The Effect of Low Power Glasses at Close Distances on Visual Performance

Abstract

The purpose of this study was to reveal if the use of low power ophthalmic glasses (diopter values within the ± 1.00D range) in ophthalmic care may be beneficial for the treatment of low refractive vision disorders. 40 university students (10 men, 30 women), who used low power glasses at close distances (for reading on paper or on a computer screen: 40–60 centimeters approximately), voluntarily took part in this study. Ages of the participants ranged from 20 to 43 years ( M = 24.9, SD = 4.4). Mean spherical refractive error was −0.38 diopters ( SD = 0.49; range = −1.00-0.88). A yes/no Signal Detection procedure was used to assess whether the participants' visual sensitivity ( d') or criterion of response ( c) changed when they used the optical correction. There were no changes in visual sensitivity index, but significant changes in criterion of response were observed when the students used their optical correction. Changes in the criterion of response suggested the presence of a placebo effect.