**Core Concept**
Macular edema is a condition characterized by the accumulation of fluid in the macula, the central part of the retina responsible for central vision. This can lead to blurred vision, blind spots, or distorted vision. The most common causes of macular edema are related to inflammation, injury, or vascular changes in the eye.

**Why the Correct Answer is Right**
Cataract surgery is a common cause of macular edema due to the manipulation of the eye during surgery, which can lead to inflammation and fluid leakage from retinal capillaries. The surgical procedure involves the creation of a wound in the eye, which can cause trauma to the retina and lead to macular edema. Additionally, the use of intraocular lenses and other surgical instruments can also contribute to the development of macular edema.

**Why Each Wrong Option is Incorrect**
**Option A:** Secondary glaucoma is a condition characterized by increased intraocular pressure, which can lead to optic nerve damage and vision loss. However, it is not a direct cause of macular edema. The increased pressure can lead to ischemia and damage to the retina, but it is not the most common cause of macular edema.

**Option C:** Retinitis pigmentosa is a group of genetic disorders that affect the retina and lead to progressive vision loss. It is not a cause of macular edema, but rather a separate condition that affects the retina.

**Option D:** Uveitis is an inflammatory condition that affects the uvea, the middle layer of the eye. While uveitis can cause macular edema, it is not the most common cause.

**Clinical Pearl / High-Yield Fact**
It is essential to note that macular edema can occur after any ocular surgery, including cataract surgery, LASIK, and vitreoretinal surgery. This highlights the importance of monitoring patients for postoperative complications and managing them promptly to prevent long-term vision loss.

**✓ Correct Answer: B. Cataract surgery. Cataract surgery is a common cause of macular edema due to the manipulation of the eye during surgery, which can lead to inflammation and fluid leakage from retinal capillaries.**