The world of ophthalmology, like many areas of professional medicine, can be difficult to navigate if you don’t know the terms. Use our online glossary to look up and/or familiarize yourself with the various terms you may encounter.

A failure of light rays entering the eye to converge on one focus due to irregularities in the cornea and/or crystalline lenses. Common lower order aberrations are conditions such as myopia (near-sightedness), hyperopia (far-sightedness), and astigmatism. More complex higher order aberrations are less common and occur in a much greater variety of ways.

The process by which the eye adjusts focus when you change from looking at an object far away to looking at something close up.

A very common condition that causes blurred vision, usually due to an irregular shape of the cornea which prevents light entering the eye from being focused properly on the retina.