Lens Thickness

The material selected for a lens is fundamental, as it determines both comfort and clarity of vision.

The thicknesses of the lenses

In­dex­es and ma­te­ri­als

Lens Thick­ness

The ma­te­r­i­al se­lect­ed for a lens is fun­da­men­tal, as it de­ter­mines both com­fort and clar­i­ty of vi­sion. It’s com­mon­ly be­lieved that the greater the cor­rec­tion, the thick­er the lens, but this isn’t ex­act­ly how it works. To be sure you’ve cho­sen just the right lens, you need to take var­i­ous fac­tors into ac­count, such as lifestyle, work­place, home en­vi­ron­ment, and the frames of your eye­wear. You of­ten don’t need the thinnest lens if your frame doesn’t re­quire it. In the same way, you shouldn’t be too set on a spe­cif­ic type of frame if it isn’t right for the lens that is best suit­ed to your needs. Eye­wear frames are typ­i­cal­ly di­vid­ed into the fol­low­ing cat­e­gories:

  • Rim­less (or “glas­ant”) : These frames fea­ture a bridge, nose pads, and tem­ples with re­lat­ed hinges at­tached to the lens­es by way of screws or pins. Holes or grooves are cut into the lens­es.
  • Semi-rim­less (or “ny­lor”) : Half way be­tween rim­less and full-rim frames, semi-rim­less frames sup­port the up­per part of the lens with a metal­lic or plas­tic ma­te­r­i­al, while the low­er por­tion is held up by a ny­lon thread fed through a groove cut into the low­er edge of the lens.
  • Full rim : These are the most tra­di­tion­al frames and come in a range of ma­te­ri­als (e.g. ac­etate, met­al, ti­ta­ni­um al­loys) and shapes.

These are the main ma­te­ri­als DI­V­EL ITALIA and oth­er man­u­fac­tur­ers use to make lens­es:

  • MIN­ER­AL – This refers to tra­di­tion­al glass, which is less com­mon than it once was be­cause it is both high­ly frag­ile and heav­ier than lens­es made from “or­gan­ic” ma­te­ri­als. Nonethe­less, these lens­es may still be found on the mar­ket be­cause of their high de­gree of scratch re­sis­tance. PROS: scratch re­sis­tance. CONS: frag­ile

  • OR­GAN­IC – Plas­tic lens­es, such as the CR 39, are the most com­mon type of lens. They are more com­mon than min­er­al glass be­cause they are thin­ner, lighter, and more re­sis­tant. They also pro­vide high-qual­i­ty vi­sion thanks to the range of re­frac­tion in­dex­es avail­able. The CR 39 is the best suit­ed to be­ing tint­ed due to its lim­it­ed col­or dis­per­sion. PROS: light­weight, high per­for­mance. CONS: re­quire pro­tec­tive treat­ments.

Most lens­es on the mar­ket to­day are made of an or­gan­ic ma­te­r­i­al, not min­er­al glass. Each type of ma­te­r­i­al cor­re­sponds to a dif­fer­ent re­frac­tion in­dex. The high­er the in­dex, the thin­ner the lens. DI­V­EL ITALIA pro­vides lens­es in the fol­low­ing ma­te­ri­als:

Ind. 1.50 (clas­sic CR 39) Our 1.500 ma­te­r­i­al has ex­cel­lent op­ti­cal qual­i­ties thanks to its par­tic­u­lar­ly high Abbe num­ber(58). It is suit­ed to all col­ors and mir­ror types and is two times lighter than a tra­di­tion­al min­er­al lens.

Ind. 1.56 Our 1.560 ma­te­r­i­al is 20% thin­ner than a stan­dard lens (ind. 1.500 CR-39) and can be pro­duced in any col­or tone or in­ten­si­ty up to a max­i­mum of 75%. It is suit­ed to low and mid-range pre­scrip­tion strengths. Also avail­able in FO­TO­COL­OR and FO­TOCHRO­MA.

