Comparison of Ocular Wavefront in Seated and Supine Positions Using a Hand-Held Hartmann-Shack Aberrometer.

Background/Objectives: Intraoperative aberrometry has gained clinical relevance in correcting aberrations during cataract and corneal refractive surgeries. As wavefront aberrations are typically measured with patients seated, while surgeries are performed supine, this study aimed to compare ocular aberrations between seated and supine positions, using a hand-held Hartmann-Shack aberrometer. Methods: Total ocular wavefront aberrations were measured five times consecutively from cyclopledged eyes for a 6 mm pupil, under three conditions: (1) seated with a holder-fixed mode (reference), (2) seated with a hand-held mode, and (3) supine with a hand-held mode. Condition 2 was included to assess potential measurement errors from the hand-held mode. Repeatability was assessed using the standard deviation of repeated measurements (Srm) and the intraclass correlation coefficient (ICC). Differences among the three conditions were analyzed to evaluate the effects of positional change and hand-held stability on ocular wavefront aberration measurements. Results: Eighteen healthy subjects (36 eyes) were enrolled. The Srms for the sphere were 0.37, 0.38, and 0.40 diopters (D); and for the cylinder, 0.10, 0.10, and 0.11 D, with no significant differences across conditions. ICC values exceeded 0.9 for both lower-order aberrations (LOAs) and higher-order aberrations (HOAs), indicating excellent repeatability. The mean root mean square HOAs (HOA_RMS) were 0.48, 0.49, and 0.45 µm, with no statistically significant differences by position (p = 0.913) or measurement mode (p = 0.966). Conclusions: The hand-held Hartmann-Shack aberrometer demonstrated satisfactory repeatability for LOAs and HOAs. Supine measurements did not differ from seated, supporting the feasibility of extending preoperative results to intraoperative aberrometry, regardless of positional differences.