Sforno on Genesis 27:22/ספורנו על בראשית כ״ז:כ״ב

1והידים ידי עשו. There can be no question that the skins had been prepared in such a fashion that the hair on them were just like the hair on human skin, for in its natural state the hair on goatskin is considerably different from that on a human skin. What the Torah testifies to then is that Yaakov’s hands now were just as hairy as the hands of Esau. It is quite possible that not only Yitzchok’s eyesight had deteriorated to the point where it did not serve him to identify objects with any degree of certainty, but that also his sense of touch had become weakened as a source of identifying objects he touched. Samuel II 19,36-37 would support this where Barzilai lists a number of his faculties which suffered weakness as a result of old age.