SECT. XXXI.—ON DIMNESS OF SIGHT.
In order to avoid dimness of sight, when they plunge into cold water, people ought to open their eyes wide, for thereby the strength of their eyes will be much improved. They ought also to be careful not to hurt them by reading. Let them also avoid wine that is thick and sweet, such articles of food as ascend upwards, whatever is of difficult digestion, and engenders crude and thick humours, the herb rocket, leeks, and everything whose pungency ascends upwards. Let them also avoid reclining long in a supine position, cold, winds blowing direct in the face, smoke and dust; and pour daily into the eyes an infusion prepared thus: for a month and a day, put green fennels into an earthen vessel smeared with pitch on the outside, and pour in rain water, and then taking out the fennels, keep the water laid up for use.
Commentary. This is copied from Oribasius. (Synops. v, 27.)
Rhases gives very copious and sensible directions on this subject, but many of them are the same as those given by our author. He forbids all gross and diffusible articles of food, and also thick wines. Although he cautions against reading books written in small characters, he recommends exercising the eyes by looking at large letters or pictures. He also recommends various collyria, containing antimony, tutty, calamine, camphor, and the like. (Ad Mansor. iv, 22.)