Accommodative Stimulus-Response Curve with Emoji Symbols.

PURPOSE

To evaluate the static measurement of the accommodative stimulus-response curve with emoji symbols.

METHODS

The accommodative stimulus-response curve was measured in 18 subjects using a Hartmann-Shack sensor to obtain the objective accommodative response from the Zernike defocus term. Measurements were acquired at different accommodative demands, from 0 to 3 D with a step of 0.5 D. Detailed and nondetailed emoji targets were used with two different sizes, corresponding to the two most common visual angles used in smartphones.

RESULTS

A regression analysis was performed to fit the mean results obtained for each target. The determination coefficient was ≥ 0.988 for all targets. For the detailed targets, the slopes for the averaged stimulus-response curve were 0.65 and 0.66 for the bigger and smaller sizes, respectively. For the nondetailed targets, the slopes were 0.60 and 0.58 for the bigger and smaller sizes, respectively. values for these slopes were statistically significant for the two types of targets ( < 0.01).

CONCLUSIONS

Our results reveal that the replacement of a word or several words by detailed or nondetailed emoji symbols seems not to provoke a different accommodative response in normal subjects and under standard viewing conditions in the use of smartphones.