He told the inquest he began wearing specialist glasses in the months after the accident.
Despite holding a truck driver's licence for 15 years, he said he had driven "an over-dimensional truck", on this occasion hauling a bulldozer and hay bales, for just two.
He also admitted to driving on a road that he didn't use regularly.
Mr Boulcott said he allowed "at least half a truck" in between the vehicle he was driving and two cyclists prior to coming across the group Mrs Farrelly was in.
But one of those cyclists, Diane Cunningham, yesterday gave evidence that contradicted this. She laid a complaint with Taupo police about her close encounter with Mr Boulcott.
The inquest before Coroner Gordon Matenga will hear from four more witnesses after Mr Boulcott completes his evidence today.