If you find the text in iOS 7 too small or having trouble reading them, you can adjust system settings to make them more readable.
One quick fix is to go to Settings > General > Accessibility and turn on the “Bold Text” option. After a restart, the text should be easier to read than before.
Another solution is to turn on Dynamic Type support and adjust to a larger text font. Go to Settings > General > Accessibility > Larger Type. Turn on “Larger Dynamic Type” and drag the slider to adjust the text size.
Dynamic Type is a new iOS 7 system feature. Apps that incorporate dynamic type will adjust the font size according to this setting. You can check out the changes from apps such as Reminder, Notes and reader in mobile Safari.