Field of View and Numerical Aperture - Dutton Institute - what is field of view microscope
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Anti-reflective coating has been a great development in eyeglasses, but it certainly doesn't feel that way when it gets scratched. The reflection may be gone, but the scratch is all that you can see. Luckily, there is a quick fix that you can perform with easily-found household items. Vinegar and mustard work together to fix scratches in the coating. Be warned: it may not work on the most stubborn of scratches, but it is certainly worth a try.