Mr McGiven first visited the optometrist on December 9, 2010 when he was 16.
But the healthcare professional did not know what the abnormality was and did not record the condition, a retinal detachment, as a diagnosis in his clinical notes.
The teenager attended a second appointment on December 16 when more photographs of his eye were taken. He was advised to return in three months for more photos.
It was not until February 7, 2011, or about eight weeks after the first consultation, that the optometrist faxed a referral letter to ophthalmologist Dr Brian Kent-Smith.
The referral letter did not mention the first consultation on December 9 nor were photos taken that day sent to Dr Kent-Smith who promptly diagnosed a right retinal detachment and arranged for surgery.
But by then it was too late, and Mr McGiven's eye had to be removed.
Dr Kent-Smith and another ophthalmologist, Dr Philip Polkinghorne, both agreed the optometrist should have referred the teen immediately.
However, the Northland optometrist said it was a genuine mistake due to misfiling of records.
He maintained that stance during yesterday's tribunal hearing, although he accepted his failure to identify the detached retina and to promptly refer Mr McGiven to an ophthalmologist.
Tribunal deputy chairwoman Kate Devonport said that although charges of malpractice and negligence against the optometrist had been established, he would face suspension instead of having to pay a fine.
The optometrist has also been ordered to pay $10,000 in costs to the tribunal.APN
