For those who do not wish to use a magnifying glass, there are a few alternatives to reading aids for people with low vision that are available.

We have just discussed the basic and important concepts associated with spherical mirrors. Let's now talk about how they're used.

Below, we’ve outlined what magnifying glasses are, why they are often used, and when to consider utilizing a magnifying glass to improve your vision and quality of life.

100xMagnifying Glass

Start by tracing a line from the center of curvature of the sphere through the geometric center of the spherical cap. Extend it to infinity in both directions. This imaginary line is called the principal axis or optical axis of the mirror. Any line through the center of curvature of a sphere is an axis of symmetry for the sphere, but only one of these is a line of symmetry for the spherical cap. The adjective "principal" is used because its the most important of all possible axes. Compare this with the principal of a school, who is in essence the most important or principal teacher. The point where the principal axis pierces the mirror is called the pole of the mirror. Compare this with the poles of the Earth, the place where the imaginary axis of rotation pierces the literal surface of the spherical Earth.

Depending on the task the magnifier is needed for, single-lens magnifiers are often a satisfactory option for activities like reading. Higher power magnifiers are available, and they usually consist of two or more lens elements that result in an improved resolution.

BestMagnifying Glassfor Seniors

Rays of light parallel to the principal axis of a concave mirror will appear to converge on a point in front of the mirror somewhere between the mirror's pole and its center of curvature. That makes this a converging mirror and the point where the rays converge is called the focal point or focus. Focus was originally a Latin word meaning hearth or fireplace — poetically, the place in a house where the people converge or, analagously, the place in an optical system where the rays converge. With a little bit of geometry (and a lot of simplification) it's possible to show that the focus lies approximately midway between the center and pole. I won't try this proof.

Positions in the space around a spherical mirror are described using the principal axis like the axis of a coordinate system. The pole serves as the origin. Locations in front of a spherical mirror (or a plane mirror, for that matter) are assigned positive coordinate values. Those behind, negative. The distance from the pole to the center of curvature is called (no surprise, I hope) the radius of curvature (r). The distance from the pole to the focal point is called the focal length (f). The focal length of a spherical mirror is then approximately half its radius of curvature.

Large print books are available that are easier to read than smaller print books. Audiobooks are also available for those who do not wish to read with a magnifying glass.

Magnifying glasses usually consist of a convex lens that bulges outward, which is normally made of glass or plastic. It is a lens that magnifies objects.

Locations in front of a diverging mirror have positive position values, since points in front of any mirror are always positive. The distance from the pole to the center of curvature is still the radius of curvature (r) but now its negative. The distance from the pole to the focus is still the focal length (f), but now it's also negative. With two sign switches, the rule that focal length is half the radius of curvature is still true in the same approximate way as before.

MagniPros also offers a hand-held magnifier, the 4x Large Magnifying Glass, which features a crystal-clear acrylic crystal made of optical grade, scratch-resistant materials. This is a good option for readers who are on the go. This option is around $25 on Amazon.

One of the easiest shapes to analyze is the spherical mirror. Typically such a mirror is not a complete sphere, but a spherical cap — a piece sliced from a larger imaginary sphere with a single cut. Although one could argue that this statement is quantifiably false, since ball bearings are complete spheres and they are shiny and plentiful. Nonetheless as far as optical instruments go, most spherical mirrors are spherical caps.

Now, imagine a mirror with the opposite curvature — one where the reflecting surface is on the "outside", like looking into a spoon that's been flipped upside down from its useful orientation, a convex mirror. Let's shine paraxial rays onto this mirror and see what happens.

Best Handheldmagnifying glass

Professionalmagnifying glass

Individuals who would like to avoid surgery might consider either glasses or a magnifying glass if only activities like reading have been compromised. Being able to see the small print of certain editions of books or menus becomes a marked challenge later in life. In these cases, a magnifying glass often helps.

Brightech manufactures a 2-in-1 magnifying glass that comes in a hands-free design and offers 25x magnification. This magnifying glass can act as a reading enhancement tool and a reading lamp simultaneously. The cost is just over $20 on Amazon.

Presbyopia can come along with symptoms that include having to hold reading materials farther away in order to read, increased eye strain, and headaches.

Convex mirrors are diverging mirrors. Instead of converging onto a point in front of the mirror, here rays of light parallel to the principal axis appear to diverge from a point behind the mirror. We'll also call this location the focal point or focus of the mirror even though its disagrees with the original concept of the focus as a place where things meet up. In your best Russian reversal voice say, "In convex house, people go away from hearth" (or something like that, but funnier).

The aging process often includes changes in overall eyesight and vision. Age-related farsightedness makes it difficult to see things up close. For many individuals who enjoy reading, glasses or magnifiers become necessary in order to curl up with a nice book.

MyVision.org is an effort by a group of expert ophthalmologists and optometrists to provide trusted information on eye health and vision.

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Age-related farsightedness can start to set in when a person reaches their 40s. Also called presbyopia, this gradual, age-related loss of ability to focus on nearby objects can become a more serious issue over time. In many cases, individuals are no longer able to keep up with their normal reading schedule out of difficulty or frustration.

Imagine a set of rays parallel to the principal axis incident on a spherical mirror (paraxial rays as they are sometimes called). Let's start with a mirror curved like the one shown below — one where the reflecting surface is on the "inside", like looking into a spoon held correctly for eating, a concave mirror.

MagniPros offers their Hands-Free Magnifying Glass Large Full-Page Rectangular 3X Magnifier LED Lighted Illuminated, which features a dozen LED lights for enhanced reading. This model features a large surface area for viewing and reading larger books or magnifying entire pages. This model is priced at just shy of $32 on Amazon.

Curved mirrors come in two basic types: those that converge parallel incident rays of light and those that diverge parallel incident rays of light.

High quality magnifying glassfor reading

If you’re wondering what the best magnifier is for you, it’s best to consider what you will be using your magnifier for. If you’re thinking of nighttime reading, you might want a hands-free magnifier, for instance.

Reading glasses or contact lenses can be prescribed to fit your individual needs. LASIK surgery is another option that has been shown to improve vision for those who undergo treatment.

Note: This page should not serve as a substitute for professional medical advice from a doctor or specialist. Please review our about page for more information.

It is important to note up front that this is an approximately true relationship. We will assume it to be exactly true until becomes a problem. For many mundane applications, it's close enough to the truth that we won't care. It's not until we encounter situations requiring extreme precision that we'll deal with this aberration (as it is literally called). Astronomical telescopes should not be built with spherical mirrors. Real telescopes are made with parabolic or hyperbolic mirrors, but as I said earlier, we'll deal with this later.