What are contact lenses made of?

Many people around the world wear contact lenses to correct their vision, to improve their appearance and to protect their eyes from worsening visual impairment. The success of contact lenses is linked to their relatively low cost, comfort, effectiveness and safety.

Contact lenses - what do you need to know?

What are contact lenses made of? While contact lenses of the past were made of glass, modern lenses are already manufactured from technologically advanced polymers. Pierwsze contact lenses były twarde i wykonane ze szkła. Modern soft lenses are made of hydrogel and silicone hydrogel polymers. Hard contact lenses are made of polymethylmethacrylate (PMMA) or Plexiglas, while soft lenses are produced polymer gels that allow oxygen permeability.

Soft contact lenses are now available in both hydrogel and silicone hydrogel. As the formulation of lenses has improved, so has the type of lens care solution. Multifunctional solutions help to moisten lenses, disinfect them and prevent protein deposits. Most commonly, patients choose daily disposable, bi-weekly, monthly and annual lenses. Daily disposable lenses do not require care as they need to be discarded after each use. With contact lenses, patients can feel comfortable and relaxed, as well-fitting lenses are not felt during wear. Discomfort can, however, be felt when inserting them. How can a patient recognise if their lenses are unsuitable? Firstly, when they are inserted, the patient feels that they are on their eyes. Secondly, when moving the eyeballs, the lenses move much slower than the eyes. Ill-fitting lenses can also cause eye redness, itching and stinging. If this happens, it is important to see an eye doctor immediately and raise your concerns with them about the type of lens used.

Before fitting contact lenses for the first time, patients should familiarise themselves with their lens care regimen and instructions for use to ensure that they fully meet the needs of the wearer. Do not forget that lenses are a medical device and should be used in accordance with the instructions. They are an excellent alternative to corrective spectacles, but you can't do without proper lens care. What's more, fitting lenses on your own is too risky, so you should see a specialist for this, just as you do with contact lenses. The specialist will select the appropriate lens power, radius of curvature and diameter.

Twarde szkła kontaktowe są mniej wygodne niż miękkie, za to mogą korygować szerszy zakres wad wzroku, szczególnie u pacjentów z dużymi wadami wzroku i astygmatyzmem.

Hybrydowe soczewki łączą w sobie specjalistyczną korekcję wzroku soczewek sztywnych z komfortem soczewek miękkich. Soczewki hybrydowe mają twardy środek otoczony pierścieniem z miękkiego materiału. Te nowsze soczewki mogą być używane do korekcji astigmatism i nieregularności rogówki.

What are contact lenses made of? Methods of contact lens manufacture

Hard lenses are usually custom-made, whereas soft lenses are mass-produced. There are three methods of lens manufacturing. Here are the three categories:

• Spin Casting - the liquid silicone is spun on a rotating mould, where it polymerises.

• Moulding - the liquid polymer is injected into a rotating mould. Centripetal force gives the lens its shape as the plastic polymerises. Moulded contacts are wet from start to finish. Most soft contact lenses are made using this method.

• Diamond turning (lathe cutting) - an industrial diamond cuts a polymer disc to shape the lens, which is then polished with an abrasive. Both soft and hard lenses can be shaped using this method. Soft lenses are moistened after the cutting and polishing process.

Which lenses to choose? To improve the quality of your vision, you need to see a specialist who can help you with both lens and contact lens selection. He or she will know what the contact lenses are made of and will fit the right lenses for your needs and your visual impairment. Although hard contact lenses are less comfortable than soft contact lenses, they can correct a wider range of visual defects, especially in patients with severe visual impairment and astigmatism. Hybrid contact lenses combine the specialised vision correction of rigid lenses with the comfort of soft lenses. It is almost impossible to select lenses on your own without specialist knowledge!