Comparing the Netra smartphone refractor to subjective refraction

• Published in: Clinical and experimental optometry 2020-07, Vol.103 (4), p.501-506
• Main Authors: Tousignant, Benoit, Garceau, Marie-christine, Bouffard-saint-pierre, Nikola, Bellemare, Marie-maxime, Hanssens, Jean-marie
• Format: Article
• Language: English
• Subjects: Acuity; diagnostic techniques; Eye; instrumentation; Medical diagnosis; ocular; ophthalmological instrumentation; Refraction; refractive errors; Smartphones; Telemedicine; vision tests
• ISSN: 0816-4622; 1444-0938
• DOI: 10.1111/cxo.13003

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. 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. 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