Anatomy of the eye from the view of Ibn Al-Haitham (965-1039). The founder of modern optics.

Ibn Al-Haitham (known as Alhazen in Latin [965 Basra, Iraq-1039, Cairo, Egypt]) was a scientist who played an important role in the middle age Islam world. He wrote many books and novels, but only 90 of them are known. His main book Kitab al-Manazir was translated into Western languages in the late twelfth century, and in the early thirteenth century. In this book, he formulated many hypotheses on optical science. The book, which is also known as Optic treasure (opticae thesaurus), affected many famous Western scientists. He became an authority until the seventeenth century in the Eastern and Western countries. Roger Bacon (1212-1294), who made radical changes in the Western optical traditions, reconfirmed Ibn Al-Haitham's findings. Ibn al-Haitham began his book Kitab al-Manazir with the anatomy and physiology of the eye. He specifically described cornea, humor aqueous, lens, and corpus vitreum. He examined the effect of light on seeing. He caused changes in the prevailing ideas of his age, and suggested that light came from objects, not from the eye. He provided information regarding the optic nerve, retina, iris, and conjunctiva. He showed the system of the eye as a dioptric, and the relations between the parts of the eye. It is understood that he mastered all knowledge on the structure of the eye in his century. The best proof of this is the eye picture that he drew.

Morphometric analysis of embryonic rat trigeminal neurons treated with different neurotrophins.

In whole-mount explant cultures of the trigeminal ganglion (TG) with intact peripheral and brainstem targets, exogenous application of nerve growth factor (NGF) and neurotrophin-3 (NT-3) leads to elongation and precocious arborization of embryonic trigeminal axons, respectively. In addition, neurotrophins play a major role in survival and differentiation of distinct classes of TG neurons. In the present study, we conducted morphometric analyses of trigeminal neurons exposed to exogenous NGF or NT-3 in whole-mount explant cultures. Explants dissected from embryonic day (E) 13 and E15 rats were cultured in the presence of serum-free medium (SFM) or in SFM supplemented with NGF or NT-3 for 3 days. TG neurons were then retrogradely labeled with lipophilic tracer DiI and their soma size distributions were compared following different treatments. The mean diameters of E13 and E15 trigeminal neurons grown in the presence of NT-3 were similar to those grown in SFM. On the other hand, in cultures supplemented with NGF, the mean diameters of neurons were larger at E13, but smaller at E15. Double immunolabeling with TrkA and TrkC antibodies confirmed the presence of large-diameter TrkA-positive neurons in E13 TG, but not in E15 TG. At both ages, other large-diameter neurons expressed only TrkC. These results show that exposure to NGF leads to phenotypic changes in TrkA-expressing trigeminal neurons at early embryonic development, but selective survival of small diameter neurons at later ages.