It seems you want to remove the oversaturated pixels from your image, one of the ways you can do this is by thresholding and masking your image:
You can use “Threshold” module to detect the high intensity pixels (you can find the pixel intensities by hovering over each pixel and in the bar at the bottom right of your window, you’ll see the intensity). For example, you can set the threshold to be between 0.8 to 1 to pick the higher intensity pixels.
You then can use this thresholded image to mask your image, you want to invert your mask, so your final image has all the other areas, except the clusters and high intensity areas.
Then by using “IdentifyPrimaryObjects” module you can detect the fibers. You may need to enhance some features of the image by using “EnhanceOrSupressFeatures” before detecting the objects.