# Help with optics problem involving diopters

• Altagyam
In summary, the conversation discusses a nearsighted man who uses contact lenses with a refractive power of -3.60 diopters and needs a prescription for eyeglasses. The individual attempted to use the mirror equation to find the correct prescription, but encountered some difficulty. After realizing a mistake in their calculations, they arrived at the correct prescription of -3.92 diopters.
Altagyam

## Homework Statement

A nearsighted man uses his ideally prescribed contact lenses that have a refractive power of −3.60 diopters. He would like a prescription for eyeglasses. What is the correct eyeglasses prescription if he wears his eyeglasses a distance of 2.30 cm from his eyes?

## Homework Equations

I used the mirror equation. 1/f = 1/do + 1/di

## The Attempt at a Solution

I found a solution to be -3.32 and what I did was convert the refraction power to focus and then convert it to centimeters and added 2.3 and then did the inverse of that to obtain -3.32 and apparently that is wrong. I have used chegg and they show the same exact method I employed. I don't understand. Help!

If his contact lenses are "ideally prescribed" I take that to mean perfect vision at infinity. So does it matter what the refractive power of the contacts is?

rude man said:
If his contact lenses are "ideally prescribed" I take that to mean perfect vision at infinity. So does it matter what the refractive power of the contacts is?

Altagyam said:
OK, I misread the problem anyway ...

## 1. What is a diopter?

A diopter is a unit of measurement used to quantify the refractive power of a lens. It is equal to the reciprocal of the focal length of the lens in meters.

## 2. How do I convert diopters to focal length?

To convert diopters to focal length, simply take the reciprocal of the diopter value. For example, a lens with a diopter value of 2 would have a focal length of 1/2 meter.

## 3. How does the diopter value affect the strength of a lens?

The diopter value indicates the strength of a lens in terms of its refractive power. A higher diopter value means a stronger lens, which can correct for more severe vision problems.

## 4. Can diopters be used for both nearsighted and farsighted vision?

Yes, diopters can be used for both nearsighted (myopia) and farsighted (hyperopia) vision. However, the diopter values needed for each may be different.

## 5. How do I calculate the diopter value needed for my vision correction?

To calculate the diopter value needed for vision correction, you will need to consult with an eye doctor. They will perform a comprehensive eye exam to determine your exact lens prescription and the corresponding diopter value.

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