Final answer:
Blood vessels supply necessary nutrition to many parts of the eye but not all layers, as the cornea is avascular and gets oxygen from the air.
Step-by-step explanation:
The statement that 'Blood vessels supply nutrition to all eye layers' is not entirely accurate. While blood vessels do supply nutrition to many parts of the eye, the cornea, one of the eye's layers, does not have blood vessels and instead gets its oxygen directly from the air through tears. The choroid layer, which is highly vascularized, supplies blood primarily to the outer retina. The inner layer of the retina, by contrast, is nourished by the retinal blood vessels that arise from the ophthalmic artery, a branch of the internal carotid artery.
Therefore, the choroid and retinal blood vessels are crucial in providing nutrition to the eye, but not all layers of the eye are directly supplied by blood vessels, given the avascular nature of the cornea.