Hunayn ibn Ishaq's Book of the Ten Treatises of the Eye (Arabic: كتاب العشر مقالات في للعين, Kitab al-Ashr Maqalat fil-Ayn) is a 9th-century theory of vision based upon the cosmological natures of pathways from the brain to the object being perceived.

As opposed to Galen's more mathematical conception of flat-like lens, Hunayn opts for a more spherical shape which allows for a larger field of vision.

[3] He describes the system behind the eyes that connects it to the brain, starting with the sclera, a thick, hard membrane which protects the inner parts of the nerves from injury.

While both the conjunctiva and cornea provide protection with minimizing hindrance to the lenses, the uvea has an extra function of concentrating the pneuma exiting out of the eye to prevent it from being dissipated by light.

After collecting in the uvea, this pneuma then travels along the medium of air, causing a transformation that conforms to the shape around it, sending this signal back to the eye.