«ثُمَّ فَتَحَ كَرِيمَتَيْهِ»
Then he opened his two eyes.
When Abū Zayd opens his eyes, the earlier appearance of blindness is overturned. Karīmatayhi is a respectful circumlocution for the two eyes.
The elaborate request for washing supplies becomes another manoeuvre. The episode demonstrates deception through both spoken rhetoric and staged physical condition.