1.The characteristics of photochromic lenses Photochromic lenses are available in nearly all lens materials and designs, including high indexes , bifocal and progressive. An added benefit of photochromic lenses is that they shield your eyes from 100 percent of the sun's harmful UVA and UVB rays. Because a person's lifetime exposure to sunlight and UV radiation has been associated with cataracts later in life, it's a good idea to consider photochromic lenses for children's eyewear as well as for eyeglasses for adults.4. What is the difference between HC, HMC and SHC？

Hard coating	AR coating/Hard multi coating	Super hydrophobic coating
makes the uncoated lens hard and increases the abrasion resistance	increases the transmittance of the lens and reduces surface reflections	makes the lens waterproof, antistatic, anti slip and oil resistance

1.56 photochromic progressive optical lens
Model:	1.56 optical lens
Place of Origin:	Jiangsu, China
Brand:	SETO
Lenses Material:	Resin
Function	Photochromic&progressive
Channel	12mm/14mm
Lenses Color	Clear
Refractive Index:	1.56
Diameter:	70 mm
Abbe Value:	39
Specific Gravity:	1.17
Coating Choice:	SHMC
Coating color	Green
Power Range:	Sph: -2.00~+3.00  Add: +1.00~+3.00

2.The Characteristic and Advantange of Progressive Lens Progressive lens, sometimes called "no-line bifocals," eliminate the visible lines of traditional bifocals and trifocals and hide the fact that you need reading glasses. The power of progressive lens changes gradually from point to point on the lens surface, providing the correct lens power for seeing objects clearly at virtually any distance.3.Why we choose the photochormic progressive? Photohromic progressive lens also has the advantages of photochromic lens ①It adapts to environmental changes (indoor, outdoor, high or low brightness). ②It provides greater comfort, since they reduce eyestrain and glare in the sun. ③It is available for most prescriptions. ④It provides daily protection against harmful UV rays, by absorbing 100% of UVA and UVB rays. ⑤It allows you to stop juggling between your pair of clear glasses and your sunglasses. ⑥It is available in different colours to suit all needs.