Tried and tested: Rodenstock DNEye Impression FreeSign 3 Lenses

Lens manufacturing has been transformed by the introduction of digital surfacing technology. Lenses can now be surfaced to a far greater degree of accuracy than most eye examinations are conducted to. But no longer.

Rodenstock is hoping to leverage the accuracy of its lens manufacturing capabilities by introducing new readings into the eye examination through its DNEye scanner. Among other things it measures dioptres to two decimal points rather than the more usual quarter divisions.

The data from the DNEye scanner is collected alongside a traditional subjective eye examination. The patient looks into the scanner, much like an autorefractor, indeed the DNEye includes an objective refraction. It also uses wavefront aberrometry to provide differences in refraction at distance and near and under normal and low light conditions. The higher order aberrations detected are then manufactured into the Freesign 3 lens. In this case a difference in spherical and cylindrical correction was found under low light conditions and a cylinder was also added to the near additional power. Pupil diameters were measured at 2.6mm and 3.6mm. Aberrations tend to increase with pupil size.