Diagnosing refractive errors

Visual acuity examination. This measures the ability to see objects at different distances (close/far). Test lenses are used to achieve the best grading.

Visual acuity with cycloplegia. Drops are used to paralyse the muscle responsible for adjusting the lens to check real grading. This test is very useful in children. It causes temporary itching when it is applied, and the dilation of the pupil, which lasts 12-24 hours, can cause light sensitivity, meaning driving is not recommended on the same day. 

Complete ophthalmological examination, including back of the eye, to rule out complications associated with refractive errors. 

Corneal topography. This is a non-invasive test that takes just seconds, and shows the shape of the cornea, the eye’s main natural lens.