Optimal lighting for individuals with vision loss can vary significantly. While many with low vision find increased illumination beneficial, some visually impaired individuals are light-sensitive and may function better in lower light conditions.
Sunlight is a natural light source that has the full spectrum of wavelengths. Most with low vision find that natural lighting is the best for their visual functioning, while some with low vision are light-sensitive and find sunlight too harsh.
How to Optimize Lighting for the Visually Impaired
The goal of managing lighting for low vision is to optimize visual function. The correct amount of light is a balance between:
- ambient room lighting,
- direction and brightness of additional light sources,
- the task to be performed, and
- the degree (or type) of vision loss, along with personal preferences.
Ways to Optimize the Lighting in the Home
Start with:
- change to higher luminance light bulbs for room lighting,
- bring task lighting sources close to the work area,
- reduce glare, and
- increase contrast.
How to Optimize Ambient Room Lighting
Enhancing the brightness of light bulbs in overhead ceiling fixtures is crucial, particularly in areas like hallways, closets, and kitchens.
Moreover, for overhead lighting, consider installing dimmer switches to provide better control over room illumination. This adjustment is especially beneficial for individuals sensitive to bright light.
Finding light switches in the evening or at night can pose challenges for those with impaired vision. To address this, think about integrating light sources with voice-activated personal assistants such as Apple’s Siri, Amazon’s Alexa, or Google Assistant. This solution requires WiFi connectivity along with smart plugs or bulbs. Smart bulbs offer the advantage of adjusting brightness and color temperature, though setting up a smart bulb system can be pricier and more complex.
For rooms that receive ample sunlight, adjustable window shades are recommended to regulate room lighting.
How to Optimize Light in Work Areas
When engaging in tasks such as reading, hobbies, or detailed work, it’s beneficial to use directional lighting. Over-the-shoulder lights should be positioned on the opposite side of the individual’s dominant hand. Typically, this is the hand holding the pen or magnifier, ensuring that the body does not cast a shadow on the reading material.
Directional lamps should be equipped with shades and positioned to direct light towards the reading material or work surface. The shade helps prevent glare and keeps the light from shining directly into the eyes.
Remember, the closer the light source, the better the illumination. Enhance brightness by bringing the light source closer to the task at hand.
Reduce Glare to Optimize Visual Function
Glare significantly reduces the ability to ‘see’ clearly, leading to discomfort and eye fatigue. There are two main types of glare: discomfort glare and disabling glare.
Discomfort glare occurs when light reflects and scatters off surfaces, interfering with the light illuminating the task or object at hand, making it harder to see.
Disabling glare, on the other hand, is caused by excessively bright lighting. When illumination is too high, it can result in discomfort and eye fatigue. People without eye conditions often experience this when sunlight reflects off surfaces like sand or snow on bright days. Similarly, individuals with low vision may find themselves affected by bright lighting in a room.
To mitigate glare, consider adjustable window shades that can reduce incoming sunlight while still allowing for natural light enjoyment.
For close directional lighting on paper or work surfaces, adjust the lamp if it is a ‘gooseneck’ type, enabling the direction of light to be changed to minimize glare off the work surface.
Avoid using white, shiny, glass, or metallic counters, tables, and desks. Opt instead for darker or matte-finished surfaces, or coverings that absorb light rather than reflect it. In rooms where overhead lighting causes visual fatigue and discomfort, wearing a hat or visor can also help.
How to Increase Contrast to Optimize Visual Function
Contrast sensitivity refers to the ability to distinguish an object from its background. For instance, placing silver coins on a shiny metallic counter creates low contrast (grey on grey). While the average sighted person may have no trouble seeing the coins, someone with low contrast sensitivity might not notice them. On the other hand, placing silver coins on a matte white counter increases the contrast significantly. This makes it easier for someone with low contrast sensitivity to detect the coins against the white surface.
Various environmental changes can improve contrast sensitivity, such as altering the color of tables and countertops, avoiding busy patterns, incorporating colorful markings, and adjusting lighting.
Enhance object contrast by using lights under counters, illuminated mirrors, directional lighting for appliance controls, and over-the-shoulder lighting in reading areas. It’s important for overhead lighting to be sufficiently bright to fill the room, eliminating dim or shadowy areas with low contrast.
What Makes Someone More Light-sensitive?
The ideal lighting for individuals with low vision can vary depending on the type of eye disease they have. Conditions such as ocular albinism, achromatopsia, or retinitis pigmentosa often result in heightened light sensitivity compared to conditions like cataracts, macular degeneration, or diabetic retinopathy.
Damage to the retina can lead to difficulties in adjusting to varying light levels. For instance, being confronted with bright headlights from an oncoming car at night or transitioning from a well-lit room to a dark hallway can be challenging for those with light sensitivity, causing them to feel ‘dazzled’ by the abrupt change in light levels. The inability to adapt to these significant light level shifts poses a problem for individuals with visual disabilities.
