Axial length of eye for cataract surgery is measured by which of the following?
**Core Concept**
The measurement of axial length of the eye is crucial in cataract surgery, particularly for calculating the power of intraocular lenses (IOLs) to achieve correct vision post-operatively. This measurement is essential in preventing complications such as myopia or hyperopia.
**Why the Correct Answer is Right**
The correct answer is **Achimer's IOLMaster**. This device uses partial coherence interferometry to measure the axial length of the eye with high accuracy. It calculates the distance from the cornea to the retina, taking into account the curvature of the cornea and the position of the retina. This information is vital for selecting the correct power of IOL for implantation.
**Why Each Wrong Option is Incorrect**
**Option B:** Ultrasound biomicroscopy (UBM) is an imaging technique that uses high-frequency ultrasound to visualize the anterior segment of the eye. While it can provide detailed images of the eye's structures, it is not designed for measuring axial length.
**Option C:** Optical coherence tomography (OCT) is a non-invasive imaging technique that uses low-coherence interferometry to produce high-resolution images of the eye's internal structures. While OCT can measure retinal thickness and other parameters, it is not the primary tool for measuring axial length.
**Clinical Pearl / High-Yield Fact**
Remember that accurate measurement of axial length is crucial in cataract surgery to prevent post-operative complications. The IOLMaster is a reliable and widely used device for this purpose.
**Correct Answer:** A. Achimer's IOLMaster.