Certified Paraoptometric (CPO) Practice Exam 2025

What part of the eye does the choroid primarily nourish?

1. Iris

2. Cornea

3. Retina

4. Lens

The correct answer is: Retina

The choroid is a layer of the eye located between the retina and the sclera. Its primary function is to provide nourishment to the retina, which is crucial for the health and function of photoreceptor cells responsible for vision. The choroid contains a rich supply of blood vessels that facilitate this nutritional support, ensuring that the retina receives the necessary oxygen and nutrients to function effectively. The other options listed—iris, cornea, and lens—are not primarily nourished by the choroid. While the iris does receive some blood supply, it is primarily served by its own separate vascular system. The cornea is avascular (lacking blood vessels) and obtains nutrients from the tear film and aqueous humor. The lens also does not rely on the choroid for nourishment; instead, it receives nutrients from the surrounding aqueous humor. Hence, the choroid's role in supporting the retina makes it the correct answer.