Christopher Lindsey, 28, who was released from East Mississippi in July, said in an interview that he had gone blind after months of not receiving appropriate treatment for the glaucoma he has had since childhood.

“I was crying in the cell, my eyes were hurting, bloodshot red, and I was slowly losing my eyesight,” he said.

Willie Hughes, 49, who was released in December, said in an interview that an infected sore on his leg had become gangrenous from neglect while he was in prison, and that a doctor had told him after his release that he narrowly escaped needing amputation.

The 1,362-bed facility is one of five private prisons in the state system; Mississippi, like other states, has turned to private operators to cut costs. But advocacy groups that oppose the trend say the for-profit companies often economize at the expense of inmate and public safety. They point to private prisons in several states that have had problems with violence, abuse or escapes that official reports attributed to understaffing, lax security and poorly trained corrections officers.

In a deposition given in March to the lawyers for the plaintiffs in the lawsuit, Matthew Naidow, a shift captain at East Mississippi, said that conditions at the prison had improved since M.T.C. took over the contract from the GEO Group, but that low wages and high staff turnover contributed to the persistence of security problems and corruption, which he said were more prevalent than at other prisons where he had worked. Corrections officers at the prison, he said, are paid around $10 an hour.