Medieval ophthalmological manuals, such as those mentioned above, frequently prescribe wet and dry collyria (Arabic, kuḥl or šiyāf) for the treatment of various eye disorders. Both types of collyria were stored as tablets; the dry form of the drug was ground and blown directly into the eye, whereas the wet kind was softened with water before application. In his Ten Treatises on the Eye, Ḥunayn recommends the use of rainwater for the preparation of wet collyria on account of its purity, and he instructs the reader to add it to the ground tablet until the medicine acquires the consistency of pigeon dung (Meyerhof 1928, p. 129, ll. 14–25 (English translation), p. 196, ll. 8–14 (Arabic text)). Some of the ingredients listed in wet collyria recipes include wine, honey, balsam oil, fennel juice, and asafoetida. Animal products were also utilised for different ophthalmic drugs. For example, on the authority of Paul of Aegina (fl. c. 630), Ḥunayn and other Arabic medical writers advise patients suffering from night-blindness (aʿšā) to eat roasted goat-liver and to bathe their eyes in the bloody roasting juices (Meyerhof 1928, p. 121, l. 1–4 (English translation), p. 189, ll. 1–2 (Arabic text); see also Pormann 2004, 193–5). Furthermore, while the liver is roasting, the attending doctor should order the patient to open their eyes so that the smoke from the cooking offal may enter them...
Right: Doctors working in the medieval Islamicate world engaged critically with the material concerning ophthalmology that was inherited from Graeco- Roman antiquity. This field of medicine was called kuḥl in Arabi. This 13th century manuscript dipicts instruments for eye surgery as displayed in a copy of al-Ḥalabī’s Sufficient Book on Ophthalmology (al-Kāfī fī l-kuḥl).