# (physics) Calculating eye diameter

• rickymhoff
In summary, it is possible to calculate the diameter of the eye from front to back based on the type of glasses a person needs. This can be done by determining the closest point at which the person can see sharply. The diameter of the eye is typically measured as 9.2mm and the focal length of the lens as 16.67mm.
rickymhoff
Is it possible to calculate the diameter of the eye from front to back when you what kind of glasses the person needs? Like if someone needs -2 type of glasses is it possible to calculate the eye diameter?

If not would it be possible to determine someones eye diameter by determine the closest point at which the person can see sharp?

This is what someone gave me to help but i don't know if its useful? I can't contact that person right now.

The diameter of the eye is roughly equal to the focal length of the lens times the refractive index of the goo( can't spell aqueus humor ) inside your eye.

Generally the radius of the eye is taken as 9.2mm and the focal length of the lens 16.67mm - look for "Indiana Reduced Eye Model"

I can say that it is not possible to calculate the diameter of the eye from front to back based on the prescription for glasses. The prescription for glasses is determined by the refractive power of the eye, which is affected by multiple factors such as the shape and size of the cornea, the length of the eye, and the curvature of the lens. The prescription does not directly correspond to the physical diameter of the eye.

However, it is possible to estimate the eye diameter by determining the closest point at which a person can see sharp. This is known as the near point of accommodation and is typically measured during an eye exam. The near point of accommodation is affected by the size and shape of the eye, so it can provide a rough estimate of the eye diameter.

It is important to note that the eye diameter can vary among individuals and can also change with age. Therefore, the near point of accommodation may not always be an accurate measure of the eye diameter. Other methods, such as using specialized imaging techniques, may be needed for a more precise measurement.

I hope this helps answer your question. If you have further inquiries, I suggest consulting with an optometrist or ophthalmologist for more specific information about your individual eye measurements.

## What is the purpose of calculating eye diameter?

The purpose of calculating eye diameter is to determine the size of the eye, which can be used for various purposes such as designing eyeglasses or contact lenses, understanding the optics of the eye, and studying visual perception.

## What are the factors that affect eye diameter?

The factors that affect eye diameter include genetics, age, sex, race, and health conditions such as myopia or hyperopia. Environmental factors such as lighting and visual demands can also have an impact.

## How is eye diameter measured?

Eye diameter is typically measured using a caliper or ruler to determine the distance between the corneal surfaces. It can also be estimated using imaging techniques such as ultrasound, MRI, or optical coherence tomography.

## What is the average eye diameter for humans?

The average eye diameter for humans is around 24 mm, but it can vary depending on individual characteristics. For example, newborns typically have smaller eyes, while adults with certain health conditions may have larger eyes.

## How does eye diameter affect vision?

The eye diameter plays a role in vision by influencing the shape and size of the eye's optical elements, such as the cornea and lens. This can impact the focusing ability of the eye and may contribute to visual impairments such as nearsightedness or farsightedness.

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