Comparison of Two Wavefront Autorefractors: Binocular Open-Field versus Monocular Closed-Field

Abstract

Purpose. To evaluate the agreement and repeatability between a new commercially available binocular open-field wavefront autorefractor, as part of the Eye Refract system, and a monocular closed-field wavefront autorefractor (VX110). Methods. A cross-sectional, randomized, and single-masked study was performed. Ninety-nine eyes of 99 healthy participants (37.22 ± 18.04 years, range 8 to 69 years) were randomly analyzed. Three measurements with the Eye Refract and the VX110 were taken on three different days, under noncycloplegic conditions. Mean spherical equivalent (MSE), cylindrical vectors (J0 and J45), and binocular corrected distance visual acuity (BCDVA) were compared between both autorefractors. An intersession repeatability analysis was done considering the values of repeatability (Sr) and its 95% limit (r). Results. The VX110 showed more negative values (P<0.001) in terms of MSE in comparison with the Eye Refract (0.20 D). Regarding cylindrical vectors, J45 showed statistically significant differences (P=0.001) between both wavefront autorefractors, but they were not clinically relevant (<0.05 D). In BCDVA, there were no statistically significant differences (P=0.667) between both wavefront autorefractors. Additionally, the Eye Refract was more repeatable than the VX110 in terms of both MSE (SrEYE REFRACT = 0.21 D, SrVX110 = 0.53 D) and J0 (SrEYE REFRACT = 0.12 D, SrVX110 = 0.35 D). Conclusions. The Eye Refract provided enough accuracy and reliability to estimate refractive errors in different age groups, achieving better results than the VX110. Therefore, the Eye Refract proved to be a useful autorefractor to be incorporated into clinical practice.

Effect of Instrument Design and Technique on the Precision and Accuracy of Objective Refraction Measurement

“…This interval is considerably large clinically and thus these instruments cannot be used interchangeably. Many of the previous studies have also shown similar large limits of agreement intervals [ 7 , 10 , 23 , 24 ]. The difference in the objective refraction values obtained with different autorefractometers are suggested to be caused by the fixation target, viewing conditions, fogging system, and wavefront sensors for measurements [ 23 , 24 ].…”

“…Our precision results showed good repeatability and reproducibility outcomes, and the limits never exceeded 0.70D for M and 0.40D for the cylindrical components. The autorefractometers available for clinical use have been shown to have good repeatability and reproducibility for measuring the objective refraction [ 7 , 14 , 18 , 19 , 20 ]. With the introduction of new instruments, the intra- and inter-session precision needs to be evaluated, although the objective refraction measurements are automated and are seldom influenced by the examiner.…”

“…Depending on the autorefractometer used, the objective refraction measurements can be performed either with or without fogging, monocular or binocular, through the central or the whole pupil, and with or without open-field viewing. The results of objective refraction measurements vary among autorefractors, and those differences are in most cases clinically significant [ 6 , 7 , 8 ]. This could be explained due to the measurement principle and design of each.…”

Repeatability of Aberrometry-Based Automated Subjective Refraction in Healthy and Keratoconus Subjects

“…They found similar values of repeatability for the sphere ( r = 1.96 D ; ICC = 0.983) compared to the Eye Refract in the keratoconus group (see Table 3 ). In healthy subjects, several studies measured objective refraction with different aberrometers, obtaining r values between 0.28 D and 0.59 D for the spherical equivalent [ 16 , 26 – 30 ]. These values were slightly better than the ones obtained with the Eye Refract in the healthy group (see Table 3 ).…”

“…The accuracy and precision of the Eye Refract to estimate refractive errors has been confirmed in healthy subjects [ 14 , 16 ]. However, its repeatability to perform automated subjective refraction is still unknown in healthy subjects and other ocular conditions.…”