Lens Guide--Materials & Treatments

ALDERMILLER OPTICAL

Chapter One

Polycarbonate

Refractive Index 1.586

  Impact Resistant       Lightweight       UV Protected 

Polycarbonate is the workhorse of modern optics — originally engineered for spacecraft windshields and riot shields. It is roughly ten times more impact-resistant than standard plastic, which is why it is the default choice for children's eyewear, safety glasses, and rimless frames where the lens edge bears the full mechanical load.

It is lighter than glass or standard CR-39 plastic, and it blocks 100% of UVA and UVB radiation without any additional UV coating. Its refractive index of 1.586 keeps lenses noticeably thinner than basic plastic at mild-to-moderate prescriptions.

The one trade-off worth knowing: polycarbonate is softer than high-index materials, so an anti-scratch coating is essential for longevity.

Children, active lifestyles, rimless or drill-mounted frames, mild-to-moderate prescriptions (up to approximately ±4.00)

Trivex

Refractive Index 1.530 — Abbe Value 45

  Sharpest Optics       Lightest Material       UV Protected 

Trivex is the premium alternative to polycarbonate for wearers who prioritize optical clarity above all else. It shares polycarbonate’s impact resistance and UV protection, but it has a substantially higher Abbe value — a measure of how cleanly a lens bends different wavelengths of light. A higher Abbe value means less chromatic aberration, which is that faint rainbow fringing at the edges of your vision that some polycarbonate wearers notice without realizing it.

Trivex is slightly less dense than polycarbonate, making it the lightest lens material we carry — a genuine advantage for full-time wearers. It is also easier to drill and edge, making it an excellent choice for rimless or three-piece frames where precision matters.

Because its index is slightly lower (1.530), Trivex lenses are marginally thicker than polycarbonate at higher prescriptions — generally not a visible difference below ±5.00.

Wearers with sharp peripheral vision needs, rimless frames, pilots, drivers, and anyone who notices edge distortion with standard polycarbonate

1.67 High-Index

Refractive Index 1.670

  Thinnest Profile       Strong Prescriptions       Aesthetically Slim 

High-index lenses are engineered for strong prescriptions. The number 1.67 refers to how efficiently the material bends light — the higher the index, the less material is needed to achieve the same optical correction. The practical result: a −6.00 prescription ground in 1.67 high-index produces a lens that is typically 30–40% thinner and lighter than the same prescription in standard polycarbonate.

This matters aesthetically. Strong minus prescriptions (nearsightedness) create thick edges; strong plus prescriptions (farsightedness) create thick centers. High-index material dramatically reduces both, allowing stronger prescriptions to sit comfortably in nearly any frame — including stylish narrow or semi-rimless designs that standard materials would make impractical.

Because high-index materials are denser and reflect more light than standard plastics, they almost always require an anti-reflective (AR) coating for comfortable wear. Without it, internal reflections can reduce contrast and create visible glare in the lens. We include AR coating as a recommended pairing with every 1.67 high-index order.

Prescriptions above ±4.00 sphere, fashion-forward frames with narrow or shallow lenses, wearers who have been told their lenses look thick, and progressive wearers with high prescriptions who want a slimmer profile

Chapter Two

Solid Tint

Sun & Style

A solid tint is a uniform color applied throughout the lens, giving it consistent density from edge to center. Unlike photochromic lenses, the tint is permanent and does not change with light conditions. We offer tints across the full visible spectrum — from classic grey and brown to fashion-forward rose, amber, green, and blue.

Grey tints are optically neutral — they reduce brightness without altering color perception, which is why they are favored for driving. Brown and amber tints enhance contrast and depth perception by filtering blue light selectively, making them popular for outdoor sports and overcast conditions. Fashion tints prioritize aesthetic expression and work well as sunwear when combined with UV coating.

Tint density is expressed as a percentage of light transmission. We offer light (15–35%), medium (50%), and dark (80%) options. All prescription tinted lenses from Aldermiller include UV protection.

Polarized

Glare Elimination

Polarized lenses contain a laminated filter — oriented horizontally inside the lens material — that blocks the specific wavelengths responsible for reflected glare. When sunlight bounces off a flat surface like wet pavement, a lake, or a car hood, it becomes polarized: the light waves align in a single horizontal plane. A polarized lens, oriented perpendicularly to that plane, cuts it selectively while allowing ambient light through.

The result is striking. Surfaces that would otherwise be washed out by glare become visible and detailed. Colors appear more saturated. Eyes experience less strain on long drives or days spent near water. Many wearers describe polarized vision as “seeing in high definition” outdoors.

