首楞嚴義疏注經 2.594

2.594

喻迷真起妄也。故，事也，瞪直視貌，不由別事，只因自不動目，直視於空，目睛勞倦，遂見華相。或見毛輪、第二月等，故云一切。色陰亦爾，以不如實知真如法一故，不覺動念，現六塵境，即色陰起也。

This metaphorizes giving rise to the false from delusion about the true. 'Reason' (gu) means an affair. 'Staring' (deng) describes looking straight ahead. Not caused by any other affair, merely because one keeps one's own eyes still and looks straight into space, the pupils become fatigued and weary, and one consequently sees appearances of flowers. Or one sees hair rings, a second moon, and so forth; hence it says 'all kinds.' The aggregate of form is also like this: because one does not know the unity of the dharma of tathatā in accordance with reality, one unknowingly stirs thought and manifests the spheres of the six dusts, which is the arising of the aggregate of form.