Corneal endothelial cell count is done by –
**Core Concept**
The corneal endothelium is a single layer of cells lining the posterior surface of the cornea, playing a crucial role in maintaining corneal deturgescence. The endothelial cell count is an essential parameter in assessing the health and function of the corneal endothelium.
**Why the Correct Answer is Right**
The correct answer is obtained using a specular microscope, which is a specialized instrument that allows for the direct visualization and counting of individual endothelial cells on the corneal surface. This method provides a precise measurement of the endothelial cell density, which is expressed in cells per square millimeter (cells/mm²). The specular microscope uses a combination of light reflection and microscopy to capture high-resolution images of the endothelial cells, enabling accurate cell counting.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because ophthalmoscopy is a technique primarily used for viewing the retina and posterior segment of the eye, not for assessing the corneal endothelium.
**Option B:** This option is incorrect because slit-lamp biomicroscopy is a valuable tool for examining the anterior segment of the eye, but it is not capable of providing a direct count of endothelial cells.
**Option C:** This option is incorrect because pachymetry is a technique used to measure the thickness of the cornea, not the endothelial cell count.
**Clinical Pearl / High-Yield Fact**
The endothelial cell count is an important prognostic indicator for corneal transplant success, with lower cell counts associated with increased risk of graft failure.
**Correct Answer: B. Slit-lamp biomicroscopy.**