In-home Accustat vision test: Equivalent results to in-office Snellen measurements

The investigators compared the measurements of the best-corrected VA obtained using a Snellen chart with the remote VA assessment using the at-home Accustat test. Image credit: ©Halfpoint – stock.adobe.com

The COVID-19 pandemic brought a number of different factors into sharp focus for clinicians, an important one being the need to be able to follow patients with retinal diseases remotely and accurately. A recent study¹ evaluated how well the Accustat test (KeepYourSight), a virtual application for measuring near visual acuity (VA), performed during the constrained conditions of the pandemic.

Earnest P. Chen, MD, and senior author Sean Ianchulev, MD, reported that the test proved to be efficient for measuring the near VA, an important component of the retinal function, and the results were well correlated with the Snellen acuity measured during in-office examinations. Dr Chen is from the Department of Ophthalmology of the Icahn School of Medicine at Mount Sinai, and New York Eye and Ear Infirmary of Mount Sinai, both in New York; Dr Ianchulev is from the Department of Ophthalmology of the Icahn School of Medicine at Mount Sinai.

The investigators emphasised the “significant unmet need for remote monitoring of visual function with home-based, patient-centric technologies. This became increasingly palpable during the COVID-19 pandemic in 2020 when many patients with chronic eye conditions such as age-related macular degeneration, glaucoma and diabetic retinopathy did not have access to office-based examinations.”

Many vision applications are in the pipeline, but clinical validation of the efficacy of the remote applications is lacking, which prompted the investigators to evaluate the Accustat test.

Drs Chen and Ianchulev noted that recent studies of the home use of
monitoring devices in patients with retinal disease reported the high sensitivity and specificity values for the early detection of recent-onset choroidal neovascularisation and disease progression using the Foresee preferential hyperacuity perimetry device^2,3 (Notal Vision) and the promisingsmartphone test.⁴

In the study under discussion, the at-home efficacy of the remote Accustat test was evaluated in 33 adult subjects from the remote monitoring service of a retina practice. All study participants underwent a general eye examination in the office, a funduscopic examination and optical coherence tomography imaging. The Accustat test is a virtual application that can be used to measure near VA on portable devices via telehealth.

The investigators also wanted to determine if there was a correlation between distance and near-best-corrected VAs as 2 related surrogates of the central retinal function, they explained. “The near VA is a critical visual function that, when compromised, has been shown to have as great an adverse impact on quality of life and functioning in older adults as a decline in distance VA.5-7 More importantly, assessment of the near VA can be more impactful from a screening and monitoring perspective as it is easier to measure remotely and is better able to leverage existing digital technology,” they said.

Evaluation of the Accustat test

The investigators compared the measurements of the best-corrected VA obtained using a Snellen chart with the remote VA assessment using the Accustat test.

The investigators reported similar findings for the 2 VA measurements that they compared, which suggested the usefulness of the virtual test for close follow-up of patients with retinal disorders.

“The mean logarithm of the minimum angle of resolution [logMAR] VAs of all eyes tested using the Accustat test was 0.19 ± 024 and for the in-office Snellen test 0.21 ± 0.21. A linear regression model with 95% confidence intervals showed a strong linear relationship between the Accustat logMAR vision and the in-office Snellen logMAR vision. Bland-Altman analysis demonstrated 95.2% significant agreement between the Accustat and office Snellen’s best-corrected VAs. The intraclass correlation coefficient (ICC = 0.94) demonstrated a strong positive correlation between at home versus office VA,” they reported.

The investigators commented that patients’ ability to monitor their retinal function using the Accustat test, “offers significant advantages to extend the clinical practice outreach beyond the medical office into the patients’ homes. The high correlation between the near best-corrected digital VA and office distance best-corrected Snellen VA opens up new avenues to leverage consumer electronic devices in the assessment of visual function for a range of clinical and public health applications."

References

1. Chen EP, Mills M, Gallagher T, et al. and the Accustat Study Group. Remote vision testing of central retinal acuity and comparison with clinic-based Snellen acuity testing in patients followed for retinal conditions. Digit Health. 2023;9:20552076231180727. Published online 4 June 2023. doi: 10.1177/20552076231180727

2. Alster Y, Bressler NM, Bressler SB, et al.Preferential hyperacuity perimeter (PreView PHP) for detecting choroidal neovascularization study. Ophthalmology. 2005;112:1758–1765.

3. Busquets MA, Sabbagh O. Current status of home monitoring technology for age-related macular degeneration.Curr Opin Ophthalmol. 2021;32:246.

4. Bastawrous A, Rono HK, Livingstone IA, et al. Development and validation of a smartphone-based visual acuity test (peek acuity) for clinical practice and community-based fieldwork. JAMA Ophthalmol. 2015;133:937.

5. Reyes-Ortiz CA, Kuo YF, DiNuzzo AR, et al. Near vision impairment predicts cognitive decline: data from the Hispanic established populations for epidemiologic studies of the elderly. J Am Geriatr Soc. 2005;53:686.

6. Keller BK, Morton JL, Thomas VS, Potter JF. The effect of visual and hearing impairments on functional status. J Am Geriatr Soc. 1999;47:13191325.

7. Klein BE, Moss SE, Klein R, et al. Associations of visual function with physical outcomes and limitations 5 years later in an older population: the Beaver Dam eye study. Ophthalmology. 2003;110:644650.

Sean Ianchulev, MD

Dr Ianchulev is a professor of Ophthalmology at New York Eye and Ear of Mount Sinai, as well as the director of the programme for technology and innovation. He is an inventor and patent application holder, and the founder and Chairman of the Board of Eyenovia.

Earnest P. Chen, MD

Dr Chen is from the Department of Ophthalmology of the Icahn School of Medicine at Mount Sinai, and New York Eye and Ear Infirmary of Mount Sinai, both in New York. He has no financial interest in this subject matter.