Wittenberg S
School of Optometry, InterAmerican University of Puerto Rico, Hato Rey.
Am J Optom Physiol Opt. 1988 Apr;65(4):285-91. doi: 10.1097/00006324-198804000-00008.
Badal's optometer is used to change the vergence of the accommodative stimulus without changing retinal image size. It has been accepted that this can be accomplished by putting the optometer's secondary focal point at either the eye's anterior nodal or anterior focal point. I show that there can be only one solution because the simultaneous truth of both solutions would lead to a paradox. The most precise solution is slightly different for the accommodated and the unaccommodated eye, but the nodal point provides the best general solution. For the accommodating eye there is a residual increase in image size with accommodation due to the anterior displacement of the nodal points. For the unaccommodated eye, the correct reference point is its entrance pupil. Use of the nodal point results in accommodation creating an anomalous, but slight, change in retinal image size.
巴达尔验光仪用于在不改变视网膜图像大小的情况下改变调节刺激的聚散度。人们已经公认，这可以通过将验光仪的次焦点置于眼睛的前节点或前焦点来实现。我证明只能有一个解决方案，因为两个解决方案同时成立会导致悖论。对于调节眼和未调节眼，最精确的解决方案略有不同，但节点提供了最佳的通用解决方案。对于调节眼，由于节点向前移位，调节时图像大小会有残余增加。对于未调节眼，正确的参考点是其入瞳。使用节点会导致调节时视网膜图像大小产生异常但轻微的变化。
