Which of the following is a layer between choroid and retina?
**Core Concept**
The choroid and retina are two distinct layers in the eye that play crucial roles in vision. The choroid, a highly vascularized layer, supplies the retina with oxygen and nutrients. However, the choroid and retina are separated by a thin, pigmented layer that regulates light entry and protects the retina.
**Why the Correct Answer is Right**
The correct answer is the retinal pigment epithelium (RPE), a single layer of pigmented cells that separates the choroid from the retina. The RPE is responsible for phagocytosing shed photoreceptor outer segments, recycling retinaldehyde, and maintaining the blood-retina barrier. The RPE also contains melanin, which absorbs excess light and prevents it from entering the retina.
**Why Each Wrong Option is Incorrect**
* **Option A:** Bruch's membrane is a collagenous layer between the RPE and the choroid, but it is not the layer between the choroid and the retina.
* **Option B:** The retinal nerve fiber layer is a layer of axons that transmit visual information from the retina to the optic nerve, but it is not the layer between the choroid and the retina.
* **Option D:** The sclera is the white, outer layer of the eye that provides structural support, but it is not the layer between the choroid and the retina.
**Clinical Pearl / High-Yield Fact**
The retinal pigment epithelium is a critical layer in the eye that plays a key role in maintaining vision. Damage to the RPE can lead to conditions such as age-related macular degeneration and retinal detachment.
**Correct Answer:** C. Retinal pigment epithelium.