Advice on Glass Blocks

[gsNagesh]

I have an internal staircase landing extended by 15 inches or so from the outer walls. The extended part is covered by single brick wall (as its the site boundary). For ventilation the extended sides on either side the walls we are planning for fixed windows. some people are suggesting to go for 7x7 glass blocks. Being exposed to outside are these glass blocks safe or should I go with grilled wooden frames with glass fixed? Kindly suggest.
-Ngs.