Anterior segment growth and peripheral neural pathways in chick

Area of Science:

• Ophthalmology
• Neuroscience
• Developmental Biology

Background:

• Corneal expansion and anterior segment growth are influenced by various factors, including light exposure.
• The role of peripheral nerve pathways in ocular development under different lighting conditions remains incompletely understood.

Purpose of the Study:

• To investigate the necessity of peripheral nerve pathways for corneal expansion and anterior segment growth under a 12-hour light:dark cycle.
• To determine if peripheral nerves inhibit corneal expansion under constant light rearing.

Main Methods:

• White Leghorn chicks underwent unilateral ciliary ganglionectomy, cranial cervical ganglionectomy, or ophthalmic nerve section.
• Chicks were reared under a 12-hour light:dark cycle or constant light for two weeks.
• Corneal dimensions, refractometry, and ocular measurements were performed postoperatively.

Main Results:

• Selective denervations showed minimal impact on corneal expansion and anterior segment development under both lighting conditions.
• Ophthalmic nerve section partially reversed the inhibition of equatorial expansion of the vitreous chamber under constant light.

Conclusions:

• Ciliary, sympathetic, and ophthalmic nerve pathways are not required for normal corneal development or light-induced growth inhibition.
• Ocular sensory innervation may play a role in regulating vitreous cavity shape.