective lenses for eyeglasses or contact lenses. They have education in optics and is the one who figures out what prescription you need to improve your vision.
In the United States, they complete medical training before their practice. They have an O.D. degree (Doctor of Optometry), which takes four years to complete after receiving a bachelor’s degree.
Optician: Sells Eyewear to Fill Prescriptions
An optician is a health care practitioner who fills the prescription by fitting and dispensing lenses and eyewear to correct your vision. They usually have an associate's degree or an apprenticeship of two to four years.
Ophthalmologist: Doctor for Eye Disorders and Diseases
If you have any health issues or injury with your eyes, you'd want to see an ophthalmologist.
If you have a history of glaucoma in your family, it's important to get annual checkups with this type of eye doctor. As an example, my ophthalmologist diagnosed me with glaucoma and saved me from losing my sight. He prescribed drops that controlled my eye pressure.
An Ophthalmologist is a medical doctor who can treat eye diseases. That's important if you have medical issues, such as I had with glaucoma.
Ophthalmologists can also treat glaucoma with a procedure that keeps the pressure normal, so you don't need to use eyedrops. It's a special laser treatment called Laser Iridotomy. I had that done.1
Another example of an issue that requires the attention of an Ophthalmologist is if you ever suddenly have flashes and a lot of floaters. You need to get that checked fast. It could be a minor issue such as a detachment of the vitreous, the fluid in the eye.2 However, it can be more serious—such as a detachment of the retina, and that needs immediate attention.
An Ophthalmologist can determine which of these issues is the cause of these symptoms, and he or she can treat it.
Optometrist: Doctor for Vision Correction
An optometrist is the best eye doctor to go to when you want to get a vision test for a new prescription.
In the past, I used to go to an ophthalmologist to perform a vision test and write out a prescription for lenses. Then I would have it filled by a local optician who also sold me the frames. I often had issues with an incorrect lens, but I never had trouble when I had my prescription written by an optometrist.
I concluded that since optometrists are specialists with optics of the eye, they understand the patient's needs better for vision correction.
Why an Optometrist Is Best for Vision Correction
As I got older, I eventually needed progressive lenses. These are special lenses that have differing prescriptions from top to bottom. The top is for seeing far, and the bottom is for near. They are like bifocals, but without the line between distance and near. Progressive lenses change gradually from top to bottom.
The first time I had progressives prescribed, I had my ophthalmologist do it. I could never get used to the glasses.
Everyone tried to tell me that it takes time to get used to them. Don't believe that. It's wrong. If the lenses were made right, and set in the frame correctly, you wouldn't need to adjust to them.
I found out that this was the case when a friend insisted that I go to her optometrist to get a prescription for progressive eyeglasses. Her doctor considered my particular needs by asking what I did for a living.
Since I told him I do a lot of work on a computer, he specified that the lenses should be set higher in the frames. That was necessary since most of my work involved looking out the middle for nearby work. Without that consideration, the lenses would be set too low.
When one reads, one looks out the lower part. But in my case, I look out the middle of the lens since I am close to the computer. That was the first time I had an optometrist give me a vision test and write a prescription, and he understood my needs. My progressives were great from the first time I wore them. I have never had a problem with eyeglass prescriptions since then.
As I mentioned earlier, Ophthalmologists understand diseases of the eye. That is their specialty. But Optometrists know better how to determine proper prescriptions for vision correction.
Optician: Doctor for Filling Lens Prescriptions
Opticians know how to set the Position of Wear (POW) properly. That includes five different values that are important to set correctly.
For example, progressive lenses require a proper angle known as pantoscopic tilt. Ask your doctor about that. If he or she does not know what you mean, find another doctor.
Two more common settings are:
- Pupillary Distance or P.D. — Distance between the pupils.
- Optical Center or O.C. — Position that is the optical center of the lens.
Modern Opticians’ offices have up-to-date equipment for measuring these things digitally, with a precision of 0.1mm.
If you already have a prescription from a recent vision test, you can bring it to an optician to get your eyeglasses. He or she will order the lens and fit it correctly in your frame. Many opticians also sell the frames.
How Does an Eye Doctor Measure Internal Eye Pressure?
An eye doctor uses a Tonometer machine to perform an exam to measure the internal eye pressure. The exam is known as Tonometry. The device displays the pressure in millimeters of mercury (mm Hg).