Ind. 1.60 Our ind. 1.600 ma­te­r­i­al is 30% thin­ner than a stan­dard lens (ind. 1.500 CR-39). It is the most rec­om­mend­ed for any type of frame, and its high Abbe num­ber makes it com­fort­able in all op­ti­cal sit­u­a­tions.

Ind. 1.67 Our ind. 1.670 As­pher­ic is 40% thin­ner than a stan­dard lens (ind. 1.500) and can be pro­duced in any col­or tone or in­ten­si­ty up to 75%. It is rec­om­mend­ed for all frame types and is par­tic­u­lar­ly suit­ed to glas­ant rim­less frames.

Ind. 1.70 1.710 As­pher­ic SILKEN LASER-THIN is our new ma­te­r­i­al with a re­frac­tive in­dex of 1.710 and su­per-thin, as­pher­ic de­sign. Falling be­tween our 1.670 and 1.740 in­dex lens­es, it unites the best of both worlds in terms of ver­sa­til­i­ty, ef­fi­cien­cy, cost, and aes­thet­ics. Our 1.710 LASER-THIN lens­es fea­ture an as­pher­ic geom­e­try in or­der to en­sure min­i­mal thick­ness even at high­er pre­scrip­tion strengths (45% thin­ner than a stan­dard 1.50 CR-39). On a par with our 1.740 lens­es, the high re­frac­tive in­dex en­sures su­pe­ri­or aes­thet­ics com­pared to low­er in­dex­es while main­tain­ing the ex­cel­lent ver­sa­til­i­ty of 1.670-in­dex lens­es. Fi­nal­ly, our 1.710 LASER-THIN lens­es pro­vide the most ad­vanced pro­tec­tion stan­dards out of the box, en­sur­ing to­tal UV ab­sorp­tion to­geth­er with the best coat­ing to sig­nif­i­cant­ly re­duce glare, keep away dirt and grime, and in­crease scratch re­sis­tance.

Ind. 1.74 Our 1.740 As­pher­ic ma­te­r­i­al is the thinnest shat­ter-re­sis­tant lens on the mar­ket. In high pre­scrip­tion strengths, it no­tice­ably re­duces the eye-mag­ni­fi­ca­tion ef­fect thanks to its very high re­frac­tive in­dex. It is 50% thin­ner than a stan­dard lens (ind. 1.500) and three time thin­ner than a high-in­dex min­er­al lens.

  • POLY­CAR­BON­ATE – This high­ly re­sis­tant, resin-based ma­te­r­i­al is most com­mon­ly used for sports eye­wear be­cause of its light weight and high im­pact re­sis­tance. It also pro­vides full pro­tec­tion from UV RAYS. PROS: im­pact re­sis­tance. CONS: vi­sion qual­i­ty is not com­pa­ra­ble to that of oth­er ma­te­ri­als.
  • SPE­CIAL MA­TE­RI­ALS – Our spe­cial ma­te­ri­als in­clude Fo­tochro­ma. Di­v­el Italia pho­tochromic lens­es come in six fash­ion col­ors (green, gray, pink, pur­ple, brown and blue) with an in­dex of 1.56 as well as in gray with an in­dex of 1.61. The par­tic­u­lar char­ac­ter­is­tic of pho­tochromic lens­es is that they are able to re­act to changes in light­ing con­di­tions, dark­en­ing or light­en­ing with changes in light. These lens­es are suit­ed for peo­ple who of­ten have to go back and forth from in­doors to out­doors. PRO : avoid chang­ing glass­es. CONS: dif­fi­cult to choose the col­or, you will want to have them all!

  • ECO MA­TE­RI­ALS – Di­v­el Italia’s GREEN LINE is an en­vi­ron­ment-friend­ly plas­tic made from 40% bio-ma­te­r­i­al that en­sures ex­cel­lent vi­su­al per­for­mance. It is cur­rent­ly avail­able for sun­glass­es and is be­ing test­ed for cor­rec­tive lens­es. PRO : eco-friend­ly. CONS : i trat­ta­men­ti ap­pli­cati diminuis­cono un po' la per­centuale di ma­te­ri­ale bio.