Glossary NCLE Exam 2023 Questions and Answers

Glossary NCLE Exam 2023 Questions and Answers Accommodation - ️️ The ability of the crystalline lens to adjust power to provide retinal focus of images of objects closer than optical infinity Aphakia - ️️ Absence of the crystalline lens. Astigmatism - ️️ A refractive defect where the refractive surface has different power in different meridians As a result the image formed of a point object will not be a point but a line Axis (cylinder) - ️️ The weakest or least curved meridian on the surface of a cylindrical or toric surface Axis (principal) - ️️ An imaginary line going through the geometric center of an optical system perpendicular to the surface. Base Curve - ️️ Of a contact lens the curvature of the posterior optical portion otherwise known as the Posterior Central Curve Cylinder - ️️ An object whose surface is curved differently in different meridians with the axis having zero curvature Cylinder Lens - ️️ A lens with different power in different meridians due to one or more surfaces having cylindrical or toric shape Cylinder Power - ️️ The algebraic difference in power between the principal meridians of a cylinder lens Diopter - ️️ A unit of measurement equal to the reciprocal meter used to measure vergence of light and power of optical len