As the name implies, distance spectacles enable wearers to see distant objects more clearly. People generally start using them before they reach the age of 40. After this point the eye’s ability to change its focus from one distance to another, known as the amplitude of accommodation, is no longer sufficient to see clearly at all distances. This results in a diminished ability to focus on near objects, a condition experts call presbyopia. Different solutions are then required to meet these contrasting needs, either by switching between distance spectacles and reading spectacles, or by switching to bifocal