There are contexts where polarization is less desirable: LCD screens (ATM pads, GPS displays, some car dashboards) can appear dimmed or disappear entirely when viewed at certain angles through a polarized lens. Skiers should also note that polarization can make it harder to distinguish icy patches on snow by reducing surface glare cues.

Anti-Reflective Coating

Clarity & Comfort

Anti-reflective (AR) coating — also called anti-glare or AR treatment — is arguably the single most impactful lens upgrade available. Standard lenses reflect approximately 8–10% of incoming light from their surfaces. AR coating reduces that figure to under 0.5%, meaning nearly all light that enters the lens reaches your eye rather than bouncing back as a reflection.

The immediate benefits are dual: you see more clearly, and others see your eyes more clearly. The ghost reflections that appear on uncoated lenses in photos — and in everyday conversation — nearly disappear. Night driving improves substantially, as halos and starburst patterns around oncoming headlights are a direct result of uncoated surface reflections.

AR coating is applied in multiple ultra-thin layers using a vacuum deposition process. Aldermiller’s AR coating includes a hydrophobic top layer that repels water, oils, and fingerprints, making lenses easier to clean and keeping them looking clearer throughout the day.

Blue-Light Filtering

Digital Eye Wellness

High-energy visible (HEV) blue light — emitted in concentrated form by smartphones, tablets, computer monitors, and LED lighting — falls between roughly 380 and 500 nanometers on the visible spectrum. It is the shortest-wavelength visible light, which means it scatters more inside the eye and may contribute to visual fatigue during extended screen use.

Blue-light filtering lenses selectively absorb or reflect a portion of this high-energy range — typically wavelengths below 450 nm — while transmitting the broader visible spectrum without significant color distortion. The result is a lens that reduces the most potentially disruptive portion of blue light without giving images a strong yellow cast.

Research on digital blue light and long-term retinal damage is ongoing. What is well established: blue light in the 460–480 nm range suppresses melatonin production, affecting sleep onset. Many wearers report reduced end-of-day eye fatigue and improved sleep quality after switching to blue-light filtering lenses for evening screen use.

Photochromic — Neochrome & GenX

Light-Adaptive Lenses

Photochromic lenses contain light-sensitive molecules — typically silver halides or organic photochromic dyes — that change their molecular structure when exposed to ultraviolet radiation. Outdoors in sunlight, the molecules darken the lens to sunglass density; indoors or at night, they return to near-clear within minutes. The wearer carries one pair of glasses and gets full optical correction in every light condition.

Aldermiller offers two photochromic technologies:

Neochrome — a premium photochromic platform that activates faster, clears faster, and maintains performance in a wider temperature range than first-generation transitions. Neochrome lenses darken to approximately 85% absorption outdoors and return to under 20% transmission indoors within 2–3 minutes.

GenX — designed specifically for polycarbonate and high-index substrates, GenX delivers reliable photochromic performance in thinner, lighter lenses. It offers a full dark-state comparable to Neochrome with excellent long-term durability.

Anti-Fatigue

Designed for Screens

Anti-fatigue lenses are a category of single-vision lens with a subtle, engineered boost in the lower portion of the lens — typically +0.60 to +0.85 diopters of additional plus power. This boost reduces the demand on the ciliary muscle, the ring of muscle inside the eye responsible for adjusting focus between distances. During prolonged near work — reading, typing, scrolling — this muscle works continuously at sustained contraction, which is a primary contributor to the eye strain, headaches, and blurred distance vision many people experience after long screen sessions.

Anti-fatigue lenses effectively give the ciliary muscle partial assistance during near tasks, reducing sustained effort without eliminating the flexibility to look up and focus at distance. Because the boost is confined to a small zone in the lower lens, it is virtually invisible — wearers adapt in hours, not weeks, unlike progressive lenses.

These lenses are appropriate for adults in their mid-twenties through mid-forties who are not yet presbyopic but spend four or more hours daily at a screen. They are not a replacement for progressive lenses in patients with diagnosed presbyopia, but they are a meaningful preventive tool for extended screen workers.

QUICK REFERENCE

Material Comparison at a Glance

For prescriptions referenced as sphere power only. Individual results vary by prescription type and frame choice.

Material	Index	Abbe Value	Impact Resistance	Weight	Best Rx Range	UV Block
Polycarbonate	1.586	30	Excellent	Light	Up to ±4.00	100%
Trivex	1.530	45	Excellent	Lightest	Up to ±5.00	100%
1.67 High-Index	1.670	32	Good	Moderate	±4.00 and above	100%

Not sure which combination is right for your prescription and lifestyle?

Our team reviews every order individually and will reach out with a recommendation before your lenses are fabricated.

Questions? Contact us at hello@aldermiller.com

This content is for educational purposes. It is not a substitute for professional eye care advice from a licensed optometrist or ophthalmologist.