Eye/Lens Question: How Many Diopters of Adjustment Does an Adult Eye Have?

  • Thread starter Thread starter dranger35
  • Start date Start date
AI Thread Summary
An adult eye typically has a diopter adjustment range from about 58.8 to 65.5 diopters, allowing it to focus on objects from a distance of 17 mm to as close as 15 cm. The focal length of the eye's lens adjusts based on the distance of the object being viewed. Some users shared personal experiences, noting their specific diopter ranges based on age and vision correction needs. For example, one individual reported a range of 2 diopters due to age-related changes in vision. Overall, the discussion highlights the variability in diopter adjustment among adults, influenced by individual factors.
dranger35
Messages
14
Reaction score
0
I have a question concerning the eye but I need to know how many diopters of adjustment an adult eye has? I've been looking online a lot but can't find what the answer is. Please help.
 
Physics news on Phys.org
dranger35 said:
I have a question concerning the eye but I need to know how many diopters of adjustment an adult eye has? I've been looking online a lot but can't find what the answer is. Please help.
The eye has to focus the image on the retina which is located about 17 mm behind the lens of the eye. The focal length of the lens of the eye adjusts to the range of the object being viewed. To view an object at a long distance away, the lens must have a focal length:

\frac{1}{f} = \frac{1}{o} + \frac{1}{i} = 0 + \frac{1}{i} so

f = i = 17mm

A lens with a focal length of 17mm, has a diopter value of 1/.017 = 58.8

If the eye can also focus on an object up to a distance of 15 cm (6 inches), then:

\frac{1}{f} = \frac{1}{.15} + \frac{1}{.017} = 65.5

So the diopter range of the eye is from about 58.8 to 65.5 diopters.

AM
 
Last edited:
dranger35 said:
I have a question concerning the eye but I need to know how many diopters of adjustment an adult eye has? I've been looking online a lot but can't find what the answer is. Please help.
It's an easy thing to measure. Can you focus to infinity? And as close as 1 foot (.3 m)? Then your range is 1/.3m - 1/infinity = 3.3 diopters.
I'm a totally different example: My closest focus without glasses for my right eye is 0.17m, farthest focus is 0.25m. So the range is 1/.17-1/.25= 2 diopters. (That's because I'm over 50.) And of course to correct my farthest focus to infinity requires a -6 diopter correction (6 diopters = 1/.17m). That's my prescription. When correected, my close focus is 1/2diopters = 0.5 metre.
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Contact Lenses Optics Problem (Two-Parts)
Replies
2
Views
4K
Thin Lens Equation: Nearsighted
Replies
1
Views
7K
Understanding Far Points and Lens Power in Correcting Myopia
Replies
2
Views
2K
Calculating Diopters for Bifocals: What Power Should They Have?
Replies
2
Views
2K
Imaging resolution for a microscope and eye
Replies
5
Views
2K
Calculating Lens Power: Q&A for Diopters
Replies
1
Views
2K
B Question about the relative motion of an eye relative to light source
Replies
3
Views
995
I Understanding magnification of concave mirrors for near-eye situation?
Replies
11
Views
2K
Lens Maker's Formula - Confusion in the derivation
Replies
15
Views
1K
B Does light ever go from the eye to the image?
Replies
17
Views
3K

Hot Threads

Recent Insights

Back
Top