Lens Materials

Choosing lens material changes how glasses look, feel, and perform. Two specs matter a lot: Abbe value (clarity/dispersion—higher is crisper, fewer colour fringes) and Specific Gravity (density/weight—lower is lighter on the face). Refractive index affects thinness: higher index usually means a slimmer edge for the same prescription.

Need help matching material to your Rx, frame style, or usage (safety, sport, kids)? Our lab is happy to recommend the best fit.

Material	Refractive Index	Specific Gravity, g/cm³	Abbe Value	Est. Thickness, mm (-4.00 sph, 50 eyesize)	Best for
Plastic	1.5	1.31	59	5.6	Low Rx, best optics, easy tinting
	1.56	1.23	37	4.7	Slimmer than 1.5 at moderate Rx
	1.6	1.30	41	4.5	Higher Rx thinning with solid optics
	1.67	1.37	32	4.1	High myopia thinning
	1.70	1.41	36	4.0	Very high Rx, ultra-thin
	1.74	1.47	33	3.9	Max thinness for extreme Rx
Polycarbonate	1.59	1.20	30	4.5	Impact protection, kids, safety, Drill-mounts
Trivex	1.53	1.11	44	4.8	Drill-mounts, sport, lightest feel
HiVex	1.56	1.25	46	4.7	Balanced optics, durability and tintability

Note: The estimates above are for −4.00 sph @ 50 mm eyesize. At higher powers (e.g., −6.00 @ 54 mm), the thinness advantage of higher-index materials increases further. Actual thickness also depends on frame shape, PD, base curve, wrap, and lens design.

Material	Refractive Index	Specific Gravity, g/cm³	Abbe Value	Est. Thickness, mm (-4.00 sph, 50 eyesize)
Plastic	1.5	1.31	59	5.6
	1.56	1.23	37	4.7
	1.6	1.30	41	4.5
	1.67	1.37	32	4.1
	1.70	1.41	36	4.0
	1.74	1.47	33	3.9
Polycarbonate	1.59	1.20	30	4.5
Trivex	1.53	1.11	44	4.8
HiVex	1.56	1.25	46	4.7

Lens Materials

Material

Refractive Index

Specific Gravity, g/cm3

Abbe Value

Est. Thickness, mm (-4.00 sph, 50 eyesize)

Best for