Rodenstock's Impression FreeSign progressive lens was the preferred choice in an independent study of more than 100 presbyopes.
The field study conducted by the Swiss Federal Institute of Technology in Zurich tested three individual free-form lens types and one classic lens design with 105 randomly selected patients.
Every patient wore each of the four lenses for three weeks, while objective and subjective data were collected. Those taking part were required after 15 minutes of wearing to assess comfort, adoption of the lens, quality of vision in general and for near, far and distance.
They were then also asked to perform popular binocular and monocular acuity tests for far and near distance. They were also questioned about the need to move their head while using the lens, the duration of their daily work and duration of time at the computer. These same questions were posed after one hour, three days and three weeks.
The report stated that 'more and more complex needs and preferences are considered in lens design such as the co-ordination of eyes and head'.
It also noted that those who had previously worn progressive lenses were more sensitive to the difference in quality.
Rodenstock's Impression FreeSign lenses were reported to provide the best user satisfaction and were voted 'significantly superior'. Rodenstock generates an estimated 36 per cent of world sales in the individual lens category.
