Clinical evaluation of Nidek autorefractometer AR‐360A

Abstract

PurposeA clinical evaluation of the Nidek AR‐360A autorefractometer was performed to examine its accuracy in measuring refraction and visual acuity, in a pilot study for a clinical screening trial (the Northern Finland Birth Cohort Eye Study).MethodsMeasurements of the refractive error were obtained from 160 eyes of 80 subjects (mean age 48.9), first objectively with the AR‐360A and then subjectively by an optometrist. Agreement with the subjective refraction was calculated for sphere, cylinder, mean spherical equivalent (MSE), cylindrical vectors J45 and J0, and presbyopic correction (add). Visual acuity was measured using an ETDRS chart and the autorefractometer. The central corneal thickness (CCT) was measured with pachymetry.ResultsThe refractive error measured with the AR‐360A was lower than the subjective refraction performed by the optometrist for sphere (−0.13D ± 0.31D p < 0.0005), and higher for cylinder (0.11D ± 0.18D p < 0.0005). The bias between the measurements of MSE, J45 and J0 was very low; −0.08D ± 0.31D p = 0.002, 0.00D ± 0.43D p = 0.89, and 0.19D ± 0.36D p = 0.51, respectively. The amount of add measured by the autorefractometer was slightly higher at 0.16D ± 0.23D p < 0.0005. There was no statistically significant correlation with either visual acuity (p = 0.650) or CCT (p = 0.054) and the difference between the subjective and objective refraction. In 99.4% of the measurements of visual acuity using the ETDRS chart and the autorefractometer, values were within one Snellen line of each other.ConclusionsThe Nidek AR‐360A autorefractometer is a reliable tool for determining the refraction and visual acuity in a clinical screening trial.