There are two kinds of Tonometers:
- The Applanation Tonometer applies a small amount of pressure to the eye and measures the resistance to determine the internal pressure.
- A Non-contact Tonometer is not as accurate but is used on patients who are queasy about having something touch their eyes. This tonometer uses a warm puff of air.
In both cases, the doctor gives you numbing eye drops, so you don’t feel it.
Normal eye pressure is in the range of 12 to 22 mm Hg. Pressure higher than 20 mm Hg may indicate a diagnosis of glaucoma.3 However, some people can have glaucoma at lower pressures. That’s why it’s essential always to have a thorough eye exam by an ophthalmologist.
What's the Difference Between an O.D. and D.O. Degree?
I find many people get confused with D.O. and O.D., and some sites on the Internet mix them up too. So I decided to explain this clearly.
An Optometrist is an eye doctor with an O.D. degree. That stands for Doctor of Optometry.
On the other hand, a D.O. is a Doctor of Osteopathic Medicine. They practice medicine and perform surgery, as well as prescribe medications. That has nothing to do with being an eye doctor unless they also completed a residency in ophthalmology.
A family physician can be an M.D. or a D.O. There is not much difference except that a D.O. pays more attention to a patient’s lifestyle to determine proper care. An M.D. focuses more on treating ailments by prescribing medications.
Being a specialist in a particular field does not necessarily make one the right doctor. Patients need to know the limitations of each.
It's crucial to find a knowledgeable eye doctor in the right field. Ask your primary doctor or friends for recommendations. Then check their references, which you can do online.
- “How My Doctor Cured My Glaucoma With Laser Iridotomy” patientslounge.com
- “My Experience With Eye Floaters and Flashes and What Caused It” patientslounge.com
- Troy Bedinghaus, OD. (December 08, 2017). "How Tonometry Eye Pressure Test Works". verywellhealth.com
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2013 Glenn Stok
east on May 02, 2019:
I like the tip that you gave to choose an optometrist to give you a prescription for your glasses. My wife and I have been talking about finding new glasses, and I want to update my prescription before I get some, and it would be important for me to know that I am going to the right person. If I decide to get my prescription updated, I will be sure to look for an optometrist to do so.
kbdressman from Harlem, New York on November 07, 2016:
Thanks Glenn! And thanks for reminding me its time to update my profile! I'm actually at Touro College of Medicine now, across from the Apollo Theater in Harlem, NY.
Glenn Stok (author) from Long Island, NY on November 06, 2016:
kbdressman - Thanks for affirming the accuracy of my explanation, Katie. That means a lot coming from you since you are a premedical student.
kbdressman from Harlem, New York on November 06, 2016:
This is a great piece that's extraordinarily accurate and still easy to understand! Vision is important to our health in many ways and it's important that we see the right person for the appropriate problem. Thanks for laying this out so clearly!
Glenn Stok (author) from Long Island, NY on April 03, 2013:
Jean - I have the same problem developing with driving at night. Many of my friends who are around my age say the same thing. Losing the ability to see small print is also common as we grow older. Progressives do the same job as bifocals in the sense that they let you see far when looking out the top, and near when looking out the bottom. Progressives, however, don't have that dividing line. They progressively change from far to near as you move from the top of the lens to the bottom. Hence the name -- progressive lens.
Jean Bakula from New Jersey on April 02, 2013:
I have never worn glasses, but in my mid fifties, find I have trouble seeing at night when I drive, and cannot see little print on instructions and such. So does that mean I need bifocals? My husband went to a bad doctor who we think gave him a wrong script, and he ended up with a pair for close work, and a pair for distance. He said the bifocals made him feel headachy and nauseous. I'm afraid it will be too hard for me to begin with bifocals. What are progressives? Thanks.
Glenn Stok (author) from Long Island, NY on January 11, 2013:
Thank you to you both, Margarita and Christy, for your comments. It's common that many people don't realize the difference. Glad to know this was helpful.
Christy Birmingham from British Columbia, Canada on January 11, 2013:
What a useful read Glenn. I wear glasses and these details about the differences between the types of doctors is good to know. Vote up and useful.
MargaritaEden from Oregon on January 11, 2013:
Glenn, this is a wonderful lesson on the eye doctors, I can't believe that I always thought that all three of those specialists names is the same thing, now I know it's not true.