Clinically Unsupervised Visual Acuity Test Fails to Yield Reliable Measurements

A clinically unsupervised visual acuity test, administered by caretakers using a tablet, may yield measurements that are not in agreement with clinically obtained measurements and may not be suitable for determining visual acuity in children, according to an investigation published in Eye.

Researchers included 42 children (40.5 % girls; mean age, 5.58 years) who underwent visual acuity measurements 3 times during 1 appointment. A clinician performed the first 2 tests — the first was performed according to clinical protocols, while the second was administered using the tablet-based visual acuity test. Caretakers performed the third test using the tablet after receiving instructions on how to use the device.

Median visual acuity measurements were 0.155, 0.180, and 0.300 logarithm of the minimum angle of resolution (logMAR) using the clinical protocols, clinician-administered tablet test, and caretaker-administered, clinically unsupervised visual acuity test, respectively, revealing statistically significant differences between the 3 tests (P =.03). Direct comparisons of the tests revealed statistically significantly differences in measurements obtained by the caretakers vs the clinician using clinical protocols (P =.008), but no significant differences between measurements obtained by the clinician using the tablet-based test or clinical protocols (P =.108). 

“Our data suggests that while some parents/carers can test their children’s visual acuity using a clinic-like app, some may struggle,” according to the study authors. “Erroneous measures may not always be possible to detect and as such we do not think these tests should be used without supervision from a professional, and with limited training only.”

Study limitations include potential differences between conditions present in the testing clinic and participants’ homes and the non randomized order of the visual acuity tests.