title: Steps towards Smarter Solutions in Optometry and Ophthalmology-Inter-Device Agreement of Subjective Methods to Assess the Refractive Errors of the Eye.
abstract: OBJECTIVE
  To investigate the inter-device agreement and mean differences between a newly developed digital phoropter and the two standard methods (trial frame and manual phoropter).
  
  
  METHODS
  Refractive errors of two groups of participants were measured by two examiners (examiner 1 (E1): 36 subjects; examiner 2 (E2): 38 subjects). Refractive errors were assessed using a trial frame, a manual phoropter and a digital phoropter. Inter-device agreement regarding the measurement of refractive errors was analyzed for differences in terms of the power vector components (spherical equivalent (SE) and the cylindrical power vector components J0 and J45) between the used methods. Intraclass correlation coefficients (ICC's) were calculated to evaluate correlations between the used methods.
  
  
  RESULTS
  Analyzing the variances between the three methods for SE, J0 and J45 using a two-way ANOVA showed no significant differences between the methods (SE: p = 0.13, J0: p = 0.58 and J45: p = 0.96) for examiner 1 and for examiner 2 (SE: p = 0.88, J0: p = 0.95 and J45: p = 1). Mean differences and ±95% Limits of Agreement for each pair of inter-device agreement regarding the SE for both examiners were as follows: Trial frame vs. digital phoropter: +0.10 D ± 0.56 D (E1) and +0.19 D ± 0.60 D (E2), manual phoropter vs. trial frame: -0.04 D ± 0.59 D (E1) and -0.12 D ± 0.49 D (E2) and for manual vs. digital phoropter: +0.06 D ± 0.65 D (E1) and +0.08 D ± 0.45 D (E2). ICCs revealed high correlations between all methods for both examiner (p < 0.001). The time to assess the subjective refraction was significantly smaller with the digital phoropter (examiner 1: p < 0.001; examiner 2: p < 0.001).
  
  
  CONCLUSIONS
  "All used subjective methods show a good agreement between each other terms of ICC (>0.9). Assessing refractive errors using different subjective methods, results in similar mean differences and 95% limits of agreement, when compared to those reported in studies comparing subjective refraction non-cylcoplegic retinoscopy or autorefraction".
authors.affiliation: Institute for Ophthalmic Research, University of Tuebingen, Geschwister-Scholl-Platz, 72074 T&#252;bingen, Germany. arne.ohlendorf@zeiss.com.|Carl Zeiss Vision International GmbH, 73430 Aalen, Germany. arne.ohlendorf@zeiss.com.
authors.forename: Arne
authors.initials: A
authors.lastname: Ohlendorf
authors.affiliation: Institute for Ophthalmic Research, University of Tuebingen, Geschwister-Scholl-Platz, 72074 T&#252;bingen, Germany. alexander.leube@uni-tuebingen.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Leube
authors.affiliation: Institute for Ophthalmic Research, University of Tuebingen, Geschwister-Scholl-Platz, 72074 T&#252;bingen, Germany. siegfried.wahl@uni.tuebingen.de.|Carl Zeiss Vision International GmbH, 73430 Aalen, Germany. siegfried.wahl@uni.tuebingen.de.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wahl
keywords: agreement; optometry; public health; refractive errors; subjective refraction