People with eye disease gather around a health worker to register for free eye examination and treatment at a hospital in Amran, Yemen, Oct. 31, 2020. Yemen's health authorities launched on Saturday a free medical campaign for patients with eye disease in Amran province. The campaign aims to alleviate the suffering of the needy and poor families and will last for six days. (Photo by Mohammed Mohammed/Xinhua)

A health worker helps a patient to have his eye checked during a free medical campaign for patients with eye disease at a hospital in Amran, Yemen, Oct. 31, 2020. Yemen's health authorities launched on Saturday a free medical campaign for patients with eye disease in Amran province. The campaign aims to alleviate the suffering of the needy and poor families and will last for six days. (Photo by Mohammed Mohammed/Xinhua)

People wait to receive free eye examination and treatment at a hospital in Amran, Yemen, Oct. 31, 2020. Yemen's health authorities launched on Saturday a free medical campaign for patients with eye disease in Amran province. The campaign aims to alleviate the suffering of the needy and poor families and will last for six days. (Photo by Mohammed Mohammed/Xinhua)

People with eye disease gather around a health worker to register for free eye examination and treatment at a hospital in Amran, Yemen, Oct. 31, 2020. Yemen's health authorities launched on Saturday a free medical campaign for patients with eye disease in Amran province. The campaign aims to alleviate the suffering of the needy and poor families and will last for six days. (Photo by Mohammed Mohammed/Xinhua)