Optometrist-guided versus self-driven subjective refraction using tunable optics: quantifying the professional’s impact

To evaluate the influence of professional guidance on a novel subjective refraction method combining a tunable liquid lens (TLL) and a Stokes lens, and to determine whether clinician involvement affects refractive accuracy, visual outcomes, or testing time compared with a participant-driven approach. Sixty-six participants (18–44 years old) underwent monocular subjective refraction in one randomly selected eye under two conditions: a professional-guided refraction (ORx) performed by an experienced optometrist, and a do-it-yourself (DIY) condition where participants completed the procedure independently. Both methods used the same optical system for continuous spherical and astigmatic adjustment. Three consecutive measurements were taken under repeatability conditions. Refractive components (M, J 0 , J 45 ), visual acuity, and measurement time were compared using Passing–Bablok regression and non-parametric tests. A strong agreement was found between both methods, with slopes including the value 1 within the 95% confidence intervals. Intercepts for the spherical equivalent (M) and time did not include zero, indicating a small systematic bias: M values were slightly more positive and measurement time longer in the ORx condition. This effect was more evident in hyperopic and near-emmetropic eyes. No statistically significant differences were observed between methods (p > 0.05). Both techniques showed a learning effect with reduced time across repetitions. DIY subjective refraction achieved comparable accuracy and visual outcomes to professional-guided procedures. While clinician supervision improved consistency and accommodative control, the DIY approach demonstrated feasibility as a complementary and accessible option for hybrid or remote refraction applications.