If you require a corrective prescription for your vision then you may wish to have both clear optical lenses for normal use and prescription sunglasses for sunnier condition. At Pretavoir we offer prescription sunglasses for the vast majority of our sunglass frames. Indeed if you wish you can also have prescripton sunglass lenses fitted to frames otherwise intended for clear optical lenses. All of our prescription (also referred to as Rx) sunglass lenses offer full UV protection. There are a number of other considerations such as;
Lens Type: Single Vision or Varifocal. If you are over 40 yrs old then you may require a different prescription for distance and reading. If this is the case then many will prefer to have one pair of glasses becoming both prescriptions in one lens. This is achieved by selecting a varifocal lens. We can supply and fir varifocal lenses to all presciption friendly sunglasses however it is not possible to order directly and you should contact us for such an order. However, in the case that you require your glasses to have single vision lenses then you can progress to the next step..
Lens Brand: There are many manufacturers of spectacles lenses and as with product brands a range of qualities and prices. We offer three lens brands to cater for our customers needs. The entry level WLC brand offers a great price point and products of good quality. The mid level Kodak brand offers a mid price point and lenses of higher than average quality. Finally, the best lenses available are manufactured by the famous Zeiss company. This brand is know for its precision opticcal products such as microscopes and telescopes aswell as the best camera lenses. This heritage of excellence is evident in the un paralleled quality of the Optical Lens product portfolio. If you want the best and are prepared to pay a little more then Zeiss lenses will be your choice.
Lens Index: If you have a relatively strong prescription where the spherical value ie the first number shown is greater than +/- 2.50 then you may wish to consider choosing a thinner material. The standard material is 1.5 index whilst 1.6 and 1.67 are thinner options, 1.6 reducing lens thickness by 25% and 1.67 material by a further 25% approximately. It is also worth noting that 1.6 and 1.67 matericals are also more impact resistent than the basic 1.5 index material.
Polarised Lenses: These lenses have a special chemical applied to them to filter light. The chemical's molecules are lined up specifically to block some of the light from passing through the lens. An analogy often used is that of a window / venetian blind; only light that passes through the blind's openings can be seen. All reflected light is selectively blocked, therefore harsh reflections from shiny surfaces are removed. Many premium brands offer this lens type including Ray Ban, Gucci, Cartier and many more. The Maui Jim brand offers only polarised lenses and indeed it is likely that the majority of lenses will be polarised at a future time.. Pretavoir offers three dark tint colours with Polarisation; Grey, Brown and Green.
Lens Tint: In non polarised lens options we offer six different lens colours; Brown, Grey, Green, Yellow, Pink and Purple. This is often a matter of personal preference and related to frame colour. For example if you are choosing a black sunglass frame then you may wish to have a grey or dark green lens rather than grey whilst if you are choosing a brown frame then you may consider that a brown tint is most suited. Grey lenses tend to produce a cooler tone whilst brown lenses cast a warmer tone.
Gradient Lens: This lens is darkest at the top portion in which your distance vision is located. The tint reduces in level to a lighter more transparent level at bottom of lens. It is often chosen for aesthetics however others prefer for its functionality eg for driving the gradient means that the dashboard appears brighteror if you intend to read a lot with your sunglasses then you may prefer a lighter tint through which to read.
Back Surface Anti Glare Coating: The final element to the very best sunglass lens is the inclusion of back surface anti glare / anti reflection coating. This property ensures the very best visual comfort by eliminating distracting reflections bouncing from the back surface of the lens into your eyes. Many premium non prescription lenses from brands such as Maui Jim, Serengeti have this feature as standard and we are now able to offer this option on prescription lenses should you wish to add the finishing touch to a your sunglasses.