Dark Focus: Intersubject Variation, Intrasubject Stability, and Relationship to Near Retinoscopy

摘要

Previous studies have shown that dark focus varies between individuals while remaining relatively fixed over time. These relationships were quantified in a population of future naval aircrewmen to determine whether or not individual variability exists in a group who have met stringent visual screening requirements. In addition, it has been reported that near retinoscopy, a clinical measure, is a means to determine dark focus that may be used by clinicians. The relationship between near retinoscopic values and dark focus measures needed further study. This study found that dark focus exhibited intersubject variation and intra-subject stability in a population of future naval aircrewmen. Because dark focus is correlated with empty field myopia, it could have potential in screening aviators for susceptibility to empty field myopia and their ability to detect air-to-air targets. Near retinoscopy was found to be correlated with dark focus, but further study is needed to define the relationship.