The use of subindices with greek letters

I need to use subindices with greek letters. But I find that the result is sometimes decipherable.

Examples:

$\alpha_{H}$, $\gamma_{H}$


Do you have any suggestion in that regard? Of course, I do not want to use another subindex than "H".

-

\def\H{\rule{0pt}{1.5ex}H}
$\alpha_H \gamma_H$ $\alpha_{\H} \gamma_{\H}$

Or just an empty supercript $\alpha^{}_{H}$ often helps –  Danie Els May 18 '11 at 7:24