When you see a blank wall or premise, you must have found some types of clouds in your field of vision, these are called floaters and they are tiny clumps of cells inside the vitreous that fills the inside of the eye.
Also, when the vitreous gel pulls on the retina, you will see lightening flashes in your eyes. As you grow older, these eye floaters and flashes will likely occur in your vision and it is alarming. You should always consult an eye specialist if they often occur.
Another eye disorder is macular degeneration and it is bit serious and you should not neglect it. Macular degeneration symptoms are sudden loss of the centre of the vision, change in perception of the color and many more.
Always hire a right doctor and start getting treatments for macular degeneration as it is something dangerous to neglect.
If you are looking for more information on the matter, you can visit http://www.retinadoctor.com.au/