The Jiangsu Consumer Association organized a comparative test on 173 batches of reading and writing table lamps on May 16. The samples were purchased from physical shopping malls and online stores (Tmall, JD.com and Suning.com). The testing covered five technical indicators: power cord length, light

The Jiangsu Consumer Association organized a comparative test on 173 batches of reading and writing table lamps on May 16. The samples were purchased from physical shopping malls and online stores (Tmall, JD.com and Suning.com). The testing covered five technical indicators: power cord length, light shielding performance, color temperature, color rendering index and photometric requirements.

The test results showed that only 3 batches met all five technical indicators, and 98% of the tested samples failed to satisfy one or more technical standards; over 80% of the table lamps had excessively high color temperature, which may harm eyesight.

▼ Types and Quantities of Light Sources in 173 Batches of Samples

Test Background: The proportion of primary and secondary school students in Jiangsu Province suffering from declining eyesight and myopia has been on the rise. To better provide consumption guidance for consumers, guide them to properly select table lamps for children’s reading and homework and protect the eyesight of students, especially primary and secondary school students, the Jiangsu Consumer Association carried out this comparative test of reading and writing table lamps in accordance with its duties prescribed by the Consumer Rights Protection Law of the People's Republic of China.

Over 80% of Tested Table Lamps Have Excessively High Color Temperature

The test results of the 173 batches of samples revealed that merely 38 batches featured power cords reaching 1.8 meters, meaning more than 80% failed this standard. 84 batches of table lamps failed to reach Class A central illuminance (250 lx), among which 20 batches did not even hit 100 lx for central illuminance, accounting for nearly half of the non-compliant samples.

Relevant standards stipulate that the color rendering index of light sources for reading and writing table lamps shall not be lower than 80. In this test, 71 batches of table lamps failed to meet the Ra color rendering index requirement. A light source with an excessively low color rendering index cannot reproduce the true colors of objects, greatly reduces visual comfort and easily induces visual fatigue.

The color temperature benchmark adopted in this table lamp test was 4000K. Only 30 batches of table lamps had a color temperature below 4000K, which indicates that over 80% of the lamps had overly high color temperature. In addition, 21 batches of table lamps in this comparative test had a color temperature exceeding 6500K, and one LED table lamp even reached an extremely high color temperature of 11643K.

The color characteristics of light emitted by a light source are determined by correlated color temperature and color rendering index. Relevant standards suggest that the correlated color temperature of reading and writing table lamps should not exceed 4000K, mainly due to blue light’s impact on the circadian rhythm. Blue light has a wavelength of approximately 450nm, which is closely linked to the human body’s day-night cycle, and it strongly inhibits the secretion of melatonin.

If a light source has an excessively high color temperature above 5500K, most of its spectral energy concentrates in the 460nm band, which aligns with the waveform of the human circadian rhythm curve. This disrupts the body’s normal immune mechanisms, makes people overexcited and unable to fall asleep. Long-term exposure will further impair immune function. Primary and secondary school students, who are in a critical period of physical growth and development, face higher risks of visual damage. Therefore, teenagers should avoid using high-color-temperature LED table lamps at night.

Common Consumer Misconceptions

Many products on the market are labeled "eye-protective table lamps", leading consumers to mistake this product name for a functional certification. In fact, "eye-protective lamp" is merely a common term. No specific national standards have been formulated for the eye-protection performance of reading and writing table lamps, and rigorous research has not verified the correlation between eye protection and table lamp performance.

Another major selling point of mainstream eye-protective table lamps on the market is "flicker-free". The basic working principle of most such lamps is to raise the oscillation frequency of ordinary fluorescent lamps from low-frequency flicker to high-frequency flicker, rendering flicker invisible to the naked eye. However, long-term close use of high-frequency lighting fixtures may harm health.

Many consumers judge table lamps by "high brightness" when making purchases. Unknown to them, while greatly boosting illuminance, higher lamp brightness also intensifies harmful reflective glare. This damages the cornea, inhibits the function of retinal photoreceptors and causes visual fatigue.

Furthermore, LED lighting, an emerging type of lamp, is popular among consumers for its high luminous efficiency and long service life, creating a false impression that all LED lamps are high-end and high-quality. Most white LED lamps on the market tend to produce direct glare. Without anti-glare measures such as optimized light-emitting angles, grids or lenses, they emit harsh light unsuitable for reading.

Guidelines for Properly Purchasing Healthy Lighting Products

Yiguang Technology reminds consumers to buy table lamps through official channels, inspect product labels and markings, and pay attention to key performance parameters including color temperature, color rendering index, light uniformity and anti-glare performance.

Among existing light sources, candlelight has a color temperature of roughly 2000K, incandescent lamps range from 2700K to 3000K, morning sunlight stands at around 4400K, and midday sunlight rises to 5600K. It is ideal for people to use light matching natural light cycles at different times of day. Nevertheless, most LED lamps available now have excessively high color temperature. Long-term use interferes with the human biological clock, disrupts sleep and circadian rhythms, and weakens immunity. OLED light sources, with a color temperature ranging from 3000K to 4000K, are currently the more ideal option. Thus, consumers should avoid table lamps with a color temperature above 4000K when shopping.

Color rendering performance is a core indicator of lighting quality. Most indoor lighting standards require a color rendering index of no less than 80. Sunlight has a color rendering index of 100; incandescent lamps come closest to sunlight, followed by OLED light sources (above 90), while LED lamps generally score between 70 and 80 on the color rendering index scale. To improve definition and color authenticity during work and relieve eye strain, consumers should select lamps with a color rendering index (Ra) of at least 80. For tasks requiring high color accuracy such as painting and color matching under table lamps, choose lamps with a color rendering index of no less than 90.

Regarding glare and light uniformity, diffuse flat panel light sources (OLED) are recommended over concentrated point light sources. Uniform light eliminates glare and effectively alleviates visual fatigue.

(Content reference: China Consumer News · China Consumer Network)

Appendix: The main reference standards for this comparative test include GB/T 9473-2008 Performance Requirements for Reading and Writing Table Lamps, GB 50034-2013 Standard for Lighting Design of Buildings, GB/T 31831-2015 Technical Requirements for Indoor LED Lighting Applications, relevant clauses of CQC1601-2013 Technical Specifications for Visual Task Table Lamps issued by China Quality Certification Center, and the test was carried out in accordance with GB/T 16759-2008 General Rules for Comparative Testing of Consumer Goods and Related Services.