If in my youth I had realized that the sustaining splendour of beauty of with which I was in love would one day flood back into my heart, there to ignite a flame that would torture me without end, how gladly would I have put out the light in my eyes.

The line expresses a characteristically Renaissance tension between the rapture of beauty and the pain of desire. Looking back from old age, the speaker imagines that youthful delight in beauty later returns as an involuntary, consuming memory—no longer sustaining but tormenting. The wish to have “put out the light in my eyes” is a hyperbolic renunciation of sight itself, suggesting that perception (especially of physical beauty) can become a lifelong wound. Read in a Michelangelesque key, it also echoes his recurring poetic theme: earthly beauty awakens longing that can either elevate the soul toward the divine or trap it in restless, unending passion.