12-12-2015  (47 ) Categoria: Articles

Lents-Bifocals

Els lents bifocals contenen dues prescripcions diferents a la mateixa lent. El propòsit principal dels bifocals és proporcionar l'equilibri òptim entre la visió a distància i les necessitats de visió centrant-se d'aprop. Aquests lents estan disponibles amb els segments de lectura en una varietat de formes i amples, incloent opcions d'ulleres de sol. La forma dels bifocals llegir més popular és el Flat-Top (també coneguda com a recta superior o segment D), que és d'uns 28 mm d'ample. WLC ofereix una sèrie d'opcions per a l'usuari de lents bifocals.

How to view through a bifocal lens

SHAPES OF BIFOCAL LENSES

AVAILABILITY IN BIFOCAL
INDEX
Clear
Color
Type
Addition
Power Range
1.67 Plastic Clear D28 1.00 to 3.00 -15.00D/ +7.00D
1.60 Plastic Clear C28 1.00 to 3.50&4.00
-15.00D/ +7.00D
-8.00D/ +8.00D
1.60 Plastic Clear D28 1.00 to 3.00 -12.00D/ +8.00D
1.59 Polycarbonate Clear D28 0.75 to 4.00 -12.00D/ +9.00D
1.53 Trivex Clear D28 1.00 to 3.50 -8.00D/ +7.50D
1.50 CR 39 Clear C28 0.75 to 3.50&4.00 -12.00D/ +10.00D
1.50 CR 39 Clear D28 0.75 to 4.00 -8.00D/ +7.50D
1.50 CR 39 Clear D35 0.75 to 3.50 -7.00D/ +7.00D
1.50 CR 39 Clear RT28 0.75 to 3.50 -6.00D/ +7.50D
1.50 CR 39 Clear Executive/RT 24 1.00 to 3.00
Transitions
Clear
Color
Type
Addition
Power Range
1.50 CR 39 1.53 Trivex C28/ D28 1.00 to 3.00 -8.00D/ +7.50D
1.50 CR 39 Grey D35 0.75 to 4.00 -6.00D/ +7.50D
1.53 Trivex Grey D28 1.00 to 3.00 -8.00D/ +7.50D
Polarised
Clear
Color
Type
Addition
Power Range
1.50 CR 39 Grey D28 1.00 to 3.00 -6.00D/ +6.00D
1.50 Polycarbonate Grey D28 0.75 to 3.50 & +4.00 -8.00D/ +6.50D
Drivewear
Clear
Color
Type
Addition
Power Range
1.50 CR 39 Brown D28 1.00 to 3.00 -8.00D/ +7.50D
Sunlite
Clear
Color
Type
Addition
Power Range
1.50 CR 39 Grey D28 1.00 to 3.00 -6.00D/ +6.00D
* Available upto 4cyl. only
Acclimates
Clear
Color
Type
Addition
Power Range
1.50 CR39 Grey/ Brown D28 1.00 to 3.00 -8.00D/ +7.50D
Mineral
Clear
Color
Type
Addition
Power Range
1.52 Glass White D28/ C28 0.75to3.50 -8.00D/ +6.00D
1.52 Glass PGX/ PBX D28/ C28 0.75to3.50 -8.00D/ +6.00D
1.52 Glass White RT 25/ RT28 0.75to3.50 -6.00D/ +6.00D
1.52 Glass PGX/PBX RT28/ RT28 0.75to3.50 -6.00D/ +6.00D
1.52 Glass White Executive 1.00 to 3.00 -5.25D/ +4.00D
1.52 Glass PGX/PBX Executive 1.00 to 3.00 -5.250/ +4.00D
MAX. +6.00 CYL.

 

Lens Type

Based on your prescription, the optician will choose from the following lens types: single-vision or a lens with two, three—or an infinite—range of powers.

Single Vision: This type of lens features one power throughout the entire lens. It is typically for people between the ages of 1 and 40 as it is used either to correct problems with distance or for special needs, including magnification. A single-vision lens can also be used for reading only.

 

Bifocal: A bifocal lens is equipped with two ranges of power—far and near. Bifocals are easily recognized by the line that separates the far range from the near range. For this reason, it is sometimes referred to as a line bifocal.

 

 

Trifocal: As the name implies, a trifocal lens has three, separate ranges of power—far, intermediate and near—marked by two, distinct lines. Like the bifocal, it’s easy to see the lines that differentiate between the three ranges.

 

 

Progressive: Blessed with an infinite number of focal points, this type of lens changes gradually so that it can adjust to a wide variety of distances. As a result, the user can see far, intermediate and near distances without any lines of demarcation.




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