What does the acronym 'DK' represent in contact lens terminology?

In contact lens terminology, 'DK' refers to the diffusion constant, specifically measuring the permeability of a material to oxygen. The diffusion constant indicates how easily oxygen can pass through the contact lens material to reach the cornea. This is particularly important for maintaining eye health and ensuring the comfort of the wearers, especially if they are using contact lenses for extended periods. A higher DK value means that the lens allows more oxygen to diffuse through, which is beneficial for corneal health, as the cornea relies on oxygen from the air for metabolic processes. Understanding DK helps optometrists recommend appropriate lenses to patients based on their individual needs and lifestyle factors.