Lenticular & Myodisc Lenses: Advanced Blended Surfacing for Prescriptions Above -15.00D

A Myodisc separates the spectacle lens into two distinct concentric optical zones:

1. Central Optical Aperture (The 'Bowl', approx. 28mm to 32mm diameter): Contains the full $-15.00\ \text{D to } -30.00\ \text{D}$ corrective power carved onto the back surface. Because the aperture diameter is small ($y = 15\ \text{mm}$), edge thickness at the bowl rim is held under $4\text{--}5\ \text{mm}$.
2. The Carrier Zone: Extends from the margin of the central bowl out to the frame rim. The carrier has zero optical power (plano) or a flat base curve, reducing edge thickness at the frame bevel to just $2.5\text{--}3.5\ \text{mm}$.

Historically, traditional myodiscs possessed a sharp, razor-like circular ridge dividing the bowl from the carrier, creating a noticeable 'bullseye' appearance. Modern ELLASUV Digital Blended Lenticulars utilize CNC 5-axis polynomial spline smoothing:

$$\text{Spline Transition Zone: } \Delta r = 3\text{--}5\ \text{mm} \quad [C^2 \text{ Surface Continuity}]$$

This continuous mathematical transition blends the high-minus bowl smoothly into the carrier, making the boundary virtually invisible in social interactions while slashing total lens weight by over 65%.

At extreme powers, vertex distance changes dramatically alter effective refractive power according to the formula:

$$F_{\text{lens}} = \frac{F_{\text{cornea}}}{1 - d \cdot F_{\text{cornea}}}$$

A patient requiring $-20.00\ \text{D}$ at a $12\ \text{mm}$ vertex distance requires only $-16.67\ \text{D}$ if the lens is fitted at a $10\ \text{mm}$ vertex distance! Reducing frame vertex distance by 2 mm saves over 3.00 Diopters of raw lens thickness.