Michael Scott, who denies deliberately running over his aunt while reversing an agricultural teleporter, had perfect vision in his left eye, but his brain had learned to ignore his weaker right eye, the Central Criminal Court has heard.
Trina Staunton on Friday told prosecution counsel Dean Kelly SC that in 2017 she was an optometrist with Specsavers in Nenagh and Mr Scott came to see her on June 28 that year.
His left eye scored a perfect six out of six, but his right eye was much weaker and scored six out of 38, she said. The right eye, she said, was being "ignored by the brain".
Children can be treated for a weak eye using patches or glasses but if that is not done or is unsuccessful, the brain ignores the weak eye and only focusses on the good eye to prevent the person suffering double vision.
You only need vision in one eye to qualify for a licence to drive a car, motorbike or tractor, she said. Mr Scott's peripheral vision was normal.
Under cross-examination Ms Staunton agreed with defence counsel Paul Greene SC that once Mr Scott had reached adulthood, treatment on his weaker right eye would be ineffective.
She further agreed that when looking over the right shoulder while reversing there is a, "limit to the assistance the good eye can give to the bad eye".
Under re-examination, the witness told Mr Kelly that Mr Scott knew that his right eye was weak and that if Mr Scott turned around while reversing he would be able to see using his left eye.
Tragic accident
Michael Scott (58) of Gortanumera, Portumna, Co Galway has pleaded not guilty to murdering Ms Treacy outside her home in Derryhiney, Portumna, Co Galway on April 27th, 2018.
The prosecution alleges that Mr Scott deliberately ran over his aunt following a long-running dispute over land. Mr Scott's lawyers have said Ms Treacy's death was a tragic accident.
Kenneth Power told Mr Kelly that he rented land at Kiltormer, not far from Ms Treacy's home, that had previously been leased from Ms Treacy by Mr Scott.
On April 23rd that year damage was done to his electric fences and the tops were taken off the batteries that powered the fence, leaving the poisonous lead exposed and causing a danger to his cattle. "Luckily they didn't go near it," he said.
About six weeks later he received a phone call from Mr Scott who appeared to be "slightly agitated" but was not shouting or roaring.
Mr Power said he wouldn't have rented the land if he knew that the previous farmer still had an interest in it and told Mr Scott that he rented it from a local agricultural consultant.
Mr Scott described the consultant as "a bollox" and accused him of "spreading rumours about me". Mr Scott said he would "get him or do him or words to that effect," the witness recalled.
Mr Scott also mentioned the damage that had been done to Mr Power's electric fences and said: "When would I get time to be at that?" Mr Power said it was clear from the question that somebody had suggested that Mr Scott was responsible for the damage but Mr Power did not know who had made that suggestion.
James Egan told Mr Kelly that Ms Treacy was a lifelong friend of his mother and he knew her all his life.
In the months before her death he became closer with Ms Treacy, and she would often call him on the phone for a chat. When he visited her home around this time, he sometimes found her crying and "most unhappy".
Cold weather
In the weeks before her death the calls became more frequent and on one occasion when unseasonably cold weather and heavy snowfall had been forecast in the late spring of 2018, she called him with a concern about her oil-fuelled range.
The house, which Ms Treacy normally kept hot, was "bitterly cold" when Mr Egan arrived. He found the range to be in good working order, but it appeared not to be getting oil. When he checked the tank he found that the tap was almost completely closed. When he opened it, the range fired up as normal.
Mr Egan said he took the view that the tap at the oil tank had been "deliberately screwed to almost closed" causing the oil to stop or reduce to a trickle.
He said he didn't tell Ms Treacy what he had found as she "didn't need to hear this". Every day during the storm that followed Mr Egan called into Ms Treacy with a cooked meal.
Mr Egan agreed with Mr Greene that a technician had serviced the range a few days prior to him finding the almost fully closed tap.
Wade O'Meara told Mr Kelly that he works for Phonewatch and installed an alarm system with cameras and sensors at Ms Treacy's home in early February 2018.
While he was there a slim, middle-aged man with a beard asked him what he was doing. He described the man as being "in a rant and trying to get information" about what he was installing and how it worked.
He said he felt that the man was "trying to suss out" where the components of the alarm were going and was particularly interested in what was being put upstairs in Ms Treacy's home. He asked a few times if there were sensors going upstairs.
The man asked about cameras going outside, pointed to a corner of Ms Treacy's house and told Mr O'Meara: "There better not be cameras going up over there."
The trial continues in front of Ms Justice Caroline Biggs and a jury of seven men and eight women.
