What is an Autorefractor?
Tricia Christensen
Tricia Christensen
An autorefractor, sometimes called an automated refractor, is a device used during an eye exam to help determine visual acuity. The autorefractor has been in use since the 1970s. It quickly became a popular diagnostic device because of its ease of use. An optometrist or ophthalmologist uses the autorefractor to examine how the eye processes light. Refraction errors are identified with this device and can help the eye doctor determine whether a person needs prescription glasses or contact lenses.
The traditional exam with an autorefractor takes just a few seconds. The patient is seated and rests his or her chin on a chin rest. A picture is examined by one eye at a time. When the picture is ideally placed on the retina, the autorefractor prints a detailed reading that determines visual acuity and the need for any type of corrective lenses.
This exam is generally followed by an exam in which patients look at pictures and respond to the optometrist about how clear or fuzzy an image is. This examination tries several lenses to further determine prescription strength. In young children or in those who have developmental disabilities, this talking process can be difficult. In these cases, the autorefractor is considered to be the best method for determining light refraction, as it does not require verbal responses from the patient.
An autorefractor examination does not involve dilation of the pupils, but it can be a bit challenging for young children to stay still. Since the autorefractor is stationary, examining light refraction in children has remained somewhat challenging. To address the problem, scientists developed a portable autorefractor that is particularly helpful in examining children. The optometrist can adjust the autorefractor to accommodate the child, rather than making the child accommodate the optometrist.
The portable autorefractor holds great promise in the future for better eye health, because it can also allow optometrists to conduct preliminary eye examinations for those who cannot get to a doctor’s office. Mobile clinics that service low income or at risk populations can now ask an optometrist with a portable autorefractor to spend a day identifying patients who may need corrective lenses.
Additionally, some variations on the traditional autorefractor have been developed. The aberrometer is an advanced form of autorefractor that examines light refraction from multiple sites on the eye. New improvements on the autorefractor combine other eye examination functions. Autorefractors can be combined with corneal tomography measurement and wavefront analyzers to save space in the optometry office and to quicken the pace of an eye exam. These machines are relatively new, so many optometrists may not yet have them.
Tricia Christensen
Tricia has a Literature degree from Sonoma State University and has been a frequent TheHealthBoard contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.
Tricia Christensen
Tricia has a Literature degree from Sonoma State University and has been a frequent TheHealthBoard contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.
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![Autorefractors are used by optometrists.]()
By: RemziAutorefractors are used by optometrists. -
![An autorefractor can determine a need for contact lenses.]()
By: ruigsantosAn autorefractor can determine a need for contact lenses. -
![An autorefractor examination typically only requires a few seconds.]()
By: arztsamuiAn autorefractor examination typically only requires a few seconds. -
![An autorefractor is used to asses a person's need for prescription lenses.]()
By: Mat HaywardAn autorefractor is used to asses a person's need for prescription lenses. -
![Modern autorefractors are often designed to also perform other eye exam functions.]()
By: Monkey BusinessModern autorefractors are often designed to also perform other eye exam functions. -
![Portable autorefractors may be one of the tools used for a child's eye exam.]()
By: Leah-Anne ThompsonPortable autorefractors may be one of the tools used for a child's eye exam. -
![An autorefractor is used to help determine a patient's visual acuity.]()
By: fred goldsteinAn autorefractor is used to help determine a patient's visual acuity. -
![An autorefractor may be used to help determine if a patient is a good candidate for LASIK vision correction surgery.]()
By: Peter Orsaeo SrAn autorefractor may be used to help determine if a patient is a good candidate for LASIK vision correction surgery. -
![A portable autorefractor may help patients identify patients who may need corrective lenses.]()
By: Andres RodriguezA portable autorefractor may help patients identify patients who may need corrective lenses.
Discussion Comments
Unfortunately, autorefractors are not very helpful in the two populations in which they would be most useful; children and the elderly. Because of opacities like cataracts, autorefractors don't get a good "view" inside of the eye in the elderly. Children have an amazing ability to over-focus their eye muscles. This over-focusing confuses the autorefractor, and often makes the results worthless. Dilating the pupils helps to alleviate this problem. Often a simple test called retinoscopy is far more accurate in children than autorefraction. It takes more skill and time, so it is too often skipped in kids.
In different countries, the rules are different. However, you really should have a full eye examination before having any glasses made up.
The auto-refractor, while a good diagnostic tool, is often not very accurate because it only measures a small area and it is very difficult to stay absolutely still.
Normally, three results are taken from an auto-refractor and given to the optometrist as a starting point of their own refraction. The reason multiple readings are taken is because the results vary, so the average is taken.
Realistically, if a registered optician has a valid reason for making up a pair of spectacles and they are willing to justify that, if need be, to their governing body they can make whatever they want, it is their registration on the line if they are found to be negligent.
Hope this is helpful. If you have had glasses made up from an auto-refractor already and you were not given the correct guidance or advice from you optical practice, you should return to allow them to rectify their mistake and only if they are unwilling you should report them to their governing body.(for the U.K it is the General Optical Council.)
Is it legal for an optician to make/dispense eyeglasses based on the results of an autorefractor test? I know the autorefractor does not provide a full eyecare exam, but can it be used by an optician to make up lenses for eyeglasses?
@Perdido – I don't blame your little brother for being scared. I was a teenager when I had my first eye exam, and I was shaking the whole time!
I had been having headaches behind my eyes, and it was getting harder to read the chalkboard at school. My mom thought I needed glasses, so she forced me to have my eyes checked.
When I sat down in front of the autorefractor, I panicked a little. The chin rest and the forehead rest looked like a trap that would hold me still while someone rammed instruments into my eyes, and I cautiously asked the nurse what they were for before putting my eyes up to the lenses.
I was relieved to hear that all I had to do was rest my face up against them and look straight ahead. The exam wasn't nearly as bad as I feared it would be, and the autorefractor was the easiest part of it all.
I couldn't have my pupils dilated during my eye exam, because I had to drive myself back to work. The eye doctor had to rely on the autorefractor and the blurry/clear letter reading exam afterward to determine my prescription strength.
I was a bit mystified when the nurse had me look at a photo one eye at a time and then took me immediately to another room. I asked her if I had failed some sort of test, but she laughed and explained the autorefractor to me.
It is over with so quickly that you kind of have to wonder what is going on. It's amazing that something as simple as looking through a lens at a photo can tell the doctor what he needs to know.
Just last week, I took my little brother to the optometrist. He was terrified, because even though he is fifteen, he has never had an eye exam, and the thought of anyone poking around in his eye fills him with dread.
I had told him about the autorefractor, but I don't think he believed me. He couldn't see how looking at a picture of a house could show the optometrist anything.
I didn't understand exactly how it worked, but I did tell him that the autorefractor could tell how blurry or clear the image seemed to him. I think he was relieved when we got into the exam room and he actually saw that I was telling the truth.
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