**Core Concept**
Choroidal neovascularization (CNV) is a process where new blood vessels grow from the choroid layer of the eye into the overlying retinal pigment epithelium (RPE) or Bruch's membrane. This pathological process is often associated with age-related macular degeneration (AMD), trauma, and other ocular diseases.

**Why the Correct Answer is Right**
Choroidal neovascularization occurs due to the breakdown of the blood-retinal barrier, leading to the invasion of new blood vessels into the subretinal space. This process is mediated by the release of angiogenic factors, such as vascular endothelial growth factor (VEGF), which stimulate the growth of new vessels. The formation of new blood vessels in the subretinal space can lead to the development of subretinal hemorrhages, fluid accumulation, and vision loss.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because choroidal vascularization is not a characteristic feature of diabetic retinopathy, which is primarily associated with retinal microvascular changes such as microaneurysms and retinal hemorrhages.
* **Option B:** This option is incorrect because glaucoma is a group of eye conditions that are primarily associated with optic nerve damage and increased intraocular pressure, rather than choroidal vascularization.
* **Option C:** This option is incorrect because cataract is a condition characterized by the clouding of the lens in the eye, which does not directly involve choroidal vascularization.

**Clinical Pearl / High-Yield Fact**
Choroidal neovascularization is a significant cause of vision loss in patients with age-related macular degeneration, and treatment with anti-VEGF agents has become a standard approach to managing this condition.

**Correct Answer: D.**