New multifocal lenses for presbyopia
Schönkirchen, 15 April 2016. The number of people with presbyopia is steadily increasing. Until now, because of intolerance or adjustment issues, conventional multifocal contact lenses were not a serious alternative to glasses for many of those affected. The new CONTACT INDIVIDUAL . MULTI from Wöhlk Contactlinsen GmbH can now be worn unproblematically by 90 per cent of those with presbyopia. The highlight: thanks to its innovative design, the lens can be perfectly adjusted to the individual beam path through the eye. Opticians can easily determine the necessary measurement data as part of their initial examination with no additional effort.
‘Those with customers who, until now, have been unsuccessful with multifocal contact lenses should therefore recommend they try again with the CONTACT INDIVIDUAL. MULTI,’ explains Wöhlk’s managing director Lothar Haase. The multifocal lens, which has been completely technically revised, has been exclusively developed by the contact lens manufacturer from Schönkirchen. Wöhlk, as the only supplier in Germany, employs an in-house research team here that continues to develop innovative materials and designs on the basis of customer feedback, among other things.
Research to optimise the multifocal lens has shown that almost no pupil actually sits exactly centrally in relation to the cornea. Rather, a mean horizontal pupil decentralisation of 0.34 mm OD and 0.32 mm OS towards the nose was ascertained as part of a study. When using conventional multifocal lenses, these variations often lead to irritation, intolerance, or double vision and ghosting.
By contrast, the central visual zone in the CONTACT INDIVIDUAL. MULTI can be individually adjusted to the wearer so that the lens sits reliably centrally in front of the pupil. Contrary to specially fitted lenses that require more effort on the part of the optician, as well as higher costs for the customer, a new type of functional engraving in the CONTACT INDIVIDUAL. MULTI ensures optimal position control for the central zone in front of the pupil. The engraved lines are located 2.5 mm from the midpoint of the central zone and are not only extremely discreet; they can also be used for spherical multifocal lenses with a centralised central zone.
In order to centre the multifocal lens in front of the pupil, the optician can determine the pupil’s position in relation to the cornea during the initial examination. In the process, he/she is able to ascertain the degree of decentralisation using various methods: imaging procedures, wherein the measurements can be collected digitally, offer optimal precision – video slit lamps or topographic systems, for example. Opticians who do not possess a digital measuring system can alternatively use the Wöhlk diameter template. This allows them to easily establish the appropriate value by comparing the defined standard decentralisation value with the pupil position.