Validation of Digital Applications for Evaluation of Visual Parameters: A Narrative Review

Abstract

The current review aimed to collect and critically analyze the scientific peer-reviewed literature that is available about the use of digital applications for evaluation of visual parameters in electronic devices (tablets and smartphones), confirming if there are studies calibrating and validating each of these applications. Three bibliographic search engines (using the search equation described in the paper) and the Mendeley reference manager search engine were used to complete the analysis. Only articles written in English and that are evaluating the use of tests in healthy patients to measure or characterize any visual function aspects using tablets or smartphones were included. Articles using electronic visual tests to assess the results of surgical procedures or are conducted in pathological conditions were excluded. A total of 19 articles meeting these inclusion and exclusion criteria were finally analyzed. One critical point of all these studies is that there was no mention of the characterization (spatial and/or colorimetrical) of screens and the stimuli used in most of them. Only two studies described some level of calibration of the digital device before the beginning of the study. Most revised articles described non-controlled comparatives studies (73.7%), reporting some level of scientific evidence on the validation of tools, although more consistent studies are needed.

Validity and Reliability of Vis-Screen Application: A Smartphone-Based Distance Vision Testing for Visual Impairment and Blindness Vision Screening

“…The main priority for any new screening tool is accuracy and validity. Despite the abundance of eye testing apps available in the virtual market, the scarcity of validated apps, mainly for visual acuity screening, added another challenge [ 6 ]. For this study, the Vis-Screen app had the highest sensitivity of 88% for PVR at the 6/12 cut-off point.…”

“…These include the most popular Tumbling E, followed by Early Treatment Diabetic Retinopathy Study (ETDRS), and Snellen charts [ 5 ]. Even though these existing apps could provide another option for vision screening, most of them need to be appropriately validated, thus raising the biggest concern toward their safety and accuracy [ 3 , 6 ]. Regardless of the platform, a validated app is essential to ensure that the number of false positives and negatives are minimal so that both misleading results and the burden of unnecessary referrals to health providers can be reduced [ 7 , 8 ].…”

Ease and willingness to use Smartphone applications for visual acuity assessment among patients in Ahmadu Bello University Teaching Hospital, Zaria

“…Various factors such as the variability of the smartphone screen sizes, screen resolution, optotype background luminance, and glares may affect the accurate generation of the necessary visual stimuli (optotype) and hence the accuracy of the measurements made across different devices. [ 13 ] To avoid this, app developers may use autocalibration by the software itself or manual calibration using a set of given instructions. This process of calibration may however make the user interface of the application to appear complex and unfriendly.…”