Glare-free desk lamps: UGR, reflections and how to choose

Where glare at a desk comes from

When you work at a screen, two kinds of stray light occur. Direct glare arises when a bright light source is in your field of view, for example an unshielded LED head at eye level. Reflected glare arises when light is mirrored on the screen or on glossy paper and comes back at you as a bright patch. Both effects show up as a loss of contrast: text is harder to read and your eyes have to work harder.

The starting point is therefore not the lamp but your workstation. Where does the monitor stand? Does daylight come from the side or from the front? Do you also work with paper, a notebook or a tablet? A lamp that is well placed over the keyboard may not disturb a matt monitor, yet can still cause reflections on a glossy display. For the basics of lighting at a workstation, see our guide to working in an eye-friendly way.

This page is based on manufacturer and listing information as well as standards. We have not measured anything, and we did not have the lamps mentioned in use, so no hands-on testing is documented. Statements about glare-free operation are therefore always manufacturer claims and not our own finding.

A simple self-check beforehand: sit in your normal working posture, switch the screen to dark and look at which bright surfaces are reflected in the display. These reflections show you which direction stray light comes from, and therefore where a new lamp must not stand.

What UGR tells you and what it does not

UGR stands for Unified Glare Rating. It is calculated for interiors, from the arrangement and luminance of all luminaires, the room and the viewing direction. According to BS EN 12464-1 (Light and lighting, lighting of indoor workplaces), the limit for office workstations with a screen is UGR 19. The standard applies to the lighting design of a room and does not rate an individual desk lamp.

This has a practical consequence. If a listing advertises a UGR value for a desk lamp, that is not a standardised property of the lamp but at best a manufacturer's calculation under certain assumptions. None of the five product pages compared here states a UGR value. Instead, the sources name the optic, shielding and light distribution. For everyday use that is also more meaningful: you can check whether the light source is in your field of view, and that is exactly the question UGR answers in room planning.

For brightness, the same standard gives a guide value of 500 lux for office work. How much luminous flux is needed for that depends on the distance and the area. The article on lumens for a desk lamp offers a calculation aid, and the lighting calculator helps you assess your room.

A rule of thumb that needs no numbers can be derived from this. The smaller and brighter the visible light surface is relative to its surroundings, the more likely glare is. A wide, shielded light bar above the monitor creates different conditions from a small lamp head on an adjustable arm that stands close to your line of sight. The standard gives you no test value for the desk lamp, but the logic behind it stays the same: brightness belongs on the work surface, not in your eye.

Asymmetric light: how monitor light bars avoid reflections

A monitor light bar sits on the top edge of the screen. Its optic is shaped so that the light falls forwards and downwards onto the keyboard and desk surface and only a little onto the display. Manufacturers call this asymmetric light distribution. Because the LEDs are shielded from below, the light source sits outside your field of view as long as you look straight at the monitor.

According to the manufacturer, BenQ follows this principle across several models. The listing for the BenQ ScreenBar mentions Asym-Light, which is meant to prevent screen reflections and direct glare. For the BenQ ScreenBar Halo 2 the listing gives an anti-glare angle of 18 degrees, and for the BenQ ScreenBar Pro a third-generation Asym-Light optic. Whether the effect occurs on your monitor depends on the screen. Glossy displays and windows behind you can still cause reflections, and no lamp optic alone can prevent that.

Flicker is also part of the glare question. Visible or subliminal flicker strains the eyes regardless of brightness. The ScreenBar listing mentions a flicker-free light source, and the Quntis lamp listing says no flickering. Both are manufacturer claims without a measured value. What to check when a light flickers is explained in the article LED flickers.

Height is part of the setup too. If the lamp sits too far forward on the monitor frame, light falls at an angle onto the display; if it sits too far back, the front area of the desk stays dark. According to the listings, the mounts of the models mentioned are designed for certain monitor thicknesses, so it is worth checking the details before you order. For monitors with a webcam at the top edge, also make sure the lamp body does not cover the camera. According to the manufacturer, the Halo 2 is explicitly designed not to cover webcams.

