屈光不正评价指标及其参数关系的定性分析

Qualitative analysis of the evaluation indicators and their related parameters of ametropic state

目的探讨屈光不正评价中现有计算公式的理论依据和实用局限。方法采用简约模型眼、旁轴成像物距像距关系和量纲法则分析现有公式的评价指标及其计算参数。结果（1）现有公式来自物距像距关系式中物折合聚散力（reducedobjectvergence），聚散力即屈光力（refractivepower）；（2）现有公式评价屈光不正的两个计量指标中屈光度为屈光力的误用，屈光不正度为不规范用语，二者均不适于作为屈光不正的评价指标；（3）现有公式的计算结果及其符号规则表示的是屈光矫正而不是屈光不正，屈光不正自身目前尚无合适的计量评价指标。结论屈光不正评价中，现有公式来自物折合聚散力，其基本问题是计量指标和单位存在混淆和混用，其计算结果按照现行符号规则表示的仅是屈光矫正。屈光不正自身的评价指标有待另行探讨。

Objective To investigate the theoretical basis and practical limitations of the existing calculation formulas in the evaluation of ametropic state. Methods The evaluation indicators and their calculation parameters of ametropia were analyzed by using the reduced schematic model eye, the paraxial imaging principle, and the dimension laws. Results The existing formulas resulted from the reduced object vergence of object distance and image distance relation. Regarding the two measurement indicators of the existing formulas, diopter was misused for refractive power. ＂Ametropia degree＂ was a non-standard diction. Both of them were not suitable as the evaluation indicators. The outcomes of the existing formulas and their related plus or minus sign rules showed refractive corrections instead of refractive errors proper. For refractive errors, there was no suitable evaluation indicator. Conclusions In the evaluation of ametropic state, there are fundamental problems in the existing formulas resulting from the reduced object vergence. The measurement indicators and their dimensional units are confused and misused. The calculation results refer to the refractive corrections only. The evaluation indicators for ametropia need to be further discussed.