Contact lenses, focal length and uncorrected far point distance

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SUMMARY

The discussion centers on calculating the uncorrected far point distance for a nearsighted individual using contact lenses with a focal length of -7.6 cm and a far point distance of 8.7 m with glasses. The formula 1/F = 1/do + 1/di is applied, where F represents focal length, do is object distance, and di is image distance. The calculations reveal that the uncorrected far point distance is approximately -7.534 m. Participants emphasize the importance of understanding the relationship between the eye's lens and the corrective lenses used.

PREREQUISITES
  • Understanding of optics, specifically lens formulas
  • Familiarity with the concepts of focal length and image distance
  • Basic knowledge of nearsightedness and corrective lenses
  • Ability to manipulate algebraic equations
NEXT STEPS
  • Study the lens formula in detail, particularly 1/F = 1/do + 1/di
  • Research the anatomy of the eye, focusing on the role of the lens
  • Explore the effects of different focal lengths on vision correction
  • Learn about the physics of light and how it interacts with lenses
USEFUL FOR

Optometrists, physics students, and anyone interested in understanding the principles of vision correction and the optics of lenses.

danok
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1. A nearsighted person wears contacts with a focal length of -7.6cm. If this person's far point distance with her glasses is 8.7m, what is her uncorrected far point distance?



2. 1/F=1/do+1/di



3. 1/-7.6=1/do+1/870
=-7.534


I am completely lost here...please help. Thanks!
 
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So it's not just me then...
 


The image distance is constant in both cases (the length of the eyeball)
You have an unknown focal length lens (the eye) and a combintion of the same unknown lens and a known lens with a known object distance.

So write the equations for object, image distance and focal length for both cases.
 

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