Owner Peter S. Dick said it was a special occasion.
''It's a real milestone.
''It's been a father/son thing.
''Things have changed a bit and we've embraced that with enthusiasm,'' he said.
Peter Dick Optometrists was opened in Dunedin in 1915 by Mr Dick's great-grandfather as a combined jewellery and optical business.
The business continued through Mr Dick's grandfather and father, who focused it more on optics, before Mr Dick joined the business in 1992.
Over the years, the practice had catered for a wide range of people.
One client, 99-year-old Dorothy Hardy, had been looked after by three generations of the family and was its ''oldest and longest'' client.
''She came to us in the 1930s [and] she needed glasses most of her life,'' Mr Dick said.
''She was good friends with my grandfather.
''We've got a lot of patients in their 90s that have been with us for decades,'' he said.
''We got to know them really well.''
Mrs Hardy was invited to the celebration but was unable to attend through ill health.
Mr Dick said it was the people who made the business what it was today and they were a highlight and a key to its longevity.
As well as its Moray Pl practice, Peter Dick Optometrists has a branch in Mosgiel and has regular scheduled visits to Cromwell and Ranfurly.
