LAWRENCE — The father of a baby girl has been sent to jail for three and a half years for shaking his infant so violently that doctors believed she'd be blind for life.

The baby, eight weeks old at the time of the assault, has regained her sight, but could face medical problems down the road, said Lawrence police Detective Lt. Mary Bartlett.

Juan Cabrera, 20, of Framingham, admitted shaking the baby twice in February.

Cabrera pleaded guilty to two counts of assault and battery on a child under 14 causing serious bodily injury last week in Salem Superior Court.

During a hearing in which he waived his right to a jury trial, Cabrera told Judge Timothy Feeley he had been treated for mental illness, including bipolar disorder, but was not presently being treated.

Prosecutor Kate MacDougall said when police arrived at the home the baby was not responsive and frothing at the mouth.

MacDougall said it was determined the baby had a fractured spine.

Cabrera, wearing a black hooded sweatshirt, agreed to the facts as MacDougall presented them.

MacDougall asked the court to sentence Cabrera to four years and a day in state prison.

Defense lawyer Carol Cahill, from the Committee for Public Counsel Services, asked Feeley to impose a sentence of two and a half years followed by lengthy probation due to his age.

She told the court that Cabrera was a graduate of the Lighthouse School in Chelmsford and that he was never taught how to care for his baby daughter.

Police and emergency medical personnel were called to the apartment Feb. 11, for reports the baby girl was not breathing.

She was taken to Boston Children's Hospital where it was discovered she had bleeding on the brain, a broken vertebrae, several bruises, and new and old retinal hemorrhages.

Questioned at the hospital on Feb. 12, Cabrera admitted to shaking the baby three to five times a few weeks previous while the baby's mother was out shopping.

She told the court that Cabrera had no malice toward his daughter and that he was the one who called 911 on the night she was taken to the hospital.

She said Cabrera also understands how lucky he is in that the baby has recovered.

Cabrera refused to make a statement to the court prior to sentencing.

He also was ordered to take parenting classes and to comply with orders of the Department of Children and Families.

Bartlett said the baby, who it was feared would be permanently blind, had regained her eyesight, but there were concerns for her future gross motor skills when it was time for her to learn to walk and talk.

Bartlett said the baby was presently living with her mother in a state-supervised residential home in Newburyport, and that she remains in the custody of the Department of Children and Families, which is responsible for her care.

The mother of the baby could not be reached for comment for this story.