You can try https://michaelbach.de/ot/cog-blindSpot/ https://michaelbach.de/ot/cog-blindSpot/ . I remember using other instruction/test image, but the result wa

You can try https://michaelbach.de/ot/cog-blindSpot/ https://michaelbach.de/ot/cog-blindSpot/ . I remember using other instruction/test image, but the result was quite clear - a dot in middle of image suddenly disappears, deepening on precise eye/head/screen orientation.