The Consequences of Forgoing Anti-Reflective Coatings on 1.67 High Index Lenses
While 1.74 and 1.67 high index lenses can be on the pricey side, few can dispute the attractiveness of their thin and lightweight design. However, if you’re tempted to defray the cost by forgoing an anti-reflective coating, there are a number of aesthetic, safety, comfort, and eye health consequences you should consider first.
Before getting into this, note that all of these consequences stem from the fact that high index lenses reflect more light than lenses with a lower index number. It is this high reflectivity that leads to the listed problems below:
Light Reflection Prevents Others from Seeing Your Eyes
Eye contact is important in social and work environments. The eyes communicate important nonverbal information, which is obscured by external light reflections off the outside of your lenses. Seeing window glare off your glasses instead of your eyes, distracts from and gets in the way of this communication. This can affect the outcomes of important meetings, interviews, and first dates.
On the issue of dating, the eyes are the most attractive features of the face. The eyes are essential for expressing emotions such as laughter. They also reveal the difference between a forced and genuine smile. To connect with people and gain trust, they must know you as a genuine person, which is revealed by your eyes.
Light Reflection from Your Lenses Impedes Your Vision
Internal light reflection within the lens and off the inside and outside lens surfaces is called glare. Glare gets in the way of seeing your environment. This can cause injuries from falls, particularly when you’re rushed.
High index lens glare gets in the way of safe driving, especially at night. Light from oncoming traffic can cause star-burst glare when reflecting off your glasses. The light from traffic behind you and overhead street lamps can reflect back into your eyes from the inside surface of your lenses. These types of glare are distracting and interfere with your night vision. When combined with windshield and water streaking glare, the result is often overwhelming.
Light reflection from your glasses means less light passes through to your eyes. When night driving, this means your high index lenses are blocking much-needed light. This darkens your view of the road, much like a pair of sunglasses.
Glare Causes Discomfort, Headaches, and Fatigue
Glare causes the facial muscles around the eyes to tense. After several hours of this, discomfort and possibly headaches will set in. This constant stress and discomfort will add to your general sense of fatigue. Fatigue saps your energy levels, making you less productive at work, and less socially engaging.
This often happens to people who spend hours working with computers. Glare from external light sources such as overly bright lighting, open windows within your line of sight, and glare reflecting back at your eyes from the inside lens surface of your glasses, causes discomfort and eyestrain.
Light Reflection from Your Lenses Increases UV Exposure
High index lenses block between 60 and 80 percent of ultraviolet (UV) light. This figure is approximate and will vary depending on the specific lens material used. While blocking UV light is a good thing, UV can also enter the eyes when it reflects off the inside surface of your lenses. If you spend any time outdoors, sunlight (and its UV component) coming from above and behind you can enter your eyes via reflection.
Ultraviolet light is highly energetic and will damage the eyes over time. This damage is cumulative and may eventually cause eye problems such as cataracts later in life.
As you can see, there’s little sense to spending money on 1.74 and 1.67 high index lenses if it means suffering from the above consequences of not getting an anti-reflective coating. This is why anti-reflective coatings are part and parcel with high index lenses.