object disappeared

This is my first post.
I am working on tutorial “Introduction to character animation”.
I have successfully completed the tutorial upto modelling and applying metarials and textures to main body.
The next part is applying material and texture to eyes.
But to my surprise the eyes appear to have vanished. I am sure I have not deleted them.
A strange thing was noticed during last few steps — sometimes the eyes disappeared but after few steps they appeared again.
I thought it proper to ask the more experienced users the probable reason and if there is any way to recover the eyes.
If there is no way the eyes can be recovered I will create them again.

What you may be doing is instead of hitting g to grab the object (or in the process of doing something else), you’re mistakenly hitting h (i do this all the time…ALL THE TIME). To get them back hit alt+h and everything that you’ve hidden will be revealed

Things are also hidden if you change layer (keys 0-9 across the top of the keyboard).

Layers are also shown/hidden by the “Layer” buttons:


thanks Housearrest and quorn for relpies.

I tried alt-h but did not get back “the eyes”.
I also tried all the layers but could not see the eyes.

But neverthless I came to know the common mistake (hitting h instead of g)

Thanks all