A novel smartphone App to support the clinical practice of pediatric ophthalmology and strabismus: the validation of visual acuity tests

This study is aimed at describing the TreC Oculistica novel smartphone App that facilitated the clinical practice of pediatric ophthalmology and strabismus during the COVID-19 pandemic and at reporting on the validation of visual acuity tests in a home setting. The Trec Oculistica smartphone App was prescribed to eligible patients at the Pediatric Ophthalmology and Strabismus Clinic, Ophthalmology Unit of Rovereto Hospital, between September 2020 and March 2022. Four key indicators were identified for monitoring visual and visuo-motor functions remotely: visual acuity, ocular motility, head posture, and color vision. Clinicians selected few mobile applications (iOS, Android) and printable materials within the Trec Oculistica App: the Snellen Chart Visual Acuity App, the 9Gaze App, the eyeTilt App, the Color Blind test App, the LEA Symbols pdf, and the Snellen Chart pdf. All patients, aged 4 and older, were screened at home for visual acuity at 3 m and later in the clinic (LEA Symbols cabinet or Snellen computerized optotype). The 9Gaze, the eyeTilt, and the Color Blind test Apps were only recommended to a subset of patients based on clinical suspicion or diagnosis. The Wilcoxon signed rank sum test and weighted Cohen's kappa coefficient were applied to compare pairs of scores from different settings. The Trec Oculistica App was downloaded and activated by 97 patients or their caregiver. 40 patients were tested at home using the 9Gaze App, 7 used the eyeTilt App, and 11 used the Color-Blind test App. Families reported that all the Apps were easy and intuitive to use; clinicians reported that measurements were reliable. 82 eyes of 41 patients (mean age 5.2 years, SD ± 0.4, range 4.4-6.1) were tested for visual acuity using the self-administered LEA Symbols pdf. 92 eyes of 46 patients (mean age 11.6 years, SD ± 5.2, range 6-35) were evaluated using the self-administered Snellen Chart Visual Acuity App or the Snellen Chart pdf. Home median visual acuity score was statistically different from that registered in clinical setting for both the LEA Symbols pdf (P-value = 0.0074) and the Snellen Chart App and pdf (P-value = 0.0001). The strength of agreement was 0.12 (slight) for the LEA Symbols pdf, 0.50 (moderate) for the Snellen Chart Visual Acuity App, and 0.69 (substantial) for the Snellen Chart pdf. Conclusion: The novel TreC Oculistica smartphone App was a useful tool for facilitating the clinical practice of pediatric ophthalmology and strabismus during the COVID-19 pandemic. In the follow-up of strabismus patients and patients with suspected inherited retinal diseases, the 9Gaze, eyeTilt, and Color Blind test applications were deemed to be intuitive and easy to use by families and were considered reliable by clinicians. In a home setting, visual acuity tested by means of Snellen Charts was moderately congruent with the in-office examination. On the contrary, agreement was poor in younger children tested with the LEA Symbols pdf. What is known: • Teleophthalmology enables clinicians to evaluate patients' ocular diseases remotely and various tools are helpful for screening, follow-ups and treatment. • Smartphones can currently be used to obtain ocular images and vision measurements of patients' eyes and this information can be shared with the ophthalmologist for further evaluations and medical management (mhealth). What is new: • Smartphone Apps can be successfully used in a hybrid teleophthalmology service concerning first visits and follow-ups. • Apps and printable materials are easy, intuitive to use for patients and  also reliable for  clinicians.