The only way to do it is to change the display resolution. Select the System Preferences->Hardware->Displays item and set the resolution to something smaller. This will make all the icons and text larger. However, changing from the native resolution of your screen will make some things less crisp.
The only other option would be to try some of the Zoom options under System Preferences->Universal Access
You can also simply click the Command and Plus keys to temporarily increase the font size, OR double tap the trackpad to zoom in and see something that is too small to read or a small picture and then double tap again to return to original size.
I hope this is helpful to you. I find the small setting of the font my MacBook Air came with not compatible with my 56 year old eyes.