I'm not sure eyesight is needed to check for blade damage.
Close your eyes. Run your finger along the edge of the blade.
If you feel any roughness or "catching" as your finger drags, then you have a damaged blade.
SPI would tell you this as well, but slightly after the fact. SPI will also tell you when your blade is gettting worn, rather than damaged. Also slightly after the fact.
In my opinion, for your situation of adding a maintenance check, perform a visual check every day at setup, sight along the blade edge for anything less than a perfectly straight edge, run your finger to assure no damage to the blade edge.
Let your SPI tell you when the blade is worn, let your "maintenance" tell you about blade damage.
Not a perfect solution, but possibly sufficient for your needs.
'hege
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