**Core Concept**
The gold standard to measure angles of the eye is a critical parameter in assessing glaucoma and other ocular conditions. The measurement involves assessing the angle between the iris and the cornea, which can provide valuable information about the risk of glaucoma and other eye conditions. This measurement is essential for diagnosing and managing various ocular diseases.

**Why the Correct Answer is Right**
The gold standard to measure angles of the eye is gonioscopy. Gonioscopy involves the use of a specialized lens or mirror to visualize the angle between the iris and the cornea. This technique allows for a direct assessment of the angle, which is essential for diagnosing glaucoma and other ocular conditions. Gonioscopy also enables the measurement of the depth and configuration of the angle, which can provide valuable information about the risk of glaucoma.

**Why Each Wrong Option is Incorrect**
**Option A:** **Amsler grid** is a tool used to detect macular degeneration and other retinal disorders, but it is not used to measure angles of the eye.

**Option B:** **Fundus examination** is a technique used to visualize the interior of the eye, including the retina and optic disc, but it is not used to measure angles of the eye.

**Option C:** **Slit-lamp examination** is a technique used to examine the anterior segment of the eye, including the cornea and iris, but it is not the gold standard for measuring angles of the eye.

**Clinical Pearl / High-Yield Fact**
Gonioscopy is essential for diagnosing glaucoma, and the results can be classified into four types: open angle, closed angle, shallow angle, and occludable angle. A shallow or occludable angle is associated with an increased risk of glaucoma.

**Correct Answer:** C. Gonioscopy.