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Best and worst opticians stores

Best places to have an eye test

By Joanna Pearl

Article 2 of 7

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Best places to have an eye test

We reveal the best places to have an eye test, and essential advice on understanding your eye test and prescription.

Eye testing is vital: as well as making sure you get the right glasses, it can help you identify serious health problems. 

An eye examination is not just about getting new glasses. It’s a chance to spot potentially serious eye and health problems such as glaucoma and diabetes.

It usually takes 20 to 30 minutes - possibly longer. The optician will assess your history, for example, whether this is a routine check-up or if you've had any problems, and about your general health and the work and any hobbies you do.

Take control of your consultation

Be proactive in describing any issue you're having to the optician. You'll be helping them to give you the best appointment:

  1. Be clear about any unusual symptoms you’ve had, such as headaches or flashes of light. While an optometrist should ask about these, it’s best to be upfront if you’ve experienced any problems, so they can follow up with more questions.
  2. Don’t assume anything you’ve mentioned to the technician has been passed on to the optometrist. As our research shows, sometimes communication between the person carrying out pre-tests and the optometrist can be poor. Mention anything of concern directly to the optometrist.
  3. Don’t be afraid to ask questions, for example about the results of each test. A good optometrist will talk you through what they’ve found, even if it’s just to say that your eye health is stable.
  4. If you find an optometrist you trust, stick with them, especially if you have any complicated eye problems. They can keep a record of your retinal photos or scans and track any problems as they develop.
  5. If there’s a problem with your prescription, go back to the original opticians to get it sorted rather than seeking a second opinion, as it will be easier to resolve.

Common eye tests

Below we've listed some of the more common tests that your optician or other staff members will carry out.


Is used to determine the strength of your glasses so your optometrist can see if your prescription has changed. You’ll be asked to hand your specs over and they will be placed on a machine – this often happens in the pre-testing before the appointment.

Pressure check (tonometry)

This test for glaucoma and can be easy to spot, as lots of optometrists use a method that blows puffs of air in your eye.

Visual fields check

Look at your peripheral vision. This may be done with a technician before the appointment and involves you clicking a button as you see dots of light flash up in the edges of your vision.


Can be used to automatically estimate your prescription. You’ll be asked to look into a machine and most likely see a picture that will move in and out of focus.

Prescription check

Is the part where the optometrist will show you a series of lenses and ask you questions such as ‘clearer with or without’ or ‘sharper in 1 or 2’.

A slit lamp

Is a microscope with a bright light used to look at the front and sometimes back of your eyes. You’ll place your chin in a chinrest and be asked to look straight ahead or at the optometrist’s ear.


Can be used to look at the inside of your eye, particularly the retina. Normally, the lights are turned down and the optometrist will come in close with a light and check your eyes in a variety of positions such as straight ahead, up, looking to the left and so on.

Digital retinal photography

Is where a picture of the back of your eye is taken and stored, to create a record of your eye health, so that changes over time can be monitored. Your optometrist should show you the images later in your appointment – they are likely to look like orange/red circles with blood vessels running through. Some practices may also offer Optical Coherence Tomography ‘OCT’ 3D scanning of the eyes.

Usually available at an extra charge.

Reading your prescription

The numbers in a prescription relate to your right (R) or left (L) eye. 

A plus (+) sign under ‘Sph’ (Sphere) means that your eye is long-sighted, and a minus (-) that your eye is short-sighted. 

The number (for example +2.5) is the correction prescribed (your prescription) and is measured in ‘dioptres’. 

‘Cyl’ (Cylinder) describes astigmatism found – how far your eye is more rugby ball shaped than football shaped. It can be written as either a plus or minus number. ‘Axis’ is a number between 0 and 180 to describe the angle in degrees of any rugby ball effect.

Small amounts of variation in prescriptions from different opticians are perfectly normal (even the same optician testing you on a different occasion) due to the subjective answers you give. However, this variation should not normally be greater than the equivalent of two steps in the power of the lens (0.50 dioptres). 

Large variations may occur as a result of diabetes, and this would need further investigation.

Eye testing at home

A home (domiciliary) sight test can be carried out free in your own home by an experienced optician.

You can have this service if you qualify for a free NHS sight test but can't get to a high street optician store because of a mental or physical disability or mobility problems. 

This includes having new glasses fitted and provided, as well as eye testing.

This can be arranged through your local NHS (GP) or NHS Direct if you live in England or Wales and NHS Helpline in Scotland.

It can be a really important way of helping someone housebound to stay living well at home, preventing accidents such as trips and falls due to poor eyesight.

For more information, go to the Federation of (Ophthalmic and Dispensing) Opticians (FODO) website.

The best place to get your eyes tested

We've surveyed thousands of Which? members about their experiences to find out which companies are rated best and worst for eye tests, including the booking process, timeliness and thoroughness.

Many people choose to have their eyes tested in one place, but buy their glasses elsewhere. Our survey results show that this can be a good strategy, as the companies that score well for buying glasses don't necessarily get the same high scores for eye testing. For example, Asda is ranked second of nine by people who bought glasses from the company, picking up five-star ratings for price, value for money and special offers - but it’s only eighth of 12 for eye testing.

Specsavers’ customer ratings put it near the middle of the table for both, with the store environment letting down otherwise good eye-testing ratings.

We know it's difficult for patients to judge whether they're getting a good consultation including the right tests. That's why, in October 2017, our researchers had undercover eye tests at up to four branches of each optician across England and Wales.

We found that - on 13 out of 30 visits - our expert panel of optometrists rated them poor or very poor, using measures such as 'adequate history-taking' and 'accurate prescription'. 

Be your own expert. See our lowdown on the eye tests you should expect, and five tips to help you ask the right questions, below the table.

Our table below shows each of the key brands and independents scored in our survey for eye testing.