Effects on the Ocular Surface from Reading on OLED vs Eink

Jjordan · 20 Jan

I wanted to share this. Looks like OLED displays mess up the ocular surface, decreases tear film stability. Eink shows to be a way healthier screen. (Which is obvious I know)

Here's a summary that I let ai generate from this link about the findings. (To spare my eyes)

https://pmc.ncbi.nlm.nih.gov/articles/PMC8212737/

Study Design: The study involved 119 volunteers randomly assigned to one of four groups:

1. Light environment + OLED screen

2. Light environment + eINK screen

3. Dark environment + OLED screen

4. Dark environment + eINK screen

Participants engaged in a 2-hour continuous reading session on their assigned screens. Ocular surface assessments—including noninvasive break-up time (NIBUT), noninvasive keratograph tear meniscus height (NIKTMH), ocular redness, fluorescein break-up time (FBUT), corneal fluorescein staining, meibomian gland assessment, Schirmer I Test, and blinking frequency—were conducted before and after the reading task. Symptoms were evaluated using the Ocular Surface Disease Index (OSDI) and Computer Vision Syndrome Questionnaire (CVS-Q).

Key Findings:

Tear Film Stability: Significant reductions in NIBUT and FBUT were observed after 2 hours of reading on OLED screens in both light and dark environments, indicating decreased tear film stability. In contrast, eINK screens did not show a significant impact on these measures.

Tear Volume: NIKTMH decreased significantly after reading on OLED screens under both lighting conditions, suggesting reduced tear volume. The eINK screens had a lesser effect on NIKTMH.

Ocular Redness and Discomfort: Increases in ocular redness and higher scores on the OSDI and CVS-Q were noted after reading on OLED screens, indicating greater subjective discomfort. The eINK screens resulted in fewer adverse effects on these indicators.

Blink Rate: Participants using OLED screens exhibited a gradual increase in blink rate during the reading task, possibly as a compensatory response to ocular surface stress. No significant change in blink rate was observed in the eINK groups.

Conclusion: The study suggests that reading on OLED smartphone screens can cause ocular surface disorders and subjective discomfort, whereas eINK screens may minimize these adverse effects in both dark and light environments. Optimizing smartphone screen technology, such as adopting eINK displays, could be beneficial for ocular surface protection, especially for individuals who use smartphones extensively or have pre-existing dry eye conditions.

photon78s · 20 Jan

Just referencing from the study:

Flicker refers to low VDT data refreshing rates below critical fusion frequency, the image on an OLED screen is not fixed, but refreshes at 60–90 Hz, which causes the brain to produce temporary vision and discern the screen as stable. In fact, the eyes can still feel the flicker, which easily generates visual fatigue. Conversely, the image on an eINK screen is fixed; thus, what the human eye sees is a real and stable picture without flicker. Another important reason for subjective discomfort is that because the wavelength of blue light is short, its focal point cannot fall on the retina, but instead falls a little in front of the retina, and the distance between the focal points in the eye is the main reason for the blurring of vision. In order to see the image clearly, it is necessary for the lens in the eye to adjust, which causes the eye muscles to remain in a state of tension for a long time, resulting in visual fatigue. The eINK screen does not emit light, so it does not produce blue light‐induced blurred vision and visual fatigue.