Guo Bin, aided by a doctor at Shanxi Eye Hospital in Taiyuan, tries to walk during a rehabilitation training program that started on Sunday.[ZHANG YUN / CHINA NEWS SERVICE]

DNA tests show that Guo Bin's blood was found on Zhang's clothing, according to police. Zhang was identified as the assailant by combining the DNA test with other police investigations.

No motive for the assault has been disclosed.

Guo Bin, whose parents are farmers, went missing at 6 pm on Aug 24, when he failed to return home from playing outside at his usual time to eat dinner. After a 5-hour search, he was found lying in a field, his face-bathed in blood.

When it was discovered at a local hospital that the boy's eyes were missing, he was sent to Shanxi Eye Hospital in Taiyuan, the provincial capital, that same night.

The next day investigators found the boy's eyes near where he had been found bleeding.

Fenxi county police posted a notice on Aug 27 offering a reward of 100,000 yuan ($16,340) for information leading to the arrest of the assailant, who they said was a woman.

On the morning of Aug 30, the victim's aunt Zhang Huiying committed suicide by jumping into a well.

Zhang's suicide soon sparked suspicion that she was the assailant, but this was denied by the boy's father, Guo Zhiping, who said the two families had a good relationship.

Aside from the loss of his eyesight, Guo Bin is now out of danger, his father said.

Doctors plan to give the boy artificial eyes for the sake of his appearance.

Guo's mother, Wang Wenli, said three Hong Kong eye specialists visited her son in the hospital and said Guo Bin's vision might be partially restored by implanting electronic ocular prostheses.

One of the Hong Kong eye surgeons said he would perform the operation on Guo Bin for free, according to Wang.

Donations have been flowing into the family since reports of the attack hit the headlines last week. Guo Zhiping said the amount has reached 800,000 yuan ($130,500).