Illustration from Ming Chinese ophthalmology text, Ms copy

Illustration of slippery nebula (hua yi), an 'internal eye disease' (neizhang), from Michuan yanke 72 zheng quanshu (Secretly Transmitted Compendium of 72 Ophthalmic Diseases) by Yuan Xueyuan (Ming period, 1368-1644). This book uses a combination of text and pictures to explain the symptoms, causes and treatment of 72 different eye conditions, 24 of which are described as internal.

Picture heading: Slippery nebula (hua yi), internal eye disease (neizhang)