A South Carolina woman has been sentenced to 25 years in prison for killing her husband by poisoning his drinking water with eye drops for days.

Lana Clayton, 53-year-old, pleaded guilty to voluntary manslaughter and tampering with a food or drug. According to York County detectives, Lana Clayton admitted to giving her husband, Steven Clayton, drinks laced with Visine.

Prosecutors said that Lana intentionally poisoned her husband with Visine for three consecutive days before the poison eventually caused his death.

The woman told prosecutors that the husband was abusive, and she didn't mean to kill him. Instead, she only meant to "make him uncomfortable."

She said in court:

"I allowed these emotions to make me do something in a matter of seconds that I will forever regret. I did impulsively put the Visine in Steven's drink, and I did it with the intent to make him sick and uncomfortable… I never thought it would kill him."

Eye drops contain Tetrahydrozoline – an ingredient in over-the-counter eye drops. Just a few drops can be deadly if swallowed. Experts warn that you can't breathe after a while, your heart shuts down, and you eventually go into a coma.

Lana's lawyers, however, said she was a good person, having worked as a Veterans Affairs nurse in Charlotte.

They revealed that Lana was abused as a child, raped on a military base, and suffered from the post-traumatic stress disorder.

Court records show the couple lived on property worth more than $1 million, and Steven Clayton had over $1 million in other assets. He was a retired businessman from Florida.

Lana already knew the Visine would kill her husband, but continued to poison him, prosecutors said.

Judge Paul Burch told her in court:

"How can you maintain you did this to teach him a lesson when it is obvious from the facts that you let him suffer for three days? You ignored him."

Solicitors told the judge that Lana Clayton had killed her husband to inherit the money. They claimed that she burned his will and threw his phone in a lake so he couldn't call for help.

Before her arrest, Lana, Steven's seventh wife, tried to kill herself by taking pills and turning on the stove's gas. She had even written a suicide note.

The poisoning incidence wasn't the first time Lana tried to kill her husband.

Two years before the poisoning, she had shot her husband in the back of the head with a crossbow. It was ruled an accident at the time, but prosecutors now reportedly believe it was intentional.