“Telemedicine has been brought to the forefront of everyone’s practice during the COVID-19 pandemic,” says Evan Silverstein, MD. “Some specialties are well-suited for telemedicine, while others, such as ophthalmology, face more challenges, since the majority of our encounters require in-person examination.” With ophthalmologists facing the need to accurately measure patients’ vision while patients aren’t in the office, Dr. Silverstein and colleagues conducted a study—published in The American Journal of Ophthalmology—to assess the accuracy of at-home measuring protocols for visual acuity in pediatric patients.

Analyzing At-Home Options

To understand the efficacy of parents checking their children’s vision at home, the study team compared visual acuity measured by 3 methods:

  1. The GoCheck Kids app, which provides a visual acuity screener, on an iPhone 7+ used by the patient’s family member. The app displays a test letter in crowding bars (HOTV for children ≤6, ETDRS for children ≥7) below four randomized letters in crowding bars. Children indicate which direction the tester should tilt the device until the test letter matches the letter in the randomized row. The child then notifies the tester of a correct placement of the letter, and the tester tilts the phone downward to lock in the answer.
  2. Study personnel using the HOTV-Amblyopia Treatment Study protocol (HOTV-ATS) used for Pediatric Eye Disease Investigation Group studies on amblyopia.
  3. An ophthalmic technician using the standard protocol (age-appropriate eye chart) in clinic.

Parents or siblings of patients received a short tutorial on how to use the GoCheck app. Patients and testers held a premeasured 5’ rope for GoCheck Kids and sat in the exam chair that was 16’ from the acuity screen for HOTV-ATS and chart acuity to ensure the correct distance was kept throughout the exam.

Promising Results

Dr. Silverstein and colleagues found the at-home systems to be user-friendly and accurate. Testability was 96%, with minimal complications observed with testing. Mean logarithm of the minimum angle of resolution (logMAR; imperial acuity) assessed by the GoCheck Kids app was 0.106 (20/25.5), by HOTV-ATS was 0.012 (20/20.5), and by eye chart was 0.096 (20/22). The mean difference and confidence intervals between GoCheck Kids and chart acuities (0.010, -0.010-0.030) were not significantly different (p=0.319), whereas the mean difference and confidence intervals between HOTV-ATS and chart acuities (0.084, 0.014-0.063) were significantly different (p<0.001). The GoCheck Kids app tested within two lines of the HOTV-ATS and chart acuity in 96.9% of the tests. “It’s encouraging that the data indicate that telemedicine for ophthalmology is possible, for the right patient,” says Dr. Silverstein. “Visual acuity can be measured at home.”

Teleophthalmology Considerations

To help physicians choose the best option(s) for their patients, the researchers compiled a list of options for testing visual acuity remotely, using either a phone or computer (Table). “There are many options to check visual acuity; some are vetted through publications, many are not,” notes Dr. Silverstein. “Clinicians should make sure to pick a method that can be trusted and that is reliable.”

Several patients in the study had a history of monocular amblyopia. Testing revealed minimally varied results in differences of acuity between the amblyopic eye and the non-amblyopic eye, measured by each method. Three patients had a visual acuity that was too low to be tested by the GoCheck Kids app.  “It is known that checking visual acuity in children can show variability,” notes Dr. Silverstein. “As radiologists say, ‘clinical correlation advised.’ Physicians should ensure the vision that is measured makes sense for their patient—if it doesn’t, they should ask for a repeat measurement.”

Dr. Silverstein believes ophthalmologists need to continue to evaluate and validate options for patients to measure visual acuity from home. “Additionally, options for image capture at home should be explored—whether that is mailing equipment to patients or having drive-up clinics for obtaining images that can be later assimilated into a complete virtual visit,” he adds.

Of note; GoCheck has released an updated version of the acuity app—GoCheck Acuity—that is available outside of their screening platform.

References

Teleophthalmology: Evaluation of Phone-based Visual Acuity in a Pediatric Population
https://www.ajo.com/article/S0002-9394(20)30426-8/fulltext