The term emmetropia defines an eye without visual defects able to correctly focus images and make light rays converge at the point of focus.
When this ability of the eye is lost, we are in presence of cases of ametropia, visual defects of various nature in which the point of focus is positioned in front or behind the retina causing blurry images.
Usually, carriers with high ametropies such as myopia, hyperopia, astigmatism and presbyopia, are forced to wear glasses with very thick and heavy lenses that can compromise normal daily activities.
LTL has designed an entire range of free-form lenses produced with special techniques that allow ultra-thin customizations able to satisfy high quality and aesthetic standards at the same time.
Extra Care Lenses: new joints for reduced thicknesses
In order to correct the visual disturbances caused by ametropia, in the past were used lenses which presented a graduated central area with a high refractive power and a non-graduated peripheral zone of neutral power. The peripheral zone was realized not graduated to try to reduce to the minimum the thickness of the lens, which however was equally thick. The innovative aspect of EXTRA CARE lenses is the possibility to reduce the lens thickness to make it adaptable to all frame types, without any restrictions.
The range is divided into three types: soft, medium and hard. In these lenses the attribute soft, medium and hard refers to the level of hardness of the fittings, which influences the final thickness. In other words, the passage from the non-graduated optical zone to the graduated optical zone is balanced in the soft, defined in the medium and net in the hard.
Let compare the technical characteristics of traditional As Free Forms with the new solutions offered by Extra Care lenses.
The edge of the lens presents a new generation multi-spherical joint created by maintaining an ideal relationship between visual comfort and thickness reduction, with an optical zone, called “bowl”, variable from 20 to 50 mm, which shows up in a round, elliptical or variable shaped depending on the frame.
Highly effective and aesthetically
In the ophthalmic world, in general, when you are in presence of an high prescription there are inevitable production limitations such as:
- High thicknesses for both positive and negative lenses
- Hardly eliminable aberrations
- Very heavy lenses to bear every day
- Need for special care in centering the lens as prismatic corrections may arise
- Limitation in the choice of frames
- Waiver of aesthetic quality
EXTRA CARE lenses exceed these limits, reaching very high quality and aesthetic standards.
To whom are they recommended
EXTRA CARE lenses have been designed for all people with medium and high ametropies and guarantee a defined vision by compensating the distortions generated by the high curvature of the lenses.