The performance of lenses made from glass elements containing defects such as bubbles, streaks, striae, etc., has been measured and an attempt made to compare the effect of the various defects. Four defective lenses and a good or control lens were used. The performance in the image plane was determined by-four different evaluation procedures. A summary evaluation showed that the lens containing striae, although the most difficult defect to detect, produced the lowest quality image.
Fred W. Rosberry, "The Performance of Lenses Made from Inhomogeneous Glasses," Appl. Opt. 4, 21-24 (1965)