Computer Glasses Prescription Calculator

Computer Glasses Prescription Calculator

Convert your standard distance prescription into optimized intermediate (computer) lenses.

Example: -1.25 or +2.00

Example: -1.00 or +1.75

This is the "ADD" value found on your progressive or bifocal prescription.

Your Computer Lens Results

Right Eye (OD)

Left Eye (OS)

Note: CYL (Cylinder) and AXIS values remain identical to your original prescription.

function calculateComputerLens() { var sphOD = parseFloat(document.getElementById('sphOD').value); var sphOS = parseFloat(document.getElementById('sphOS').value); var add = parseFloat(document.getElementById('addPower').value); if (isNaN(sphOD)) sphOD = 0; if (isNaN(sphOS)) sphOS = 0; if (isNaN(add)) add = 0; // Computer lenses (intermediate) are typically the SPH plus half of the ADD power var computerAdd = add / 2; var finalOD = sphOD + computerAdd; var finalOS = sphOS + computerAdd; function formatPower(num) { var sign = num >= 0 ? "+" : ""; return sign + num.toFixed(2); } document.getElementById('resOD').innerHTML = formatPower(finalOD); document.getElementById('resOS').innerHTML = formatPower(finalOS); document.getElementById('comp-results').style.display = 'block'; }

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Understanding Computer Glasses Prescriptions

If you spend more than two hours a day looking at a digital screen, you may experience Digital Eye Strain. Standard reading glasses are usually designed for 12-16 inches (30-40 cm), while distance glasses are for everything beyond 10 feet. Computer monitors typically sit in the "intermediate zone"—roughly 20 to 30 inches from your eyes.

How the Intermediate Calculation Works

The math for computer glasses is straightforward for most people with a multifocal prescription. To find the intermediate power, we take your Sphere (SPH) and add 50% of your Add Power (ADD). This adjusts the focal point specifically for the distance of a desktop monitor or laptop.

Example Calculation

Let's look at a typical prescription for a user with presbyopia:

• Distance SPH: +1.00
• ADD Power: +2.00
• The Logic: 50% of the ADD (+2.00) is +1.00.
• Computer Prescription: +1.00 (Original SPH) + +1.00 (Half ADD) = +2.00 SPH

Why Not Just Use Reading Glasses?

Reading glasses are too strong for a computer screen. Using them for computer work often forces you to lean closer to the screen to get it in focus, leading to "turtle-necking," which causes neck and shoulder pain. Conversely, distance glasses are too weak, causing you to squint or strain to see text clearly.

Key Features of Computer Lenses

• Wider Field of Vision: Unlike progressives, single-vision computer glasses offer a large, clear area for the screen without having to tilt your head.
• Blue Light Filtering: Many computer glasses include a coating to reduce high-energy visible (HEV) light.
• Anti-Reflective Coating: Essential for reducing glare from office lighting and screens.

Important Medical Disclaimer: This calculator provides an estimate based on standard optical formulas. It is not a substitute for a professional eye exam. Always consult with an optometrist or ophthalmologist before ordering new eyewear, especially if you have high astigmatism or complex vision needs.