Calculating properties of eyes

[Wai]

I'm asking these questions because I've honestly never done them in class, the teacher was absent today, and I haven't been able to find the solution in the textbook:

 

An eye of mean diamter 2.5 cm has a near point of 15 cm and far point of 120 m.

1. When this eye looks at an object placed at its far point, what will it's focal length be?

2. When an object is 1 cm from the eye, what is the power of the eye's focusing system in dioptres?

 

I've done all the other questions that I was given, and this is due tomorrow.

 

Once again, thanks for guiding us students.

[Genecks]

You could always do independent research by visiting a local eye-exam place. Call an optometrist and start asking questions. You might get a better understanding of vision that way. Eyes are a fascinating topic, but I've never researched them into this much depth. Typically, it's not that required to understand vision that much, unless someone is in a medical field.

[John Cuthber]

Have you studied lenses and image formation in general? The fact that this lens is in an eye is a bit of a distraction. (In fact, a more accurate idea of how the eye works means that there isn't enough information to answer the question so they must be expecting a fairly simple model.)