Reading Lens for Windows Phone 8 is a simple app that will help you read small text, much like a pair of reading glasses would. The app makes use of the Windows Phone camera to magnify small print so it can be easily read.
Even if you aren't needing to go get your eyes checked, Reading Lens will help you read the tiny print on medicine bottles, coupon expiration dates, contracts and other documents where fine print is prominent.
If the normal magnification isn't enough, you can pinch the screen to zoom. There are also control to turn on your Windows Phone LED light and to pause the image for better reading. You could use your camera app to do the same thing but you have the hassle of pressing the shutter button down to focus in on things and you lack the ability to turn on the camera light to use as a reading lamp.
Reading Lens is free for a limited time only (not sure what regular pricing will be) and you can find Reading Lens here at the Windows Phone Store.