Problemata (Problems)

...moving factors for those suffering from eye inflammation ophthalmia: a general term for redness, swelling, or infection of the eyes. Some take their origin from within; but in the case of external factors, they strike from without.

Why some of those who have suffered from eye inflammation seem to have sharper vision

It is clear that just as those substances which induce tearing and eye-salves kollyria: ancient medicinal pastes or washes applied to the eye are called vision-sharpening oxyderkika: medications believed to improve the keenness of sight because of the resulting tearing and the subsequent cleansing katharsis: a medical purification or purging of harmful fluids, allowing those who use them to see more sharply—so too it happens to those who have shed tears due to eye inflammation. Dimness of vision occurs when a certain thicker matter rests upon the eye; but once a cleansing has taken place, vision is restored.

Why those about to suffer from a suffusion of the eye seem to see gnats, or flies, and ants, and why such a phenomenon naturally follows

The term "suffusion" (original: "ὑποχύσεσθαι") refers to the ancient medical understanding of cataracts, where it was believed a fluid "poured down" and solidified behind the pupil, blocking sight.

It is clear that whatever cause this condition takes, such things necessarily fall under the sight. As soon as the fluid begins to thicken original: "πήγνυσθαι" (pēgnysthai) — to curdle or solidify; here referring to the humors of the eye becoming opaque, it becomes perceptible to the sensory ray The author refers to the ancient "extramission" theory of vision, where the eye was thought to emit a physical ray to "touch" objects....