You probably have too-small a screen or too small letters on your screen, though for what it's worth there really i no ergonomic way to use a laptop that doesn't involve at least one of an external keyboard or screen. Increase your font sizes, and you may not feel the need to lean in so much. (And/or see an eye doc.)

And working at home (or in a startup you run, I guess) means you can do things to help your health and productivity even if they might seem ridiculous, like take naps and walk while you type. Yet another reason I don't see myself ever having a 'normal' job again. (And most people seem to think my treadmill desk is pretty cool, fwiw.)