Interestingly, there is currently no in-office technology available to objectively measure an individual’s level of light sensitivity. It largely remains a subjective assessment. Therefore, if you experience light sensitivity issues, it’s important to communicate this to your eye care practitioner. Those who provide care for the visually impaired should proactively inquire about any concerns regarding lighting.
The suggestions for patients who are light-sensitive are not to decrease light completely, but to ensure that light is adjustable for how they are feeling or what they need to ‘see.’ The suggestions made above for ambient room light levels and controlling glare, apply especially to those who are light-sensitive.
- Adjustable window shades,
- dimmable overhead lighting, and
- adjustable task lighting.
Those who are light-sensitive may also benefit from tinted lenses. Tinted lenses will not increase visual acuity or visual function, but can make the light sensitive more comfortable and better able to adjust to different light levels.
A company known for offering tinted lenses for low vision is NOIR
.
What are the Best Types of Lights
There are several types of lights commonly found in homes and offices: incandescent, fluorescent, CFL (Compact Fluorescent Lamp), halogen, and LED (Light-Emitting Diode). In the United States, most incandescent and halogen bulbs are being phased out by August 2023 due to their high energy consumption.
For the purposes of this discussion, I will focus on the two most commonly used types: fluorescent and LED.
LED bulbs are increasingly replacing incandescent bulbs in homes. They offer significant energy savings and have a longer lifespan.
What to look for when purchasing lights for the Home
The two most useful numbers on the box are lumens and light appearance. Lumens indicate brightness. The higher the lumen number, the higher the brightness. Lumen values are between 250 L and 5800 L. After living with incandescent for many years, we are more familiar with ‘watts.’ So here is a comparison.
| Incandescent Watts | 25 W | 40 W | 60 W | 75 W | 100 W | 150 W | 300 W |
| LED Lumens | 200 L + | 400 L + | 700 L + | 1100 L + | 1600 L | 2000 L + | 5000 L |
The other factor to consider is Color Temperature or light appearance. Manufacturers have been able to adjust the ‘color temperature.’ This is indicated as ‘K’ (Kelvin.) More likely it will appear on the box as:
Warm (Soft) White (1900 t0 3200 K),
Neutral White (3500K),
Cool White (4000K), or
Daylight (5000K).
By comparison, incandescent light is in the Warm whites, 2300 to 2850 K. In the home, we are more comfortable with the warm cast of the incandescent bulb and should choose warm white LEDs. The Cool White is the blue cast which is usually undesirable.
For example: if you like the warmth of the incandescent, but need bright light, you would look for an LED with something like “Warm (or Soft) White, 2700K, Bright 2600L, 150 Watt equivalent.”
Another factor to consider, for those who need true and natural colors like artists, is the CRI (Color Rendering Index.) The index is 0 to 100. 0 indicates no color distinction, all colors will look neutral. A CRI of 100 indicates natural color rendering. Incandescent bulbs have a CRI of 100. For the most part, LEDs are 80 – 85, with a few rare exceptions.
The last consideration is: Will the bulb be used in a fixture with a dimmer for adjusting light levels? Not all bulbs are ‘dimmable.’ So check for this option.
Fluorescent Lights: One of the most common complaints about fluorescent lighting is its color rendering and tendency to flicker.
Fluorescent lights have long been favored for commercial buildings due to their broad, bright illumination and cost-effectiveness. However, the light they emit can sometimes feel harsh and distort colors, particularly with Cool White variants which have a low Color Rendering Index (CRI) of 50-60.
In addition to the standard commercial fluorescent lighting, there are various types available with improved color rendering. These differences are based on the phosphors used in the bulbs.
Both CFLs (Compact Fluorescent Lamps) and tube-type fluorescent bulbs are available in different color temperatures. For home use, consider opting for Soft (or warm) White for a more comfortable ambiance. If you prioritize high CRI (80-90) for accurate colors, Daylight fluorescent bulbs are a better choice as their spectrum closely resembles natural light.
Older or budget fluorescent fixtures may exhibit a strobe-like effect that can lead to eye fatigue. This flickering can be alleviated by installing high-frequency electronic ballasts, which prevent flickering compared to older magnetic types.
When selecting fluorescent bulbs, check if they are dimmable. Dimmable fluorescent lights require a compatible dimmable ballast to work with a dimmer switch for adjusting light levels.
Learn about other workplace modifications for the visually Impaired: How Do Visually Impaired People Work?
In the End…
Often, individuals with low vision, as well as those who care for them, may underestimate the impact that proper lighting can have on their visual abilities.
Boosting light levels can significantly improve visual acuity, contrast sensitivity, and color perception, but there is a limit to its effectiveness. The optimal amount of light varies from person to person. However, in most cases, making lighting modifications can greatly enhance visual function.
You must be logged in to post a comment.