Five monitor light bars in a data comparison

The following table contains only details that appear on the respective product pages. Where nothing is stated there, it says "not stated". All values come from the manufacturers or from the retailer listings, and we have not re-measured them.

The table mainly shows how uneven the sources are. For the BenQ models, the listing gives light distribution and brightness ranges; for the Xiaomi light bar it gives colour temperature, controls and connection. A statement about glare-free operation therefore cannot be derived from the documents for the Xiaomi lamp.

Which design suits you, if

One screen, little desk space

A monitor light bar saves floor space on the desk and lights the front area of the desk. According to the manufacturer, the BenQ ScreenBar has a clamp for monitors 1 to 3 cm thick, including curved models from 1,500R. That suits you if your monitor has a normal back. The listing notes that a special monitor back design can affect compatibility.

Wide or curved monitor

According to the manufacturer, the BenQ ScreenBar Pro covers monitors from 0.43 to 6.5 cm thick and a curvature of 1,000 to 1,800R, as well as lighting over 85 x 50 cm. It is the alternative to the ScreenBar if the space is to be lit more widely or the monitor is thicker.

Dark room and long sessions

According to the manufacturer, the BenQ ScreenBar Halo 2 comes with a wide, adjustable backlight that is meant to reduce the contrast between a bright display and a dark surrounding. That suits you if you work in the evening in an otherwise unlit room. According to the listing, the clamp is designed for monitor thicknesses of 0.43 to 6 cm.

Remote control and auto-dimming

The Quntis Monitor Light Bar 41 cm is an alternative to the BenQ models if a remote control and auto-dimming are enough. According to the listing, it is powered via a 2 m USB-C cable at 5 V. According to the listing, the colour temperature can be set between 3,000 and 6,500 K. A price comparison does not belong on this page; the respective product page places the price band.

A classic desk lamp with an adjustable arm remains an option if you work a lot with paper. However, it needs desk space and is easier to position so that it causes glare. The trade-off against the monitor light bar is covered in the article Are monitor light bars worth it?.

Colour temperature, sensors and health note

Colour temperature is given in kelvin. Warm light around 2,700 K feels more relaxed, while neutral to cool light up to 6,500 K is considered more stimulating. You can find the explanation in the article on colour temperature in kelvin. For the evening, a lamp that can be set down into the warm range is practical. According to the manufacturer, the range of 2,700 to 6,500 K covers this for the ScreenBar and the Halo 2.

Auto-dimming and the motion sensor are convenience features. According to the manufacturer, the light sensor adjusts the brightness to the ambient light. According to the listing, the sensor of the ScreenBar Pro switches the lamp off after 5 minutes when you leave your seat. If you often read leaning back, combine the automatic mode with manual control so that the lamp does not switch off unexpectedly.

Health note: Good workplace lighting can reduce discomfort caused by glare. It does not replace medical treatment. If you have persistent eye discomfort, headaches or changes in your vision, see an eye specialist.

A further note on colour temperature, from planning practice: the colour temperature of the lamp should suit its surroundings. A very cold work light next to warmly lit walls stands out as a jump in colour, and many people find that unsettling. So first set the lamp close to the colour of your room lighting and change it in small steps.

Checklist for choosing

The following points help with choosing, whatever the model.

• Check where the light falls. It should hit the keyboard and paper, not the display.
• Check the monitor thickness and curvature against the details of the mount.
• Look at whether brightness and colour temperature can be set separately. That says more than a single maximum value.
• Set the brightness so that the screen does not look much darker than its surroundings.
• Do not trust a UGR value in the listing of a desk lamp without knowing the assumptions and the test standard.

If you are planning the whole workstation, the overview of desk lamps helps, with further designs listed there. You can enter room, daylight and screen size in the lighting calculator. The lamps mentioned at a glance: BenQ ScreenBar, BenQ ScreenBar Pro, BenQ ScreenBar Halo 2, Quntis Monitor Light Bar 41 cm and Xiaomi Mi Computer Monitor Light Bar.