Can anyone tell me what my glasses prescription means?

I went to the optician today and I need to get some glasses. I have some basic knowledge about ophthalmology as I'm about to be a doctor, so I know the basics about how light focuses on the eye etc etc. And I understand the basic concept of astigmatism and how the eye is shaped more lke a rugby ball than a football....

Anyway, my prescription from the optician is:

R: SPH -1.00 CYL -0.50 Axis 115
L: SPH -1.25 CYL - 0.50 Axis 90

I understand that it shows myopia in both eyes, left slightly worse than right, but what do the other numbers mean? It's something to do with the degree of astigmatism, but what do they actually show? And what does that mean in terms of my eyes?

Just interested!!!

SPH means sphere, CYL means cylinder. Just some instructions about how should the optician cut your glass.

I wish i could help! All i know is that i am a lot blinder than u, im -6.25 in both eyes! :-(