High-Index Lenses: A Clear Vision Revolution

by , September 1, 2023

High-index lenses

Technology continues to transform the eyewear industry. High-index lenses crafted from novel materials have changed how we perceive the world. The technology provides those patients with strong eyeglass prescriptions an alternative solution to the thick, heavy lenses they have used in the past. High-index lenses are thinner, lighter, and prettier than ever before.

What are high-index lenses?

High-index lenses are a type of eyeglass lens material designed to be thinner and lighter than standard lenses made from materials like glass or plastic. High-index lenses are the thinnest, most-lightweight lenses available for high prescriptions and are typically only recommended for patients with higher prescriptions. High-index lenses provide the best optical clarity and improve the lens appearance for these patients. High-index lenses are available in different refractive index levels, such as 1.60, 1.67, and 1.74. The higher the index, the thinner the lens. As the refractive index increases, so does the cost of the lenses.

What Are High-Index Lenses Made Of?

High-index plastics are specialized materials designed specifically for high-index lenses. High-index lenses can be made from materials with a higher refractive index than standard lens materials. These plastics are developed to be thinner and lighter than standard plastic materials while providing excellent optics. High-index lenses often incorporate aspheric optics in their design. Aspheric lenses have various degrees of curvature across their surface, allowing for more precise correction of vision and reducing the distortion that often occurs with spherical lenses at higher prescriptions.

What Prescription Strengths Need High-Index Lenses?

High-index lenses are beneficial for those with a stronger prescription for nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Nearsightedness (Myopia): If you have a higher amount of myopia, your prescription will have a high negative diopter value (-4.00 diopters and above), and you will benefit from high-index lenses. High-index lenses will reduce your lens's thickness and weight, making your eyeglasses more comfortable to wear and improving appearance. Your lenses will appear less chunky at the edge. Farsightedness (Hyperopia): If you have a high amount of hyperopia, your prescription will have a high positive diopter value (+3.00 diopters and above). Lenses that correct for hyperopia are thickest in the middle of the lens, making the eye appear magnified and creating distortion. High-index lenses will allow for your prescription to be made thinner and lighter and reduce the effect of the magnification especially with the use of aspheric lens designs. Astigmatism: High-index lenses are also beneficial for those with higher amounts of astigmatism, which is an irregular corneal curvature. Your doctor may tell you your eye is like a football or an egg. High-index materials will correct your astigmatism and minimize distortions.

The Difference Between High-Index Lenses and Regular Lenses

The main difference between a high-index lens and a regular (plastic) lens is their refractive index. The refractive index is an optical property that measures how much light is bent or refracted when it enters a material from another medium. A higher refractive index means light slows down more as it passes through the material, causing it to bend more. The refractive index is important to consider when making glasses because it affects how thick or thin the lenses need to be in order to correct a specific level of vision. High-index lenses bend light more efficiently, making the lenses thin and lightweight.

The Advantages of High-Index Lenses

High-index lenses have many advantages.

  • Improved Appearance: One of the most important advantages of high-index lenses is their slim appearance. A thinner lens profile creates a more attractive and natural appearance for glasses wearers with a strong prescription. You don’t have to worry about your appearance and your lenses looking like "Coke bottle" glasses.
  • Reduced Distortion: High-index lenses reduce the amount of distortion from light passing through the lens, providing the lens wearer with sharp, clear vision.
  • Improved Comfort: High-index lenses are notably lighter than other lens materials, making them more comfortable for long periods of wear.
  • Extended Range of Prescriptions: High-index materials are necessary for those with stronger prescriptions (nearsightedness, farsightedness, or astigmatism). High-index lenses are much thinner for those with a stronger prescription.
  • Extended Range of Frames: If you purchase high-index lenses, you have more frame options, including metal, rimless and semi-rimless options.

The Disadvantages of High-Index Lenses

  1. Cost: Cost is the biggest disadvantage of a high-index lens. They are rarely covered on vision insurance plans and can be twice as much or more than a standard plastic lens. The increase in cost is due to the advanced technology and materials used in the manufacturing process.
  2. Glare: Some high-index materials have a higher reflective index, which may lead to increased glare and reflections around bright lights or using digital devices. This can be bothersome for some spectacle wearers.
  3. Delicacy: High refractive index materials can be brittle than standard plastic and polycarbonate lenses. They are more susceptible to cracking or shattering upon impact. Replacing lenses can be quite costly for patients who are active in sports or who are not as careful with their glasses. They are also extremely sensitive to hot temperatures. If you leave your high-index lenses in the car, they will crack and peel.

Is it Possible to Have High-Index Lenses in Sunglasses?

It is possible to have high-index lenses in your sunglasses. High-index lens materials are not limited to regular clear eyeglasses. They can also be used if you desire lightweight and thin sunglass lenses. Keep in mind that high-index lenses are not impact resistant for sports or activities with high-velocity objects like baseball or range shooting. High-index lenses are available in tinted or polarized options with UV protection.

Are High-Index Lenses Right for You?

If you are wondering about high-index lenses, you should ask your eye doctor if you are a good candidate. You should also consider your prescription strength, how you would like your lenses to look aesthetically, the importance of comfort and the weight of your lens to you, hobbies and activities, cost, and if high-index lenses may be more compatible with your frame choice.

Tips for Caring for High Index Lenses

The following 4 care tips can help extend your high-index lenses' life.

  1. Clean Regularly: Clean your lenses regularly to remove the accumulated dirt and oils. Use either soap and water or dawn dish detergent to clean your lenses, and avoid using harsh chemicals that can damage the coatings.
  2. Use a Designated Cloth: Wipe your lenses with a microfiber cleaning cloth designed for eyeglasses. Never use a T-shirt or Kleenex to clean your lenses; the fibers may scratch your lenses.
  3. Store in a Case: When you are not wearing your glasses, store them for protection in a glasses case.
  4. Avoid Extreme Temperatures: High-index lenses will crackle under extreme temperatures. Do not leave your glasses in a hot car.

  5. Conclusion

    High-index lenses have enhanced our vision and our appearance. The days of bulky “coke-bottle” glasses are over. High-index lenses allow those with high glasses prescriptions to have thin, light lenses that improve the clarity of the world around us, improve our comfort, and enhance our natural facial features. They allow us to choose fun frames of different styles and materials that are compatible with high-index lenses. When you order your lenses from Overnight Glasses, you are recommended the thinnest lenses for your prescription. We will also upgrade any lens to aspheric design in order to make your lenses the thinnest possible.

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    Courtney Dryer, OD, is a 2011 graduate of SCO from Charlotte, NC. She's the owner of Autarchic Spec Shop. She... "Read More"