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Dual Strength Bifocal - The Card Shark
$79.95
How to Choose Your Strengths
Choosing your powers is easier than it sounds. Here’s a simple way to think about it:
Step 1 – Start with what you already wear.
If you use two pairs today — one for the computer and one for reading — those are the same two strengths you’ll use in your Dual-Strength lenses: computer power on top, reading power on the bottom.
If you currently wear just one pair of readers, use that strength as your bottom (reading) power.
Step 2 – Choose a milder power for the top.
The top of the lens is made for computer and mid-range (arm’s-length) vision, so it should be weaker than your reading strength — similar to your “computer pair” if you already use one.
Step 3 – Why the difference matters.
Dual-Strength lenses work best when the top is at least
1.00 diopter weaker than the bottom.
This creates a smooth, comfortable transition from computer distance to close-up reading — without eye strain.
Step 4 – Fine-tune for your daily habits.
If you spend more time on the computer than reading, choose a gentler top power for relaxed, sustained clarity.
Here are a few example combinations that follow the required 1.00 diopter difference and offer smooth dual-distance clarity:
| Your usual readers | Suggested top (computer) | Suggested bottom (reading) |
|---|---|---|
| +2.50 | +1.50 | +2.50 |
| +3.00 | +2.00 | +3.00 |
| +3.50 | +2.50 | +3.50 |
| +4.00 | +3.00 | +4.00 |
Dual-Strength Bifocals vs. Progressive Lenses
Progressive lenses may promise seamless vision, but for many readers, they come with trade-offs that affect comfort, safety, and cost.
Long adjustment period: Progressives often require weeks of adaptation and can cause dizziness, headaches, or eye strain.
Dual-Strength benefit: Two clearly defined zones mean little to no adjustment—your eyes know exactly where to look.
Reduced peripheral vision: The narrow vision corridor in progressives can limit side vision, which may feel unnatural or unsafe while walking or driving.
Dual-Strength benefit: Full peripheral clarity with no distortion or swim.
Higher cost: Progressives are often significantly more expensive due to complex lens technology.
Dual-Strength benefit: $79 with free shipping—clear, predictable pricing.
Frame limitations: Progressives require taller frames, reducing your style options.
Dual-Strength benefit: Over 40 frame styles in multiple sizes, colors, and shapes—no compromises.
Why Dual-Strength Bifocals Just Work
- • Two clearly defined magnification zones for natural, predictable vision
- • Comfortable clarity for reading, computer work, and everyday mid-distance
- • Designed for immediate comfort — no learning curve
- • Thoughtfully engineered for daily wear, all day long
We’ve been designing and perfecting reading glasses for over 30 years. Every Dual-Strength lens reflects decades of hands-on experience listening to customers, refining fit, and focusing on what truly makes glasses easy to wear.
You’ve chosen the frame style. Next, you’ll personalize your pair by selecting the frame color, frame width, and lens strengths that suit how you see and live.
Choose your color, width, and powers below to complete your pair ↓
- SKU:
- en4200dualbf
- Weight:
- 1.10 Ounces
Description
Sharp, bold, and built for readers who always play to win.
Everyday Vision with a Competitive Edge
Meet The Card Shark, a sleek rectangular frame designed for readers who appreciate clean lines, modern angles, and practical comfort. With its versatile sizing and lightweight build, this frame brings professional polish to your daily reading routine.
Whether you're scanning documents, multitasking at work, or enjoying your favorite book, this design delivers clarity and style in equal measure.
Seamless Clarity with Dual-Strength Bifocal Technology
DebSpecs’ dual-strength bifocal lenses make shifting between tasks effortless.
Upper Zone – Intermediate / Screen Vision
• Softer magnification for computer use, meetings, and mid-range viewing
• Reduces eye fatigue during extended screen time
Lower Zone – Near / Reading Vision
• Stronger magnification for up-close clarity
• Ideal for reading, crafting, fine details, labels, and paperwork
Smooth transitions – no visible line, no interruptions.
Lightweight Plastic with Everyday Comfort
• Sleek rectangular silhouette for modern versatility
• Lightweight plastic frame suitable for long hours of wear
• Comfortable temple design for a secure, stable fit
• Available in two size options to accommodate more face widths
Fit & Measurements
Lens Width: 53 mm or 56 mm
Bridge: 17 mm
Temple Length: 140 mm or 145 mm
Face Width:
• Average – 125 mm
• Wide – 131 mm
Shape: Rectangle
Materials: Plastic
Target Customer: Unisex
Available Colorways
• Shiny Tortoise – warm and classic
• Black – clean and timeless
• Cobalt Blue – bold and modern
• See Through (Crystal) – fresh, minimalist clarity
• Matte Gray with Black Arms – understated, sleek, and refined
Perfect For
• Professional, everyday, and casual wear
• Readers who want a lightweight but durable frame
• Switching between screens and reading tasks
• A modern, no-fuss rectangle look
Why “The Card Shark” Is a Smart Upgrade
• Sharp rectangular design with wide size availability
• Smooth dual-strength bifocal reading comfort
• Lightweight, durable, and office-friendly
• Five versatile color options
Shipping & Production Notes
Frames may require 3–5 business days for final finishing before shipment.
Downloads
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11 Reviews Write a Review
-
perfect for work at home
Just what I needed. Works perfectly. Now I don't have to switch between glasses .
-
Nice glasses for folks who feel....
Nice glasses for folks who feel cheated when they go to the fancy eye places. These work well. with good optical quality. My only suggestion would be for a little less yellow intensity on the tint option.
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works for me
Works for me. Perfect for working at my computer. I got the 1.50/2.50. I just wish there was an extra wide option.
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Work great
I don't need two different strengh glasses, one pair for reading computer screen and reading close up for books etc. Really like them.
-
Great but did not work for me. Your milage may vary. Worth a look.
These are just want I needed post-cataract surgery. The folks here were helpful and shipping was fast. Sadly, the placement of the bifocal insert was just too low for my needs and I found myself looking through the top line much of the time. This will vary by individual so it may work fine for you. It is worth trying out! And the refund was swift and easy! Cheers