0
What type of lens is used in spectacles to correct long sightedness?
Wiki User
∙ 11y ago
Convex lenses, which magnify, correct hyperopia. Below, is a previous wiki answer to this question in detail.
Convex are thicker in the middle and thin out at the edges. These lenses magnify and are used for reading glasses and to correct long-sightedness (hyperopia).
Concave lenses are thin in the middle and thick towards the edges. These lenses shrink things and are used to correct short-sightedness (myopia).
A good example of this is to take a spoon and look at your reflection in it. Looking at the concave side of the spoon (the front) will make you look smaller, looking at the convex side of the spoon (the back) will make you look bigge
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
What do the ciliary muscles on the lens do when they see focus on something far away?
They pull the lens to make it long and thin.
Is A meteor is a piece of an asteroid that exploded long ago A correct sentence?
Yes yes it is
How long does it take for the moon to do one orbit around earth?
If I am correct approximately one month.
How long does it take the moon to change from new moon to a first quarter?
im guessing one week please correct me if im wrong
How long did it take to prepare for the Apollo 13 mission?
i think it was like 5 days 22 hours and 54 min. If im wrong you can correct me...
What do the lens do in the eye to help us see?
the lenses make objects look smaller than what they are so that people know what they look like.
How do glasses solve the problem of short and long sightedness?
Short and long sightedness are caused by the lens of the eye focusing the light either in front of or behind the retina. Glasses alter the path of light going into the lens to adjust for this.
Is 2 diopters a positive power?
If it is written as +2 Diopters it is positive, ie a converging lens. If it is written as -2 Diopters it is negative, ie a diverging lens. Diverging lenses are prescribed for myopia, or short-sightedness. Converging lenses are prescribed for hypermetropia or long-sightedness.
What lens used to correct nearsightedness?
Convex lenses are thicker in the middle then the edges and concave are thicker at the edges then the middle. When light travels through lenses, refraction occurs. The light bends either outward or inward, it depends on the lens.The lens of your eye is a double convex lens. Its job is to focus the image on the retina of the eye. If one is farsighted, the lens in the eye causes the focus to be behind the retina. These people see far but have some difficultly seeing close-up.To correct this farsightedness, the person would wear glasses or contacts with convex lenses, for It is often used for close examination of small objects.
Can cadets having spectacles join the infantry of an army?
As long as the spectacles correct his vision to normal range then it should not prevent military participation.
Why do some people have difficulty seeing properly?
Because the lens (translucent layer of membrane over the iris) is either too thick, or too thin, causing light to be reflected at the wrong angle. There are two kinds of vision impairment: Long Sightedness Short Sightedness
Why do some people wear spectacles?
People wear spectacles to correct visual conditions such as hyperopia, myopia and presbyopia. Hyperopia (also known as long sightedness) is a condition where the eye cannot focus on near objects and in some cases the eye won't be able to focus properly on objects at any distance. A positive lens which is convex in shape (+ powered prescription) will be used for this condition. Myopia (also known as short sightedness) is the opposite. A myopic eye won't be able to focus on far away objects but a myopic eye can usually to focus on close up objects with ease. A minus lens which is concave in shape (- powered prescription) will be used to correct this condition. Prebyopia is a condition where the crystalline lens which is inside the eye becomes less flexible with age and loses the ability to focus on near objects. This condition is common for people over the age of 40 years. There are also other more complex reasons for people to wear corrective prescription lenses but these are the main reasons. Or sometimes you don't need them when ur young but ur eyes change as you get older so u may need them when ur older.
Should a short sighted person use a concave or convex lens?
This is a lens which is designed to help someone who has problems seeing at distance (myope), the light rays going into your eye are not hitting the fovea (the part of the eye located on the retina which allow you to see clearly) in the proper place, these rays are falling in front of the fovea, so by using a concave ( a minus lens) lens, this moves these light rays by diverging them and moving them back to the fovea which allows for clear vision at distance. At least this is how a concave lens is used optically speaking.this is from winter006: concave mirrors are used in stores and gas stations to see a wider area of the store.It's also called , a Diverging Lens .It is thinnest in the centre and spreads light out , so it gives a diminished image .
Which type of lens is present to correct the defect of long sightdness?
Farsightedness is corrected using a concave type lens.
How does the eye respond to light rays to manifest long sightedness?
how does the eye respond to light rays to manifest far sightedness
What causes short sight and how it can be fixed?
Myopia, or near-sightedness, is caused because the eyeball is too long in relation to the focusing power of the lens onto the retina. This causes the image to be focused at a point in front of the retina rather than on top of it. There are two ways to correct this: corrective lenses (eyeglasses or contact lenses) or surgery.
Is concave lens is used to cure short sightedness?
converging property of concave lens. In myopia or short sight, light rays come to a focus in front of retina . Concave lens diverges light rays before they fall on the cornea; then they are converged by cornea and then by human lens to come to a focus on the retina. Now the image is seen clearly which was blurred / out of focus when seen without glasses.
