%0 Journal Article %A A. G. Chignell %T Modern Problems in Ophthalmology %D 1977 %R 10.1136/bjo.61.11.734 %J British Journal of Ophthalmology %P 734-734 %V 61 %N 11 %U https://bjo.bmj.com/content/bjophthalmol/61/11/734.1.full.pdf