Magnifiers are important tools in the armamentarium of optometrists working to improve visual performance. However, outside the hospital setting their use is frequently overlooked. Apprehension of their optics is undoubtedly a discouraging factor for some clinicians. This article explains the importance of these aids and guides the uninitiated through the implications of basic formulae associated with plus-lens magnifiers. It is hoped that it will provide clinicians with the motivation and theory needed to begin prescribing these devices.