Evaluation of an open-field autorefractor's ability to measure refraction and hence potential to assess objective accommodation in pseudophakes.

BACKGROUND

To evaluate the accuracy of an open-field autorefractor compared with subjective refraction in pseudophakes and hence its ability to assess objective eye focus with intraocular lenses (IOLs).

METHODS

Objective refraction was measured at 6 m using the Shin-Nippon NVision-K 5001/Grand Seiko WR-5100K open-field autorefractor (five repeats) and by subjective refraction on 141 eyes implanted with a spherical (Softec1 n=53), aspherical (SoftecHD n=37) or accommodating (1CU n=22; Tetraflex n=29) IOL. Autorefraction was repeated 2 months later.

RESULTS

The autorefractor prescription was similar (average difference: 0.09 ± 0.53 D; p=0.19) to that found by subjective refraction, with ∼71% within ± 0.50 D. The horizontal cylindrical components were similar (difference: 0.00 ± 0.39 D; p=0.96), although the oblique (J(45)) autorefractor cylindrical vector was slightly more negative (by -0.06 ± 0.25 D; p=0.06) than the subjective refraction. The results were similar for each of the IOL designs except for the spherical IOL, where the mean spherical equivalent difference between autorefraction and subjective was more hypermetropic than the Tetraflex accommodating IOL (F=2.77, p=0.04). The intrasession repeatability was <0.55 D (95% CI) and intersession repeatability <0.50 D in ≥ 85%.

CONCLUSIONS

The autorefractor gives valid and repeatable measures of pseudophakic eye refraction and hence objective accommodation.