This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Tonometer with variation in application surface 
Select and explain. 
A. Mackey Marg tonometer, B. Rebound tonometer, C. Dreger's tonometer, D. Maklakov tonometer
D: Maklakov tonometer
Answer: D: Maklakov tonometer 
Explanation: Ans. d. Maklakov tonometer Indentation tonometry Indentation tonometry was devised by SchiotzQ. Because of its simplicity, reliability, low price and relative accuracy, it is the most widely used tonometer in the world. For repeated use in multiple patients it can be sterilized by dipping the footplate in ether, absolute alcohol, acetone or by heating the footplate in the flame of spirit. The greatest accuracy is attained if the deflection of lever is between 3-4. Its main disadvantage is that it gives a false reading when used in eyes with abnormal scleral rigidity') False low level of 10P are obtained in eyes with low scleral rigidityQ seen in high myopes and following ocular surgery Applanation tonometry The concept of Applanation tonometry was introduced by GoldmannQ is 1954. It is best on lmbe-Fick lawQ. Currently, it is the most popular and accurate tonometerQ