Your eye test explained
At Vision Express, we take vision seriously. We recommend you have an eye test at least every 2 years, or more frequently if recommended by your optician. With more than 100 different ways to test your eyes are working correctly, our opticians select the tests most appropriate for you.
The eye test not only provides an accurate assessment of your ability to see, but also gauges the general health of your eyes - and can result in early identification of other eye problems such as diabetes or high blood pressure.
- 1. Visiting the Opticians
- 2. Using a non-contact tonometer
- 3. The autorefractor
- 4. About your health and lifestyle
- 5. The retinoscope
- 6. The test chart
- 7. Using the ophthalmoscope
- 8. Associated phoria (fixation disparity) test
- 9. The slit lamp
- 10. Visual field screener
- 11. Testing your focus
- 12. Discussing your needs
- 13. Choosing your glasses
1. Visiting the Opticians
If you've never had an eye test before, rest assured that the process is very simple and thorough.
A comprehensive eye test takes approximately half an hour, and in that time your Optician will look closely at all aspects of your vision and eye health. Following your eye test, we have expert associates on hand to help you to select a pair of glasses to suit your face perfectly, or the right contact lenses for your requirements.
2. Using a non-contact tonometer
A non-contact tonometer is an instrument used by your Optician during a comprehensive eye test. The tonometer measures the pressure inside your eyes, known as intraocular pressure.
A puff of air is directed into the eye, measuring intraocular pressure based on the eye's resistance to the air. It only takes a couple of seconds to perform and can give your Optician valuable information about the health of your eye and any indicators of more serious eye conditions. Caught early, these can easily be corrected and treated.
3. The autorefractor
An autorefractor is used during an eye test, which assists your Optician in providing the best visual correction. Your Optician will use the autorefractor to examine how the eye processes light. Any refraction anomalies can help to determine if you need prescription glasses or contact lenses to correct your vision.
The autorefractor examination only takes a few seconds and is completely painless. Resting your chin on the chin rest, we will ask you to look at a picture. The autorefractor then uses a complex procedure to estimate your required prescription. This information is then used by your Optician along with other tests to determine the prescription that gives you the best standard of vision.
When the picture is perfectly placed on the retina, the autorefractor then gives an accurate reading of the eye's visual acuity and the need for any corrective lenses.
4. About your health and lifestyle
Looking after your eyes isn't just about regular visits to the Optician - it's about looking after your health and lifestyle as well. Today's sophisticated eye tests can detect signs of underlying health problems such as diabetes or high blood pressure, and a regular eye test may mean that these problems could be spotted much earlier.
If you have an active lifestyle, your Optician may be able to help you find the right kind of eye correction. For people who enjoy sports, contact lenses may be more suitable than glasses, and guidance can help you make an informed decision.
5. The retinoscope
Another tool which is used to help determine your final prescription is the retinoscope. It measures the refractive error of your eye to determine the proper prescription for any corrective lenses that might be needed. By observing how the eye processes a beam of light, your optician can determine if you suffer from myopia (nearsightedness) or hypermetropia (farsightedness) or if you have an astigmatism.
The test is only takes a few seconds, and is a precursor to further testing to determine the exact prescription you may need to correct your sight.
6. The test chart
The test chart is probably the most familiar piece of equipment used by your Optician to check your eyesight. The most common chart is the Snellen chart, which is a series of letters of differing sizes, ranging from the largest at the top to the smallest at the bottom.
During an eye test, you will be asked to read from the chart to determine the visual acuity of your sight. If you have good eyesight, you should be able to read near the bottom line clearly without any corrective lenses. If you cannot read these lines, corrective lenses may be required.
7. Using the ophthalmoscope
The ophthalmoscope is used to examine the retina at the back of your eye. This will determine the condition of the blood vessels and the head of the optic nerve, and can also detect any changes in the health of this area that may indicate underlying diseases such as diabetes, high blood pressure or macular degeneration
Another way of examining your retina is by using a slit lamp bio-microscope and volk lens, which your Optician uses in combination to see a magnified image of your retina.
8. Associated phoria (fixation disparity) test
This determines if your eyes are working well together and how much correction may be needed to balance your eyesight.
You will be asked to look at a panel and say whether the bars appear to be in line both horizontally and vertically. If they appear out of line Your Optician will decide whether or not this needs correction with a prism in the lenses of your glasses.
9. The slit lamp
The slit lamp is an illuminated microscope used mainly to examine the outer surface of your eyes, eyelids, lashes and surrounding areas Your Optician can then look at the condition of the cornea, sclera, conjunctiva, the iris and the lens. This checks the condition of the outer surface of the eye and can be used to look for abnormalities or scratches.
The slit lamp examination is particularly important for contact lens wearers, as the lens sits directly on the surface of the eye. It is used to check the fit of contact lenses, and allows us to monitor any changes in your eyes due to contact lens wear. Your Optician may recommend glasses as a more comfortable option in the presence of anomalies that cause discomfort when wearing contact lenses.
10. Visual field screener
The visual field screener is used to determine your field of vision and locate any 'blind spots' within that field. During the test, you will be asked to look at a spot in the centre of the machine and respond lights flashing around this central target. This test is repeated several times in both eyes.
11. Testing your focus
Most people who have trouble focusing on either near or distant objects can have their eyesight easily corrected by prescription lenses. To find out if you need corrective lenses, your Optician will test your ability to focus on both close-up and distant objects.
You are asked to focus on an object at a set distance. By placing various strength lenses in front of each eye, we can tell from your response if the lens makes the object appear more or less in focus. The correct prescription for each eye can then be determined.
12. Discussing your needs
Throughout the examination, your Optician will clearly explain each test to you and how your eyes are responding. Once all the tests have been completed, you will then have time to ask any questions you may have and the results of the eye test will be explained. You may be recommended corrective lenses to improve your vision. Your Optician will then discuss your options with you - for either prescription glasses or contact lenses or possibly both depending on your lifestyle and needs.
Your Optician will also give you advice on how you can keep your eyes healthy and answer any other health queries concerning your eyesight that you have.
13. Choosing your glasses
Once your eye test has been completed, your results will be handed over to an associate to help you choose the right glasses. At Vision Express we have a wide range of frames and lenses to choose from, suiting many different style and budgets. We will help you choose the correct frame and lenses for your prescription.
It is important that you choose a pair of glasses that you feel happy with, and we will make any minor alterations to the frames to ensure that they fit properly and are comfortable to wear.