Black spot in my vision!!

Hello,
I am hoping someone out there can help me with my eye problem.  I am a 33 y/o male with no history of eye problems until last year when I started to see a small transparent black spot in my left eye.  It is in the same place at all time(seem like the lower left side). It is strong when I am outside either in the sun or a bright white background such as clouds and or snow, even my computer background.  I rearly see it indoors where it is not as bright.  I can focus on it but not for a long time.  It feels like it is in my perpherial vision.  I went to an optomologist in the sense that it was a floater and after a full eye exam and him checking for floaters, he found nothing.  He took an image of my macula and stated that it was fine.  He must of spent almost an hour checking my eye out.  His answer was I see no floaters or anything. My eye was dilated at that time and at the moment i was unable to see the black spot when I drove home or looked out the window.  I started to see it the next day when I looked out at the snow.  It also feels sometimes like my eye has a slight flash to it when I look left to right.  does anyone have any info on what it could possible be or what i should have my optomologist check.  Could it be my retina?  
I am so lost and confused on what it is.

[John C Hagan III, MD, FACS, FAAO]

Some floaters are too small for the eye md to see but you can see. I would suggest a second opinion with a retina Eye MD ophthalmologist.  Find one near you at www.aao.org

JCHMD