Evaluation of objective and subjective binocular ocular refraction with looking in type

Background: This study aimed to compare the consistency of objective and subjective ocular refraction using automated binocular refraction system that performs binocular objective ocular refraction and subjective ocular refraction in a single unit with objective ocular refraction using a conventional autorefractometer and conventional subjective ocular refraction in real space. Methods Twenty-eight healthy volunteers (21.2 ± 1.5 years old) participated in this study. The objective ocular refractions in the right eye were measured using an automated binocular refraction system and a conventional autorefractometer. The subjective ocular refractions were measured binocular and monocular conditions using the automated binocular refraction system and monocular condition in real space at 5.0 m. The objective and subjective ocular refractions were converted to spherical equivalents (SEs). Results The objective SE was significantly and negatively greater with the automated binocular refraction system (objective − 4.08 ± 2.76 D) than with the conventional autorefractometer (objective − 3.85 ± 2.66 D) ( P  = 0.002). The subjective SE was significantly and negatively greater with the automated binocular refraction system (− 3.55 ± 2.67 D) than with the real space (− 3.33 ± 2.75 D) ( P  = 0.002). The subjective SE measured under monocular condition with the automated binocular refraction system (− 3.17 ± 2.57 D) was not significantly different from those in the real space ( P  = 0.33). Conclusion The objective and subjective SEs were significantly and negatively greater using the binocular refraction system than in real space. However, the differences were < 0.25 D. These findings suggest that automated binocular refraction system has sufficient performance for clinical use. Trial registration number: UMIN000039665