Measurement of Retinal Sensitivity on Tablet Devices in Age-Related Macular Degeneration

Abstract

Purpose: We compared measurements of central retinal sensitivity on a portable, low-cost tablet device to the established method of microperimetry in age-related macular degeneration (AMD).

Methods: A customized test designed to measure central retinal sensitivity (within the central 1° radius) on a tablet device was developed using an open-source platform called PsyPad. A total of 30 participants with AMD were included in this study, and all participants performed a practice test on PsyPad, followed by four tests of one eye and one test of the other eye. Participants then underwent standardized microperimetry examinations in both eyes.

Results: The average test duration on PsyPad was 53.9 ± 7.5 seconds, and no significant learning effect was observed over the examinations performed (P = 1.000). The coefficient of repeatability of central retinal sensitivity between the first two examinations on PsyPad was ±1.76 dB. The mean central retinal sensitivity was not significantly different between PsyPad (25.7 ± 0.4 dB) and microperimetry (26.1 ± 0.4 dB, P = 0.094), and the 95% limits of agreement between the two measures were between -4.12 and 4.92 dB.

Conclusions: The measurements of central retinal sensitivity can be performed effectively using a tablet device, displaying reasonably good agreement with those obtained using the established method of microperimetry.

Translational relevance: These findings highlight the potential of tablet devices as low-cost and portable tools for developing and performing visual function measures that can be easily and widely implemented.

Keywords: age-related macular degeneration; iPad; microperimetry; visual function.

Figure 1

Illustration of the customized test designed on the PsyPad platform to measure central retinal sensitivity (within the central 1° radius) and the location of the five test stimuli are shown. The test stimuli are presented within the fixation target (red ring, 3° in radius) and participants responded to seeing a stimulus by pressing the grey response square at the bottom right hand corner.

Figure 2

Customized grid on microperimetry with the fixation target represented by the red ring and central retinal sensitivity defined as the average of the five points (lighter grey points) within the central 1° radius.

Figure 3

Intrasession changes in mean central retinal sensitivity using PsyPad for participants with AMD, showing no significant differences in the mean central retinal sensitivity between any pair of the four sequential examinations in both groups. Error bars: 95% CI of the mean.

Figure 4

Bland-Altman plot of mean central retinal sensitivity measurements obtained using PsyPad and microperimetry, illustrating the agreement between the two measures (the difference was obtained by subtracting the central retinal sensitivity results of microperimetry from PsyPad). Horizontal dashed lines represent the upper limits of 95% of the mean (+2 SD), mean, and lower limits of 95% of the mean (−2 SD) from top to bottom respectively, and the solid dashed line represents zero.