Eye health and vision basics

To maintain good eye health and vision, it is important to have your eyes tested every two years, or more frequently if advised. You should seek advice immediately if you have any sudden loss of vision, eye pain, inflammation or irritation. Most eye diseases can be found during a routine eye test and treated when detected at an early stage. If you have health problems, such as diabetes, you may need to visit your optometrist more frequently to detect any complications.

What does it mean to have 6/6 vision?

6/6 (20/20) vision is your visual acuity, or the sharpness of vision at six metres from an object. Having 6/24 vision means you can see at six metres what a person with normal vision can see at 24 metres away. 6/6 does not translate into perfect vision and does not indicate other important aspects of sight such as peripheral vision, the ability to identify colours or depth perception.

What does visual acuity mean?

Visual acuity is a measure of your central vision, the ability to distinguish details and shapes of objects.

What tests are used to determine visual acuity?

Visual acuity tests simply consist of reading an eye chart. There are even simple tests using pictures that can be used to determine the visual acuity of infants or non-readers.

What options are available to correct impaired vision?

There are many safe and affordable options for those in need of vision correction. They include:

• Glasses. Perhaps the most traditional form of vision correction, glasses improve vision by bending light. They are practical, affordable and safe.
• Contact lenses. Contact lenses are often chosen for cosmetic reasons or by people with an active lifestyle. There are many different types, colours and materials, so it is best to seek advice and shop around to find the contact lenses that work best for you.
• Corrective surgery. Vision correction surgery improves sight by changing the refractive, or light bending, properties of the eye. Refractive surgery restores a person's ability to see at a moderate visual acuity, meaning that there may still be a need in some cases for glasses or contact lenses.

What will it cost?

You are entitled to free eye tests if:

• You are under 16
• You are under 19 and in full-time education
• You are over 60
• You are over 40 and have a close relative who has glaucoma
• You have diabetes or glaucoma
• You are registered blind or partially sighted

Refractive surgery is not generally available on the NHS. The cost will vary according to the type of surgery and the clinic where it is carried out.