Question time-Blurring vision

If we look at the spark that comes while welding, our vision gets blurred why?

The explanation can be given in two ways.

(2) The other simple explanation is, the temporary lapse in recognizing the intensity difference between the bright and the dull area of the seen viewed, due to incomparable higher intensity light (spark) from the brighter area. The picture or seen is recognized in the brain by a matrix form built by (a) the difference in light intensities over different areas and (b) the difference in the frequencies of light (colour). The matrix get troubled on receiving the brighter light. This is why we experience a blurred vision.

Dr. S.A. Saadhali, Aruppukkotttai, Tamil Nadu

(Ref:http://www.thehindu.com/sci-tech/question-corner-blurring-vision/article8921841.ece)