Assessment of an algorithm-based combination device for objective and subjective refraction: accuracy and efficiency...

A novel combination device for objective and subjective refraction was assessed regarding repeatability, reproducibility, validity, vision quality, and timing for experienced and untrained examiners.

Six examiners (each three trained optometrists and untrained examiners) examined 33 healthy participants for objective and subjective refraction. The ZEISS VISUCORE 500 (VC) objective and subjective refraction combination device with an algorithm-based guided and regular custom mode was compared to a conventional control procedure (wavefront aberrometer and phoropter).

For the objective measurement of spherical equivalent refractive error (SE), VC shows good repeatability (≤ ±0.29 D) and reproducibility (≤ ±0.28 D) across all examiners versus control (±0.34 D and ≤ ±0.30 D, respectively), measured only by trained examiners. VC measures slightly negative objective refractions for SE with a mean difference (MD) and 95% limits of agreement (LoA) of -0.07 ± 1.24 D analyzed for a trained examiner. Subjective refraction for VC guided and custom mode showed good repeatability (≤ ±0.64 D) and reproducibility (≤ ±0.59 D) regarding SE for the examiner level. The results were similar to control (±0.54 D and ±0.51 D, respectively) with MD and LoA of +0.12 ± 0.67 D and +0.14 ± 0.66 D for VC guided and custom for trained examiner level. No significant differences were observed in best-corrected visual acuity across the three refraction workflows (all p > 0.05). The VC guided procedure was the most time-efficient, requiring less than 5 min of chair time.

The tested combination refraction device provides reliable and efficient objective and subjective refraction measurements across trained and untrained examiners.