In my chosen profession the numerical expression shown below is an example of what I deal with on a regular basis through my working day.
R +0.25/+1.25 x 165
L +0.25/+0.75 x 20
Add +1.50 R&L
These particular figures could also be represented thus:
R +1.50/-1.25 x 75
L +1.00/-0.75 x 110
Add +1.50 R&L
The first version of the example is what we call the plus-cylinder form, the second version is the minus-cylinder form. They both amount to the same thing. Converting from one form to the other is referred to as transposition.
OK, so that's the illustration out of the way. Here are the actual figures I'm giving you to work with, followed by some questions to answer which will allow you to work out the co-ordinates for this cache.
R +3.00/+1.00 x 5
L +1.00/+2.00 x 150
Add +2.00 R&L
The cache is located at: N 51° 30.ABC E 000° 26.DEF
A = amount of astigmatism in left eye + 2
B = the plus-cylinder axis for the right eye + 3
C = mean sphere (a.k.a. spherical equivalent) for left eye + 7
D = amount of extra lens power included to help with near tasks - 2
E = the minus-cylinder axis for left eye divided by 10
F = standard distance (metres) for eye testing - 3
You can check your answers for this puzzle on GeoChecker.com.