NK55 Advanced Varifocal Lenses , 28mm Segment 1.56 Varifocal And Bifocal Lenses Flat Top

28mm Segment 1.56 NK55 Uncoated Flat Top Bifocal Lenses For Varifocal Vision
 
I. Specifications:

	Refractive Index: 1.56
	Monomer: NK55, imported from Japan
	Abbe Value: 40
	Specific Gravity: 1.20
	Transmission: 96%
	Coating: uncoated
	Diameter: 70mm
	Flat Top Segment: 28mm
	Power Range: SPH:0.00~+3.00,0.00~-3.00,CYL:+1.00~+3.50

II. Flat Top Bifocal Lenses:

• Why Need The Bofical Lenses?

The aging process includes changes in vision that makes everyday reading more difficult than usual because of the loss of one’s ability to focus naturally. This condition is called presbyopia. It is often relieved by wearing special reading glasses. People who have been wearing prescription eyeglasses because of nearsightedness or farsightedness will need bifocals or eyeglasses with two different lens powers to help them see objects at different distances.

Bifocals have two different lens powers that aid in seeing objects at various distances once the aging process reduces your ability to do so. These are usually prescribed to adults older than 40 years, although some children and younger adults may also need them for focusing problems, which strain the eyes while reading.

How Do Bifocal Lenses Work?   A flat top bifocal may be thought of as a round segment with the top cut off. In this design the optical center of the segment is located closer to the transition line, producing less image jump. Flat top segments are also called straight top bifocals and are occassionally referred to as D segments since they are shaped lik the letter D. If the lens on the previous page were a flat top design, the optical center of the segment would be only 4 mm from the transition line rather than 11 mm.

Flat Top bifocals are available if the following diameters: FT-28. The variety of sizes is possible due to the ability to manipulate the position of the optical center of the segment relative to the transition line. Since the optical center of round bifocals are always in the geometric center of the segment, they are commonly available in the relatively small 28mm diameter and are ordered as “28 Round.” Although larger diameters are available, more image jump is produced. The patient desiring a larger segment might be well advised to select another style lens.

III. Bifocal Catalog:

IV. Our Factory:

V. Packing:

1. Envelope:

a) standard white envelope

b) color envelope with customer design (Weight: 157g, Size: 9*9*9cm)

2. Outer Box

a) standard export paper carton (Size: 38*48*35cm, 0.064CBMS)

b) Include about 500 pairs of finished lens (Weight: about 21kg) or include about 100 pairs of 100 semi finished lens (Weight: about 15kg)

VI. Shipping:

1. Samples:

a) Delivery time: 3-7 days (by Fedex, DHL, UPS, TNT etc.)

b) Sample is free, but accroding to our company rule, the shipping cost need to be assumed by customers.

2. Batch Goods:

a) Delivery time: 10-30 days (depend on your quantity, by air, sea or express)

b) Carrier: We can choose for you or offer us your cooperative company