Thank you for the additional information.
There are a couple things that come to mind when I hear of an Akita with gradual vision loss. There are other possibilities as well but I will focus on a couple common ones.
1. Vogt-Koyanagi-Harada-Like Syndrome in Dogs
The other name for this disease is uveodermatologic syndrome. The reason this may be a cause is because of her breed. It is common in Akita's and can lead to blindness. Also, you mentioned the eyes look cloudy, but without cataracts. If the cornea is cloudy this could indicate inflammation called uveitis. The things that don't quite fit that you have mentioned is that she is not painful and her eyes are dilated. UsuallIy with uveitis (inflammation within the eye), the eyes are painful, bloodshot and the pupils are usually constricted, not large and dilated. There are medications used to control the inflammation. Also, dogs with this disease will have fur turn white around the face.
2. Progressive retinal atrophy (PRA). This also has a hereditary component and Akita's are one of the breeds that are more likely to develop it. It is a problem that causes gradual vision loss over a period of months to years. The back of the eye (the retina) has light receptors (photoreceptors). For some reason, in some dogs, these photoreceptors develop normally but start to deteriorate/degenerate later in life. Common things owners notice is decreased night vision, hesitancy to do stairs. Then, eventually vision during the day is decreased. The pupils can be dilated, and you may see the reflection in the back of the eye more easily (it looks like a yellow or green shimmer). There is no treatment for PRA, except for keeping your dog in a safe environment. You can get some ideas here: www.ehow.com/how_7562_live-with-blind.html
An opthalmologist would be able to give you a diagnosis for what is causing your dog's vision loss. If you let me know your city/state, I could find one for you. You could call them ahead of time to see what the exam fee is and what it includes. They may know just with an exam. There are other diagnostic tools that may be recommended, but they wouldn't know that until your visit. If you are able to, a visit to the specialist will be able to determine the cause of the problem and if there is anything you can do to treat it or at least slow the progression.
I hope my answer was helpful. Please let me know if you have other questions. I am here to help!