Final answer:
In the retina, arteries and arterioles have thicker walls but smaller lumens than veins and venules, with arteries designed to withstand higher blood pressure. The fovea, which provides the highest visual acuity, lacks blood vessels entirely.
Step-by-step explanation:
In regard to vessels in the retina, the arteries and arterioles have thicker walls than veins and venules. However, the arteries have smaller lumens compared to veins. This structural difference is because arteries are closer to the heart and need to withstand higher blood pressure. Despite the thicker walls, arterial lumens have a more rounded appearance and are smaller in diameter, aiding in maintaining blood pressure. Conversely, veins, which carry blood back to the heart at a lower pressure, have larger lumens and thinner walls.
In the retina specifically, the fovea is the area with the highest visual acuity and lacks blood vessels, resulting in the least amount of light absorption by non-photoreceptor structures. Overall, arteries, including retinal arteries, are generally the vessels with thicker walls, while veins are larger in terms of lumen size in the retina and throughout the body.