The specs that matter
Colour temperature
4000–5000K daytime / 2700–3000K evening
Measured in Kelvin. Warmer light (2700K) looks orange-yellow. Cooler light (6000K) looks blue-white. For daytime work, 4000–5000K is close to natural daylight and supports focus without the harshness of very cool bulbs. In the evenings, 2700–3000K reduces blue light exposure before sleep. A lamp with adjustable colour temperature handles both.
CRI (Colour Rendering Index)
90 or above
CRI measures how accurately a light renders colours compared to natural sunlight. Below 80, colours appear slightly flat or off — the visual system works harder to process what it's seeing over hours of work. CRI 90+ lamps show colours naturally and are noticeably more comfortable for extended sessions. Cheap LEDs often have CRI in the 70s.
Flicker
Flicker-free
Some lamps flicker at frequencies the eye perceives subconsciously without consciously registering the flash. This sustained neural load causes headaches and fatigue in sensitive people. Look for lamps that explicitly state 'flicker-free' output. Most quality LEDs qualify; cheap lamps often don't.
Brightness
Adjustable, matched to screen
Your lamp and your screen should be roughly similar in brightness. A desk lamp much brighter than the screen (or much dimmer, with the screen being the main light source) forces constant pupil adaptation that adds to fatigue over the day.
Where to position it
Position matters as much as the lamp itself. The goal is to illuminate your work surface without shining directly into your eyes or creating glare on your screen.
✓Place it to the side of your monitor, not directly behind or in front
✓Angle it so the light source is not directly visible in your peripheral vision
✓Don't position it behind your monitor pointing toward you — this creates the glare you're trying to prevent
✓For right-handed writers working on paper, light from the left prevents your hand from casting shadows
What doesn't matter much
Wattage is largely irrelevant for LEDs — it measures energy consumption, not light quality or comfort. Many lamps marketed specifically as "eye-friendly" or "eye-care" provide no CRI or flicker specifications, which means the marketing claims are unsupported.
Price is not a reliable proxy for quality in desk lamps. Expensive brands don't automatically mean better specs. Check the CRI rating and colour temperature range on the specific model, regardless of price.