"Do Not Go Gentle into that Good Night"- simile

"Old age should burn and rave at close of day."  This line is from the poem "Do No Go Gentle into That Good Night" by Dylan Thomas.  In my opinion, it is one of the most challenging poems of the seven.  The line that started this blog I took as meaning that sometimes a reason for someone's death is just simply old age.  "Do not gentle into that Good night."  I think this line means do not leave me or pass away.  "Blind eyes could blaze like meteors and be gay..."  This is an example of a simile.  It is comparing the eyes to meteors.  I really could not understand most of this poem.  Frankly, I am a bit confused!