As noted above, in general, with reflexes are brighter, sharper, and easier to perceive and interpret than against reflexes. In particular, the reflex in severely myopic eyes is seldom recognizable as an against reflex—rather, one sees only a dull, motionless illumination of the entire pupil. This is referred to as pseudoneutralization. This is best handled by reversing the sleeve of the retinoscope (to the maximal sleeve-up position for Welch-Allyn type retinoscopes; maximal sleeve-down position for Copeland retinoscopes). This will convert the dull pseudoneutral reflex to a readily recognizable with reflex, but in this case, the with reflex must be neutralized by adding minus sphere power. As true neutrality is approached, return the retinoscope sleeve to the usual position. The reflex will revert to an against reflex as in typical myopic eyes. Continue to add minus sphere power until a with reflex is obtained, and then reduce the minus sphere so as to reach true neutrality from the with direction. Video 4-4 demonstrates pseudoneutralization.
Table 4-1 Retinoscopy Summary (Using a Plus Cylinder Phoropter)
Animation developed by Thomas F. Mauger, MD.
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.