Handheld devices, such as smartphones and tablets, have unique patterns of use, viewing positions, sizes and text characteristics from their not-so-distant ancestor, the computer. Because of these variables in usage and the devices themselves, researchers have hypothesized that different digital device displays may also result in different dry eye symptoms.

A recent prospective clinical study examined the differences in ocular surface, tear film and visual fatigue parameters in individuals reading for 15 minutes on laptops, tablets, e-readers or smartphones. Participants included 31 healthy individuals between 20 and 26 years old. The researchers measured dry eye parameters at baseline, and then with and without artificial tear instillation before reading. Additionally, the participants took the Ocular Surface Disease Index (OSDI) and the Computer Vision Syndrome (CVS) questionnaires and underwent tear meniscus height, Schirmer’s, TBUT, osmolarity, bulbar redness and pupil size testing.

The researchers found statistically significant differences in OSDI and CVS questionnaire scores, tear meniscus height, Schirmer’s testing, TBUT, osmolarity and bulbar redness among the four different digital device displays. Post-task pupil size was not significantly different, and the researchers noted that any pupil response and change may be related to the level of visual fatigue experienced by the participants during viewing. Previous research suggests the possibility of pupil after-effects with near work.

The investigators noted that the best results were seen with smartphones and e-readers. Laptops caused the largest disturbance to the ocular surface and tear film. Instillation of artificial tears prior to screen reading resulted in no statistical improvement of ocular surface or tear film parameters for the same device.

The study authors concluded, “Taking into account the clinical test for dry eye diagnosis, the smartphone may be considered as the least disturbing display, producing lower dry eye symptoms and signs in comparison with other devices.”