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Focus on lenses

Focus on lenses

  • What are the best type of lenses for high levels of short-sightedness? Open

    If you are very short-sighted, your spectacle lenses can feel thick and heavy and make your eyes appear smaller. High index materials have been developed which allow your lenses to be thinner and lighter. Ask the dispensing optician to talk to you about better lens materials and designs.

  • What are the best sort of lenses for high levels of long-sightedness? Open

    If you are very long-sighted, your spectacle lenses can feel thick and heavy and magnify your eyes. Aspheric lens designs can thin and flatten the lens, reducing the magnifying effect. High index materials have been developed which allow your lenses to be thinner and lighter. Ask the dispensing optician to talk to you about better lens materials and designs.

  • What is a lenticular lens and who might it help? Open

    Some people with very high spectacle prescriptions benefit from lenticular lenses. The part of the lens that helps you to see better is in the centre, within a wider border of clear lens, giving a shape like a fried egg. This cuts the central thickness of the lens and ensures the specs are lighter.

  • What is a slab-off bifocal and who might it help? Open

    A slab-off lens can help if you have a difference between your two eyes, and also need different powers of spectacle lens for distance and near vision. This can lead to an imbalance between the two eyes when you try to read. The slab-off technique can be applied to bifocal and varifocal lenses. By altering the angle at which one lens is ground you can avoid the lenses inducing double vision.

  • What is a Franklin split lens and who might it help? Open

    Franklin split lenses are special bifocals which provide a very wide zone for near vision. They are produced by cementing together two lens halves, one the distance portion and one the near portion. They can help people who have a difference between their two eyes to avoid vertical jump or imbalance.

  • What are freeform lenses? Open

    Freeform lenses use computer-aided design and surfacing to create high-level, customised spectacle lenses with your unique prescription. They can help to reduce glare and halo effects caused by light sources at night, such as car headlights.

  • How are freeform lenses made? Open

    To create freeform lenses, once you have chosen a frame, the registered dispensing optician will fit the frame to your face. They will then scan your eyes using specialised equipment that measures your face and eye position. They will also measure how the frame sits in front of your eyes, how it wraps around your face, and even how you tilt your head.  The software combines your physical data with your spectacle prescription in order to provide the best vision, day and night. The optician will send your order direct to an optical lab. Your lenses will be created on a computer-driven, free-form generator. This machine is able to work to extremely high levels of accuracy and can generate more complex surface shapes than traditional glazing equipment. The lenses are then fitted to your frame. Finally, the registered dispensing optician will readjust the frame for the best fit on your face.

  • Why should I choose freeform lenses? Open

    Freeform lenses use an advanced manufacturing technique which reduces aberrations in spectacle lenses. You may not notice spectacle lens aberrations, or if you have a high prescription and high index lenses you may have noticed a coloured tint to the periphery of what you can see when you are looking away from the centre of your lens. Advances in lens manufacturing mean that lenses can be made without these aberrations. If you want sharper vision, or suffer from glare and problems with night vision, talk to a registered dispensing optician about freeform lenses.

  • Who will benefit from freeform lenses? Open

    Anyone can benefit from freeform lenses, but you will find most benefit if you have a high prescription, if you are bothered by glare or your vision seems indistinct. Make sure that you have had a recent eye examination, then talk to a registered dispensing optician about freeform lenses.

  • What lenses are best for children’s specs? Open

    Children should always have plastic lenses in their glasses. You can ask for polycarbonate or Trivex lenses which are lighter, thinner and tougher than regular plastic lenses. They also offer 100 percent protection from harmful UV light. An antireflection coating on the lenses can give your child clearer vision. You can get prescription sunglasses for children, or you can opt for photochromic lenses which darken on exposure to sunlight so your child doesn’t need to think about swapping from one pair of specs to another.