Myopic eyes have reduced accommodative facility at distance, and accommodative responsiveness to both positive and negative defocus is slow. However, accommodative facility as a test does not have sufficient power to discriminate eyes with myopia from other refractive errors.

The COAS G200 aberrometer was an easy-to-use instrument for the measurement of refractive error in children. In addition to being able to measure higher and lower order aberrations, the COAS G200 provides refractive error measurements comparable to those of an autorefractor.