This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cornea and sclera, Subject name: Ophthalmology
Corneal endothelium was seen by 
Select and explain. 
A. Pachymeter, B. Keratometer, C. Tonometer, D. Slit lamp bio-microscope
D: Slit lamp bio-microscope
Answer: D: Slit lamp bio-microscope 
Explanation: (Refer: AK Khurana Comprehensive Ophthalmology, 6th edition, pg no. 95 - 96)Corneal endothelium:It consists of single layer of polygonal (mainly hexagonal cells)They are visualized by slit lamp bio-microscope and appear like a mosaicThe cell density is 30000 cells/mm2 in young adults and decreases with ageThese cells contain active pump mechanism