Glasses prescription
The automatic readings make the subsequent subjective fine-tuning quicker.
A quick starting point for your glasses prescription
Autorefractor: objective refraction measurements
An autorefractor measures how your eye focuses light. In a few seconds, it provides objective starting values for sphere, cylinder and axis. Your final glasses prescription is determined through further measurements and your own assessment of how clearly you see.
Understanding the procedure
Objective measurement and subjective fine-tuning
The device projects a test image into the eye and analyses the returning light to calculate short-sightedness, long-sightedness or astigmatism.
Accommodation, the eye’s ability to adjust its focus, can affect measurements, particularly in children and young adults. Retinoscopy, testing with cycloplegic drops or subjective refraction may therefore be needed.
- Measurement
- Sphere, cylinder and axis
- Contact
- Non-contact
- Duration
- a few seconds
- Result
- Objective baseline
Used where needed
What does the measurement help us assess?
An autorefractor provides a starting point for several types of eye examination.
Initial examination
If the cause of reduced vision is unclear, these measurements help assess how much a refractive error contributes.
Changes over time
We can record changes in short-sightedness, long-sightedness and astigmatism.
Children
Suitable devices provide useful indications. Reliable refraction in children may require drops that temporarily stop accommodation.
Step by step
That's how the measurement works.
You do not need to read letters or make choices.
Position
Rest your chin and forehead and look at the target in the device.
Letting the device focus
The device automatically performs several measurements per eye.
Check plausibility
We consider light scatter, the eye’s surface, pupil size and any clouding.
Fine-tuning the prescription
A vision chart and trial frame help determine which correction gives the best everyday vision.
Understanding the results
A reading is not yet a prescription for glasses.
Dry eyes, contact lenses, accommodation, small pupils and clouding can affect objective readings. Repeated measurements and comparison with previous results help interpretation.
Children can hide undetected long-sightedness by focusing very strongly. Drops that temporarily relax this focusing response allow a more reliable refraction measurement.
Well prepared
How to prepare for your visit
- Bring your current glasses
- Specify contact lens type and wearing time
- Follow the agreed break from contact lenses before a fitting
- Allow extra time for dilating eye drops in children, if needed
Frequently asked questions
Clear, concise answers.
Will I get a glasses prescription straight after the test?
Not from the automatic reading alone. A reliable prescription usually requires subjective testing and medical interpretation.
Is the measurement suitable for children?
It provides quick indications. Depending on age and findings, refraction with pupil-dilating or accommodation-relaxing drops may be more accurate.
Why do my values fluctuate?
How you feel that day, dry eyes, accommodation, contact lenses and testing conditions can cause small differences.
Medical note
This page cannot replace an eye examination. Your symptoms, history and findings determine which tests are useful and how their results should be interpreted.
Medical basics
Sources and further information.
Related topics
All non-surgical eye care services