The average human retina has five million cone receptors which are responsible for color vision and a hundred million rods that detect monochrome contrast, which plays an important role in the sharpness of the image seen by the eyes.
Most digital cameras have orthogonal pixels which means each pixel is set out in a regular grid pattern, with a filter called the 'Bayer' filter which delivers red, green and blue pixels. On the retina, there is a small central area, (the macula), that contains the densest concentration of photo receptors in the eye.
The macula contains about 150,000 pixels in each 1 mm square and provides 'central vision'. The rest of the retina has fewer pixels, most of which are black and white sensing only. It provides the 'peripheral vision', that is, the things we see in the corner of our eye. The brain processes these signals a lot more differently than a camera.
If we take 120 degrees as the horizontal field of view and 60 degrees in the vertical plane, a pixel size of 0.3 arc-minutes will translate to 576 megapixels of available image data. This means that if the human eye was a camera, it would cost approximately $35,268,800 + Tax!