Ophthalmology All of the following ocular structures are derived embryologically from the neuroectoderm except: A Epithelial layers of ciliary body and iris B Sphincter and dilator pupillae muscles C Optic nerve D Optic nerve sheaths 💡 Explanation All of the following ocular structures are derived embryologically from the neuroectoderm except: ✓ Correct Answer: D. Optic nerve sheaths