Troubleshooting Intermediate/Computer Glasses

An eye exam gives you two numbers: one for distance vision, and one for near vision. But here’s the problem: most people live their daily lives somewhere in between those two spots.

If you spend hours on your phone or computer, your standard “near” prescription probably isn’t designed for how you really use your eyes.

Let’s break down how to design intermediate and computer eyeglasses that actually work for modern life.

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The Problem with Standard Add Powers

Most add powers are designed for a working distance of 16 inches (about 40 cm) - perfect for reading a book up close, but way too close for a computer screen.

Think about it: do you really sit just 16 inches from your monitor? Probably not.

Why So Many Progressives Fail for Computer Use

Many people get prescribed progressives:

  • Distance vision on top
  • Near vision on the bottom
  • Intermediate “corridor” in between

In theory, you just tilt your head to find your sweet spot. But in practice? If you’re juggling multiple monitors, the corridor is often too narrow. You end up hunting for focus all day, moving your head around just to see the screen. It’s exhausting - and it doesn’t have to be this way.

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What to Know When Designing Computer Glasses

Step 1: Find the Actual Working Distance

How far does your patient sit from their screen? Measure it if you have to.

Step 2: Adjust the Add Power

Here’s a simple formula:

  • Standard near is 16 inches.
  • Divide 16 by the actual working distance in inches.
  • Multiply that by the original add power.

Example:
Your patient works at 32 inches with a +2.00 add.

16 ÷ 32 = 0.5
0.5 × 2.00 = 1.00

So instead of a +2.00 add, you’d prescribe +1.00 for that distance.

Doctor making notes. Close up of eye doctor making notes while writing prescription for patient

How to Apply This in the Rx

Say the patient’s base prescription is +0.50 with a +2.00 add.

For computer use:

  • Increase the distance part by the adjusted add: +1.50 (0.50 + 1.00)
  • Keep the near add as needed, or adjust to give flexibility.

This “splits” the add power for intermediate tasks, widening the usable zone in the lens.

Lowering the add power widens the intermediate corridor in a progressive. A +1.00 add means a much larger, more comfortable area for the eyes to move around - perfect for scanning big screens or multiple monitors.

Don’t Forget Fitting Height

Your patient’s gaze angle matters.

When you measure fitting height:

  • Don’t just use standard straight-ahead measurements.
  • Factor in their natural head tilt and eye angle for their workstation.
  • Lower the fitting height if they naturally look downward at their screen.

This keeps them looking through the right zone without uncomfortable head movements.

What Lens Designs Work Best?

There are tons of so-called “office” or “computer” lenses out there. Some are great - but not all factor in real-world working distance or gaze angles.

In general:

  • Near-focused progressives widen the intermediate and near zones - better for office tasks.
  • Distance-focused progressives prioritize distance vision - not ideal for dedicated computer work.

If you know the exact design, pick a near or office design for a wider corridor and better comfort.

The Bottom Line

Designing computer glasses that truly work means:

  • Measuring real working distance
  • Adjusting the add power properly
  • Choosing the right lens design for wider intermediate zones
  • Aligning the fitting height with how your patient really sits

Don’t just stick to the numbers on the exam sheet - design for real life.