Study Supports Voice-Guided Subjective Refraction Device

Eye Examination For Children. Ophthalmology. Auto refractometer
Researchers say an AI device’s refraction nerely matches an optometrist’s results.

The following article is a part of conference coverage from the American Academy of Ophthalmology 2020, being held virtually from November 13 to 15, 2020. The team at Ophthalmology Advisor will be reporting on the latest news and research conducted by leading experts in ophthalmology. Check back for more from the AAO 2020.

With a telemedicine setting in mind, researchers presenting at the American Academy of Ophthalmology 2020 meeting sought to evaluate the accuracy of the Vmax voice-guided subjective refraction (VASR) machine. This machine is described as patient driven and uses artificial intelligence (AI) to guide the patient through the exam process. 

A study was conducted with 50 participants, evaluating both eyes for each participant (100 eyes total). Everyone included had a visual acuity (VA) correctable to 20/25 or better. 

All participants received a refraction by both VASR operated by a technician with no prior refracting experience and an optometrist using a phoropter. To compare statistics, the researchers used the Wilcoxon signed rank test. 

They were able to show that the  VASR machine was as accurate as an optometrist in performing a manifest refraction. There were no significant differences in manifest refraction between the 2 methods in terms of sphere (OD: P =.27; OS: P =.24), cylinder (OD: P =.34; OS: P =.23), axis (OD: P =.60; OS: P =.33) or spherical equivalent (OD: P =.34; OS: P =.23). The median VA for the VASR (-0.1OD, 0.0 OS logMAR) was essentially equivalent to that of the optometrist (0.0 OD, 0.0 OS logMAR) (P < .01).

As telemedicine expands, practitioners’ access to accurate technology can increase individuals’ access to quality care remotely. These findings support the potential for the VASR machine to be a valuable tool, especially in telemedicine. 


Binder N. Validation of a novel ai-guided manifest refraction tool for use in telemedicine. Presented at: American Academy of Ophthalmology 2020 Annual Meeting; November 13-15, 2020. Abstract PO318.

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