This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy, Development and clinical examination, Subject name: Ophthalmology
Corneal thickness is measured by all Except 
Select and explain. 
A. OCT, B. Utrasonography, C. Orbscan, D. Javal Schiotz method
D: Javal Schiotz method
Answer: D: Javal Schiotz method 
Explanation: The Javal-Schiotz model keratometer consists of two illuminated 'mires' (A and B) fixed on a rotatable circular arc (C) and a viewing telescope T. The double images (aa1 and bb1) of the mires (A and B) are formed on the cornea. Keratometry readings are obtained by coinciding the images a1 and b. The readings are noted first in the horizontal meridian and then the arc is rotated by 90o and the readings are noted in the veical meridian. Reference : A K KHURANA Comprehensive Ophthalmology; edition 4, page-554