The headword phrase (in which "grayness" pertains to gray hair) is presumably quoted from somewhere. Lodewijk Caspar Valckenaer (1715–1785) suggested emending the headword to the genitive polia=s "of grayness"; then "of old age" would be a gloss in the same case. The genitive polia=s is usually feminine of the adjective polio/s, but is occasionally attested as from the noun polia/.
For "of old age," the editio princeps of Demetrius Chalcocondyles (1499) reads gh/rws, genitive of gh=ras (more common than gh=ros).
[1] Similar glossing in Hesychius (and Etym. Magn 680.16).
[2] cf. alpha 4102.