Eye Test Glossary

Prior to each consultation your distance vision will be assessed. Patients who usually wear glasses or contact lenses may require these for the vision assessment process. In some circumstances, autorefraction may be performed to estimate your glasses prescription. This device presents a small image to each eye to estimate any errors in focus.

Measuring intraocular pressure, or the pressure within the eye, is an important component of an eye assessment. There are a range of contact and non-contact methods available to measure the eye pressure. The current gold standard to measure eye pressure is using a device known as a Goldmann tonometer. To measure the eye pressure with this device a drop of local anaesthetic and fluorescein dye is applied to the eye prior to measurement. This ensures comfort and accuracy during the measurement.

This is a non-invasive test that uses light to take images of structures within the eye. OCT if typically used to image the macula (area responsible for central vision) when assessing conditions including age-related macular degeneration and diabetes mellitus. OCT is also used to image the optic nerve; this is important when assessing for glaucoma.

Visual field testing is completed with a device that enables assessment of the peripheral and central vision and is valuable when examining for signs of glaucoma. Automated visual field machines require the patient to position their face within a bowl-shaped instrument whilst lights of varying brightness are presented. Patients are required to indicate if they have seen the light by pressing a button. The machine will then use specialised software to produce a map of the patient’s visual field and identify any areas of vision loss. Visual field testing may also be required as a component of your driving assessment.

This device using light to take images of the length and shape of the eye as a part of the work up for cataract surgery. It is important that accurate measurements of the eye are taken to ensure an appropriate intraocular lens power is selected for your eye during cataract surgery.

These devices measure the shape and curvature of the cornea. The cornea is positioned at the front of the eye and must act as a clear window to allow light through, in addition to focusing light within the eye. Corneal tomography devices scan the cornea to identify conditions such as astigmatism and keratoconus.