Keratometer is used for ?
**Core Concept**
The **keratometer** is an ophthalmological instrument used to measure the curvature of the **cornea**, which is crucial for assessing the **refractive power** of the eye. This measurement is essential in ophthalmology for calculating the power of intraocular lens implants and for diagnosing certain corneal disorders.
**Why the Correct Answer is Right**
The correct answer is related to the measurement of corneal curvature, which is vital for understanding the eye's refractive status. The keratometer works by reflecting light off the cornea and measuring the distance between the reflection points, allowing for the calculation of the corneal curvature.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because it does not relate to the primary function of a keratometer.
**Option B:** Similarly, this option is not relevant to the use of a keratometer in ophthalmology.
**Option C:** This choice is also incorrect as it does not pertain to the measurement of corneal curvature.
**Option D:** This option is incorrect because, although related to ophthalmology, it is not the primary use of a keratometer.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the keratometer measures the corneal curvature in the central 3-4 mm of the cornea, which corresponds to the **optical zone** of the cornea. This measurement is critical for calculating intraocular lens power.
**Correct Answer:** D. Measuring corneal curvature.