Can you add a recessed ceiling light? they have them for "wet" locations.

You can install a can light that is made for wet locations, such as

http://www.lightinguniverse.com/recessed-can-lights/thomas-lighting-ps1nsp-6in-air-seal-housing-recessed-can-light-8-pack_g206636.html?isku=1762734&linkloc=searchProductItemsImage

.... just make sure you buy a trim kit as well

Since you have 5x7 shower, you should be able to get two in there to really brighten things up! I would have an electrician do an estimate for you to make sure you have adequate wiring to do this, and if not... what it would take. Hope this helps :)

How about a skylight? Natural light flooding your shower could be wonderful.

ok thanks for the input....we already have a 'wet potlight" i was looking for more natural light..it is on the main floor with a second story above so a skylite is out. I am concerned about water penetration and mould so I want an interior wall solution and I am having trouble so hence the need for input. Thanks

Could you post a picture so that we can understand the issue better and direct our comment accordingly.

You could try adding more glass if the shower isn't cased on 3 sides. Photos or a plan would be helpful.