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Magnifier Information
What Is A Fresnel Lens? A Fresnel lens for purposes
consists of a flat plastic lens with concentric grooves on one surface and a flat surface on the other side. Originally invented by Augustine Fresnel. The original Fresnel lenses were used
to magnify the lighthouse beacon light. A Fresnel lens is thinner and lighted then a ordinary convex magnifier lens.Wikipedia After the age of about
forty you will experience a problem viewing small print and tasks involving close detail work. This eye condition
is called presbyopia and a page size magnifier can help. Magnifier glass power
and work distance: Select a magnifier with a power that will allow you
to perform your task at a comfortable distance. The high power magnifier may not be the best magnifier for you. Our large magnifier selection can help those with presbyopia and macular degeneration Field Of View: The size of the area being magnified when viewing through a magnifier lens. The higher the power
of the magnifier the smaller the field of view.
Diopter: Diopter is a measurement that is used to calculate the power of a magnifier
lens. The higher diopter will provide higher magnification. Diopter is expressed as "D"
Power: Power is how large an object or print increases as you look through a lens. Magnifier power
is expressed as "X" Focal Length: Measurement from the center of the lens to to the object and be in focus . Focal Range: The distance
from the magnifier lens to the object
being viewed. Fresnel Magnifier : A flat magnifier consisting of concentric circles. Visual impairment (or vision impairment) is a decreased ability to see to a degree that causes problems
not fixable by usual means, such as glasses or medication. Our low vision magnifiers can be of help. Rules Of Magnification. - The higher the power
of the lens, the closer you must get to the object being viewed and the smaller the field of view.
- As the power of a lens
increases the diameter of the lens decreases.
- Diopter is a term used to determine the power(magnification}of a lens. The terms are
sometimes confused.
Informative
links: Craft Links Knitting, Crochet, and other Needlecrafts How To Sew Basic Sewing Stitches How to Crosstitch How To Do Needlework Reading
Links The National Federation of the Blind National Library Service for the Blind and Physically Handicapped Classroom National Eye Institute Optometry Cares American Action Fund for Blind Children & Adults MD Support National Eye Health Education Program | 
