A report on Glasses

$A skyline seen through a corrective lens, showing the effect of refraction$

Doubleframe eyewear with one set of lenses on the moving frame and another pair of lenses on a fixed frame (optional).

Glasses, c. 1920s, with springy cable temples

Modern glasses with a rectangular lens shape

Detail of a portrait of the Dominican Cardinal and renowned biblical scholar Hugh of Saint-Cher painted by Tommaso da Modena in 1352

Portrait of cardinal Fernando Niño de Guevara by El Greco circa 1600 shows glasses with temples passing over and beyond the ears

The Glasses Apostle by Conrad von Soest (1403)

Seated apostle holding lenses in position for reading. Detail from Death of the Virgin, by the Master of Heiligenkreuz, c. 1400–1430 (Getty Center).

French Empire gilt scissors glasses (with one lens missing), c. 1805

A portrait of Francisco de Quevedo y Villegas, 1580–1645

Harry S. Truman, 33rd President of the United States, had poor vision.

Woman wearing eyewear with non-prescription lenses in a fashion photo shoot.

Glasses - Decoration, Presi HQ, Budapest

Glasses, also known as eyeglasses or spectacles, are vision eyewear, with lenses (clear or tinted) mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms (known as temples or temple pieces) that rest over the ears.

- Glasses

50 related topics with Alpha

Diagram showing changes in the eye with near-sightedness

Myopia

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Eye disorder where light focuses in front of, instead of on, the retina.

Glasses are commonly used to address near-sightedness.

Compensating for myopia using a corrective lens.

Estimated myopia rate in 20-year-olds in Asia.

Myopia rate in Europe by birth decade (1910 to 1970).

Near-sightedness can be corrected with eyeglasses, contact lenses, or a refractive surgery.

Presbyopia

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Physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects.

Presbyopia can be corrected using glasses, contact lenses, multifocal intraocular lenses, or LASIK (presbyLASIK) surgery.

Far-sightedness

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Condition of the eye where distant objects are seen clearly but near objects appear blurred.

Far-sighted vision on left, normal vision on right

Choroid folds in high hyperopia (fluorescein angiography)

Management can occur with eyeglasses, contact lenses, or refractive corneal surgeries.

Contact lens

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Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes.

One-day disposable contact lenses with blue handling tint in blister-pack packaging

$Artist's impression of da Vinci's method for neutralizing the refractive power of the cornea$

In 1888, Adolf Gaston Eugen Fick was the first to successfully fit contact lenses, which were made from blown glass

Otto Wichterle (pictured) and Drahoslav Lím introduced modern soft hydrogel lenses in 1959.

Woman wearing a cosmetic type of contact lens; enlarged detail shows the grain produced during the manufacturing process. Curving of the lines of printed dots suggests these lenses were manufactured by printing onto a flat sheet then shaping it.

Scleral lens, with visible outer edge resting on the sclera of a patient with severe dry eye syndrome

Contact lenses, other than the cosmetic variety, become almost invisible once inserted in the eye. Most corrective contact lenses come with a light "handling tint" that renders the lens slightly more visible on the eye. Soft contact lenses extend beyond the cornea, their rim sometimes visible against the sclera.

Molecular structure of silicone hydrogel used in flexible, oxygen-permeable contact lenses.

Young woman removing contact lenses from her eyes in front of a mirror

Contact lenses soaking in a hydrogen peroxide-based solution. The case is part of a "one-step" system and includes a catalytic disc at the base to neutralise the peroxide over time.

CLARE (contact lens associated red eye) is a group of inflammatory complications from lens wear

Christopher Lee as the title character in Dracula (1958) in one of the first uses of contact lens with makeup in films

Aesthetics and cosmetics are main motivating factors for people who want to avoid wearing glasses or to change the appearance or color of their eyes.

These bifocals are upside down as they rest on the surface. The add segment of the lens for near vision is the "D" shaped area.

Corrective lens

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Lens that is typically worn in front of the eye to improve daily vision.

Chromatic aberration caused by a convex lens

Prismatic color distortion shown with a camera set for nearsighted focus, and using -9.5 diopter eyeglasses to correct the camera's myopia.

Close-up of color shifting through corner of eyeglasses. The light and dark borders visible between color swatches do not exist.

Crude relationship between lens size and its thickness for the same radius of curvature. Notice that in addition to its smaller surface area, the small lens is also much thinner and so is much lighter.

The effects of an anti-reflective coating applied (as seen on the bottom picture) as compared to regular eyeglass lens (notice how the reflection of the photographer in the top lens is clearly visible)

Glasses or "spectacles" are worn on the face a short distance in front of the eye.

Lens

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Transmissive optical device which focuses or disperses a light beam by means of refraction.

$Light being refracted by a spherical glass container full of water. Roger Bacon, 13th century$

Lens for LSST, a planned sky surveying telescope

The position of the focus of a spherical lens depends on the radii of curvature of the two facets.

A camera lens forms a real image of a distant object.

Virtual image formation using a positive lens as a magnifying glass.

Images of black letters in a thin convex lens of focal length f are shown in red. Selected rays are shown for letters E, I and K in blue, green and orange, respectively. Note that E (at 2f) has an equal-size, real and inverted image; I (at f) has its image at infinity; and K (at f/2) has a double-size, virtual and upright image.

They are also used as visual aids in glasses to correct defects of vision such as myopia and hypermetropia.

Blur from astigmatic lens at different distances

Astigmatism

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Type of refractive error due to rotational asymmetry in the eye's refractive power.

Three treatment options are available: glasses, contact lenses, and surgery.

$A correctly-focused eye (top), and two showing refractive error: in the middle image, the light is focused too far forward; in the bottom image, the focal point is behind the eye$

Refractive error

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Problem with focusing light accurately on the retina due to the shape of the eye and or cornea.

$A correctly-focused eye (top), and two showing refractive error: in the middle image, the light is focused too far forward; in the bottom image, the focal point is behind the eye$

Top: farsighted corrected using convex lens Bottom: nearsighted corrected using concave lens.

Fundus of person with retinitis pigmentosa, early stage

$A doctor uses a trial frame and trial lenses to measure the person's refractive error.$

$DALYs per 100,000 people due to refractive errors in 2004. No data Less than 100 100-170 170-240 240-310 310-380 380-450 450-520 520-590 590-660 660-730 730-800 More than 800$

Refractive errors are corrected with eyeglasses, contact lenses, or surgery.

Progressive lens

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Progressive lenses, also called multifocal lenses, progressive addition lenses (PAL), varifocal lenses, progressive power lenses, graduated prescription lenses, or progressive spectacle lenses are corrective lenses used in eyeglasses to correct presbyopia and other disorders of accommodation.

A bifocal lens with areas of differing magnification

Bifocals

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Bifocals with separate lenses. In this case, the Swedish ethnologist Jan-Öjvind Swahn.

Bifocals are eyeglasses with two distinct optical powers.