A pensioner said he was happy to leave hospital less than a week before he stabbed his wife to death and then himself, an inquest heard today.
Stanley Wilson, 92, had believed wife Peggie, 89, was trying to poison him and that other family members were in on the "plot", but was said to have changed his views in the days before the tragedy.
Their bodies were found in the front bedroom of their home in Kendal, Cumbria, on February 18 last year.
Former quarry worker Mr Wilson had started to lose his sight months before and had an operation for a detached retina at St Paul's Hospital in Liverpool after Christmas.
Relatives of the "devoted couple" and their neighbours told the hearing into their deaths yesterday that his behaviour drastically changed following surgery.
He was admitted to Royal Lancaster Infirmary on January 25 after his GP diagnosed "acute confusion".
Dr Martin Bethel recommended a hospital stay after he passed a note to his staff saying his family were trying to poison him and steal his money by altering his will.
Mr Wilson repeated the allegations to the GP and then to hospital staff whom he also accused of trying to poison him.
He was prescribed anti-psychotic drugs as part of his treatment and began to show signs of improvement in his condition, said consultant physician Dr David Walmsley.
On February 13 he was content to let his family visit him.
A day later he told a junior doctor that he had spoken to his wife and son Graham and stated his attitude had changed. He no longer wanted to change his will and was happy to go home.
Dr Walmsley said it was a "group decision" to discharge Mr Wilson on February 17.
The inquest at County Hall offices in Kendal has heard that Mr Wilson was treated with eye drops consisting of the steroid prednisolone as part of his post-operative treatment.
South Cumbria Coroner Ian Smith asked Dr Walmsley if the drops could have been the cause of his paranoid psychosis.
He replied that he was not an expert in the field and was speculating, but he thought it "virtually impossible".
"The amount of steroid in it must have been very low," he said. "My view is that it is not likely to be the cause."
Consultant psychiatrist Dr Alison Napier, from the Lancashire Care NHS Foundation Trust, who assessed Mr Wilson during his stay in hospital, also doubted whether the eye drops were a factor.
"There really is no evidence at the level I was looking at that the systemic absorption of eye drops could cause these symptoms," she said, "but it is well known that prednisolone can do that if taken orally."
Mrs Wilson suffered multiple injuries at their address in Mint Dale with numerous knife wounds to the neck - one of which severed her jugular vein - and blunt trauma injuries to the face and head, consistent with punching.
There were also signs that she had been asphyxiated.
Mr Wilson died from self-inflicted knife wounds, with many to the neck.