Pioneers in plastic filters
– Dad’s little business was located in an old paper mill, in the home of the former factory caretaker. That’s where he started testing different pigments. He had a small hob and pots with coloring mixture, and dipped the plastic lenses until he found the right colours, says his son Björn Hellström.
First out were ML511, ML527 and ML550. They cut off the same light as Corning's versions, but since then Multilens has developed a wide range of own filter colours, such as ML450, ML500, ML585 and C1. Several of them were so successful that attempts have been made to copy them – not least the popular C1 filter that is often used for sunglasses.
– Our first filters effectively absorbed all unwanted light, but users sometimes experienced that the colour vision changed too much. That's why we developed the C1 filter, which retains color vision better and feels a little softer, says Björn.
– We worked together with an optician named Carl Otto Ahlström and first the filter was called CO1, but when more opticians became involved in the development, we simplified the name to C1, which also stands for Comfort.
Contrast, comfort, protection
In the early days of filters, most people talked about the contrast-enhancing properties. Today, the message is more about comfort and the patient's own experience. But filters also provide protection and that is why the ML400 was invented.
– It is usually said that UV light ends at about 400 nm and therefore we wanted to cut the light there, says Björn. This was simply our way of UV-treating the glass – we put on a light 400-colour for protection, with a small dose of comfort.
So where is the filter technology going now?
– I think we will see more broken filter colours, ie filters that select the light, but with a small amount of gray or brown colour for a more aesthetic effect. I also think we will see more variants of filters for people with neurological symptoms or who suffer from brain fatigue for various reasons. And we will continue to explore how filters in different ways can make us feel better!