glossary

Optical coherence tomography (OCT) is a noninvasive imaging technology used to obtain high resolution cross-sectional images of the retina. OCT is similar to ultrasound testing, except that imaging is performed by measuring light rather than sound. OCT measures the retinal nerve fiber layer thickness in glaucoma and other diseases of the optic nerve.

Combination of the curvatures of the front and rear surfaces of a lens, measured in diopters.

Eyecare professional, designs and adapts eyeglasses in accordance with measurements specific to each wearer. Professional who makes and adjusts optical aids, e.g., eyeglass lenses, from refraction prescriptions supplied by an ophthalmologist or optometrist.