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Randomized Controlled Trial
. 2020 Jul;103(4):501-506.
doi: 10.1111/cxo.13003. Epub 2019 Nov 26.

Comparing the Netra smartphone refractor to subjective refraction

Benoit Tousignant  1 , Marie-Christine Garceau  1 , Nikola Bouffard-Saint-Pierre  1 , Marie-Maxime Bellemare  1 , Jean-Marie Hanssens  1
Affiliations
Free article
Randomized Controlled Trial

Comparing the Netra smartphone refractor to subjective refraction

Benoit Tousignant et al. Clin Exp Optom. 2020 Jul.
Free article

Abstract

Background: Among technologies targeting mobile eye care, EyeNetra is a smartphone-based subjective refraction system. This study compared the results from this system with those of professional subjective refraction. Participant visual comfort and preference of results were also measured.

Methods: Thirty-six optometry-naïve participants (n = 36 eyes, aged 18-35 years), were randomly subjected to three refraction methods: professional subjective refraction, unassisted Netra (participants alone) and refined Netra (sphere results refined by a practitioner). Using a randomised, double-blind design, refraction results were mounted in a trial frame and distance logMAR visual acuities were measured. Subjective appreciation and visual comfort were assessed by questionnaire. Overall preference was ranked.

Results: Unassisted Netra yielded a median myopic overcorrection of 0.60 D (interquartile range [IQR] 0.25 to 0.94) compared to professional subjective refraction. Median equivalent sphere with unassisted Netra (-1.40 D, IQR -3.10 to -0.90) was significantly more myopic than refined Netra (-0.70 D, IQR -1.60 to -0.30) and then subjective refraction (-0.80 D, IQR -1.60 to -0.30) (all p-values < 0.01). Median visual acuity with professional subjective refraction (-0.16, IQR -0.22 to -0.09) was superior than unassisted Netra (-0.08, IQR -0.20 to 0.03) (p < 0.01). Subjective refraction was ranked first in preference of trial framed results by 72 per cent of participants; median preference rank favoured professional subjective refraction to both Netra results (all p < 0.01). For all questionnaire items, visual comfort was higher with subjective refraction than with unassisted Netra (all p < 0.04).

Conclusion: The Netra device - especially when used without professional assistance and compared to subjective refraction - induces significant myopic overcorrection and lower levels of visual acuity, subjective preference and visual comfort.

Keywords: diagnostic techniques; instrumentation; ocular; ophthalmological instrumentation; refractive errors; telemedicine; vision tests.

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References

REFERENCES

    1. Bourne RRA, Flaxman SR, Braithwaite T et al. Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis. Lancet Glob Health 2017; 5: e888-e897.
    1. Resnikoff S, Pascolini D, Mariotti SP et al. Global magnitude of visual impairment caused by uncorrected refractive errors in 2004. Bull World Health Organ 2008; 86: 63-70.
    1. Rathi S, Tsui E, Mehta N et al. The current state of teleophthalmology in the United States. Ophthalmology 2017; 124: 1729-1734.
    1. Mohammadpour M, Heidari Z, Mirghorbani M et al. Smartphones, tele-ophthalmology, and VISION 2020. Int J Ophthalmol 2017; 10: 1909-1918.
    1. Pamplona V, Raskar R. Methods and Apparatus for Eye Relaxation. United States Patent and Trademark Office. Patent number PCT/US2013/051412. [Cited 2019 Mar 22]. Available at: https://www.uspto.gov/.

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