1.56 Semi-Finished Flat Top Bifocal Lens

Flat-top lens were used to correct two different eye prescriptions. Bifocals were easy to spot – they had a line dividing the lens in two, with the upper half for distance vision, and the lower half for reading. The semi-finished lens are produced in a casting process. Here, liquid monomers are first poured into moulds. Various substances are added to the monomers, e.g. initiators and UV absorbers. The initiator triggers a chemical reaction that leads to hardening or “curing” of the lens, while the UV absorber increases the UV absorption of the lens and prevents yellowing.

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1.56 flat-top semi-finished optical lens
Model:	1.56 optical lens
Place of Origin:	Jiangsu, China
Brand:	SETO
Lenses Material:	Resin
Bending	200B/400B/600B/800B
Function	flat-top & semi-finished
Lenses Color	Clear
Refractive Index:	1.56
Diameter:	70
Abbe Value:	34.7
Specific Gravity:	1.27
Transmittance:	>97%
Coating Choice:	UC/HC/HMC
Coating color	Green

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