1.50 Standard Plastic vs 1.60 Thin Lenses: Exactly How Much Thinner and Lighter Is It?

In ophthalmic lens manufacturing, 1.60 resin (specifically Mitsui MR-8) bends light more sharply than standard CR-39:

$$n_{\text{MR-8}} = 1.60 \quad \text{vs.} \quad n_{\text{CR-39}} = 1.50 \implies \mathbf{\Delta n = +0.10 \implies 20-25\% \text{ Reduction in Sagittal Depth (Thickness)}}$$

Here is what that looks like in real millimeters for a typical $-4.00\ \text{D}$ prescription in an average $50\ \text{mm}$ frame:

• Standard 1.50 CR-39: Edge thickness $\approx \mathbf{5.2\ \text{mm}}$ (Heavy, noticeable protrusion from frame).
• ELLASUV 1.60 MR-8: Edge thickness $\approx \mathbf{3.9\ \text{mm}}$ (Flush, sleek fit within almost any frame).

While 1.67 and 1.74 lenses are even thinner, 1.60 MR-8 is celebrated by optical scientists as the ultimate all-around material because it makes zero compromises:

\begin{cases} \mathbf{\text{Abbe Value (Clarity):}} & \mathbf{V_d = 41} \ (\text{Vastly clearer than Polycarbonate 30 or 1.67 MR-7 32}) \\ \mathbf{\text{Tensile Strength:}} & >80\ \text{kgf} \ (\text{Unmatched drill-mount & rimless durability}) \\ \mathbf{\text{UV Absorption:}} & \mathbf{100\% \text{ UV400 built-in}} \ (\text{Standard 1.50 only blocks up to 355 nm}) \\ \mathbf{\text{Thermal Stability:}} & T_g = 118^\circ\text{C} \ (\text{Coatings never peel or craze under summer heat}) \end{cases}

• Powers under $\pm 1.75$ D: Standard 1.50 plastic is fine if budget is your only concern, though 1.60 still provides superior UV protection and scratch resistance.
• Powers from $\pm 2.00$ D to $\pm 4.50$ D: 1.60 is the absolute sweet spot. The reduction in edge thickness and weight is immediately visible, and your glasses will feel noticeably lighter on your nose throughout the day.