Nicholas Dryland was not wearing contact lenses the day he crashed into a group of cyclists, killing one and seriously injuring two others.
Judge Philip Connell said Dryland's failure to wear correcting lenses was a breach of his licence and a contributing factor in the crash, which killed cyclist Craig Goulsbro and seriously injured William Donaldson and Christopher Smith.
Dryland, 22, was travelling east in Puketaha Rd about 6.20pm on July 1 when he attempted to overtake a group of 10 cyclists.
During the manoeuvre, Dryland swerved back into the lane to avoid an oncoming car and collided with four cyclists.
He later told police he thought there was only two riders ahead of him.
Judge Connell said Dryland's "deliberate" decision not to comply with the conditions of his licence and wear corrective lenses was a contributing factor in the crash.
Dryland was yesterday sentenced in Hamilton District Court to 12 months' jail, disqualified from driving for 2 and a half years and ordered to pay $11,000 reparation.
He had earlier pleaded guilty to a charge of aggravated careless use of a vehicle causing death and two of aggravated careless use of a vehicle causing injury.
Judge Connell declined a request to impose a sentence of home detention, saying Dryland's previous convictions for "bad driving" indicated a disregard for other road users. He was convicted of careless driving in 2008, 2009 and 2012.
The judge said the driving convictions indicated Dryland was either a "grossly incompetent driver" incapable of making safe judgement calls, or a reflection of the fact Dryland was devoid of any consideration for others.
A pre-sentence report indicated Dryland was at medium risk of reoffending.
Police prosecutor Sergeant Andrea McBeth said Dryland's offending had profoundly affected Mr Goulsbro's family and friends.
It had also caused serious injuries to cyclists Mr Donaldson and Mr Smith.
Ms McBeth said Dryland's victims had been vulnerable as cyclists riding on the open road.
Dryland had appeared not to have been deterred by his previous convictions for careless driving, Ms McBeth said, and pointed to comments made by Dryland's mother to a Waikato DHB staff member just after the July 1 crash. Ms Dryland said her son drove like an "idiot".
In reply, lawyer Thomas Sutcliffe said the fatal crash was the result of a "one-off momentary lack of judgement".
He said his client was remorseful but, because of Dryland's mental limitations, this might not have been expressed clearly to the pre-sentence report writer.
Dryland had "completely misjudged the situation" when he attempted to overtake the group of cyclists and took full responsibility for the tragic crash.
Speaking outside court, Mr Goulsbro's older brother, Lance Goulsbro, said his family were satisfied with the jail sentence but it did not give them closure.
"Craig is gone and nothing is going to bring him back."
Mr Goulsbro said he did not know if Dryland was remorseful for his brother's death, but said he had sympathy for Dryland's mother.