This study aimed to determine the power-law exponents (D) of emphysema hole-size distributions as a reliable index and investigate their robustness to breath-hold-level variations. The correlations between D and clinical parameters for COPD were examined and compared to a conventional emphysema index (EI%). 100 COPD patients underwent CT scans at full inspiration and expiration. D showed strong agreement between breath-hold levels, while EI% did not. D exhibited significant correlations with airflow limitation, diffusion capacity, exercise capacity, and quality of life. The transfer of this research idea to Coreline Soft for commercialization highlights its potential as a valuable tool for assessing emphysema severity, minimizing the impact of breath-hold variations.