Assessing the resilience of portable vision tests to an uncontrolled home environment

In ophthalmology (and medicine more widely) there is increasing interest in telemedicine: having patients perform tests at home for greater efficiency and to meet growing demand. However, despite this increased interest in vision home monitoring, many vision tests are evaluated in standardised clinical settings, not home environments. Here, we investigated the resilience of two portable contrast sensitivity tests to the sorts of potentially confounding factors that may be encountered in a home setting.

Normally sighted adults (n = 107) performed two contrast sensitivity tests (one pen-and-paper and one tablet-based). Testing took place in a furnished apartment, where we could control/measure various extraneous factors (including illumination, time of day, seating type, screen cleanliness). Key outcome measures were raw contrast sensitivity scores, test-retest repeatability, and test duration; and how these metrics varied with extraneous factors.

No effect of time of day, participant motivation, or seating type was observed (all P_Bonferroni > 0.140). Scores on the pen-and-paper test were not affected by illumination (P_Bonferroni = 0.348), except when tests were conducted in extreme darkness (≤1 lux; P_Bonferroni = 0.036). A follow-up study indicated that screen smudging (caused by fingerprints) had no significant effect on the outcome of the tablet-based test (P = 0.573).

Taken together, the results indicate that, contrary to our expectations, both digital and pen-and-paper contrast sensitivity tests appear relatively resilient to many of the sorts of extraneous factors encountered in a home setting. This speaks to the potential viability of vision home monitoring, though study limitations and necessary future work are discussed.