This tool helps estimate initial Acuvue Oasys Multifocal contact lens parameters based on your spectacle prescription. It applies vertex distance compensation for higher prescriptions and suggests the appropriate ADD power category (LOW, MID, HIGH) based on your spectacle ADD.
Right Eye Spectacle Prescription
Left Eye Spectacle Prescription
General Parameters
Understanding Acuvue Oasys Multifocal Lenses
Acuvue Oasys Multifocal contact lenses are designed to provide clear vision at all distances – near, intermediate, and far – for people with presbyopia. They utilize a unique "Pupil Optimized Design" that takes into account the natural variation in pupil size across different age groups and refractive errors. This design ensures that the right amount of power is delivered to the right part of the eye, regardless of whether you're reading a book or looking at a distant object.
Key Parameters Explained:
Sphere (SPH): This is the primary power of the lens, correcting for nearsightedness (myopia, indicated by a minus sign) or farsightedness (hyperopia, indicated by a plus sign) for distance vision.
Add Power (ADD): This is the additional magnifying power needed for clear near vision, which compensates for presbyopia. Acuvue Oasys Multifocal lenses come in specific ADD power categories: LOW (+0.75D to +1.25D), MID (+1.50D to +1.75D), and HIGH (+2.00D to +2.50D).
Base Curve (BC): This refers to the curvature of the back surface of the contact lens. It needs to match the curvature of your cornea for a comfortable and stable fit. Acuvue Oasys Multifocal lenses typically come in a standard 8.4mm base curve.
Diameter (DIA): This is the overall width of the contact lens. Acuvue Oasys Multifocal lenses have a standard diameter of 14.3mm.
Vertex Distance: This is the distance from the front surface of your eye to the back surface of your spectacle lens. For higher spectacle prescriptions (typically beyond +/-4.00 diopters), this distance can significantly affect the effective power needed in a contact lens. The calculator accounts for this "vertex distance compensation" to provide a more accurate contact lens sphere power.
How the Calculator Works:
This calculator takes your spectacle prescription's sphere and add power, along with your spectacle's vertex distance, to suggest initial Acuvue Oasys Multifocal lens parameters. It performs the following adjustments:
Sphere Adjustment: For higher spectacle prescriptions, it converts the spectacle sphere power to an equivalent contact lens power, accounting for vertex distance.
Add Power Mapping: It maps your spectacle add power to the closest Acuvue Oasys Multifocal ADD category (LOW, MID, or HIGH).
Important Considerations:
Astigmatism: Acuvue Oasys Multifocal lenses are spherical multifocal lenses and do not directly correct astigmatism. If you have significant astigmatism, your eye care professional may recommend a different lens type or discuss the potential compromises.
Professional Fitting Required: This calculator provides an estimation for initial fitting purposes only. A comprehensive eye examination and professional contact lens fitting by an optometrist or ophthalmologist are essential to determine the most suitable lens parameters for your eyes, ensure proper fit, comfort, and optimal vision.
Trial Lenses: Contact lens fitting often involves trying different parameters and ADD powers to find the best balance of distance and near vision for your individual needs.
Always consult with your eye care professional before making any changes to your contact lens prescription.
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function roundToQuarterDiopter(value) {
return Math.round(value * 4) / 4;
}
function calculateContactLensPower(spectaclePower, vertexDistance) {
var d = vertexDistance / 1000; // Convert mm to meters
// No vertex compensation needed for powers between -4.00D and +4.00D
if (Math.abs(spectaclePower) < 4.00) {
return spectaclePower;
}
// Formula for contact lens power (Fc) from spectacle power (Fs) and vertex distance (d in meters)
// Fc = Fs / (1 – d * Fs)
var contactLensPower = spectaclePower / (1 – d * spectaclePower);
return contactLensPower;
}
function getAcuvueAddCategory(spectacleAdd) {
if (spectacleAdd <= 1.25) {
return "LOW (+0.75D to +1.25D)";
} else if (spectacleAdd 1.75
return "HIGH (+2.00D to +2.50D)";
}
}
function calculateAcuvueMultifocal() {
// Get input values
var sphRight = parseFloat(document.getElementById("sphRight").value);
var addRight = parseFloat(document.getElementById("addRight").value);
var sphLeft = parseFloat(document.getElementById("sphLeft").value);
var addLeft = parseFloat(document.getElementById("addLeft").value);
var vertexDist = parseFloat(document.getElementById("vertexDist").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
// Input validation
if (isNaN(sphRight) || isNaN(addRight) || isNaN(sphLeft) || isNaN(addLeft) || isNaN(vertexDist)) {
resultDiv.innerHTML = "Please enter valid numerical values for all fields.";
return;
}
if (vertexDist < 0) {
resultDiv.innerHTML = "Vertex Distance cannot be negative.";
return;
}
if (addRight < 0 || addLeft < 0) {
resultDiv.innerHTML = "Add Power cannot be negative for multifocal lenses.";
return;
}
// Calculate for Right Eye
var adjustedSphRight = calculateContactLensPower(sphRight, vertexDist);
var roundedSphRight = roundToQuarterDiopter(adjustedSphRight);
var acuAddRight = getAcuvueAddCategory(addRight);
// Calculate for Left Eye
var adjustedSphLeft = calculateContactLensPower(sphLeft, vertexDist);
var roundedSphLeft = roundToQuarterDiopter(adjustedSphLeft);
var acuAddLeft = getAcuvueAddCategory(addLeft);
// Display results
var resultsHTML = "
Suggested Acuvue Oasys Multifocal Parameters:
";
resultsHTML += "Right Eye:";
resultsHTML += "Sphere: " + (roundedSphRight > 0 ? "+" : "") + roundedSphRight.toFixed(2) + " D";
resultsHTML += "Add Power: " + acuAddRight + "";
resultsHTML += "Left Eye:";
resultsHTML += "Sphere: " + (roundedSphLeft > 0 ? "+" : "") + roundedSphLeft.toFixed(2) + " D";
resultsHTML += "Add Power: " + acuAddLeft + "";
resultsHTML += "Fixed Parameters for Acuvue Oasys Multifocal:";
resultsHTML += "Base Curve (BC): 8.4 mm";
resultsHTML += "Diameter (DIA): 14.3 mm";
resultsHTML += "Disclaimer: This is an estimation for initial fitting. Always consult an eye care professional for a precise prescription and fitting.";
resultDiv.innerHTML = resultsHTML;
}