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
Corneal curvature measured by ? 
Select and explain. 
A. Keratometry, B. Pachymetry, C. Gonioscopy, D. Perimetry
A: Keratometry
Answer: A: Keratometry 
Explanation: Ans. is 'a' i.e., Keratometry The `Keratometry' or `ophthalmometry' is an objective mehod of estimating the corneal astigmatism by measuring the curvature of central cornea. Gonioscopy - Biomicroscopic examination of the angle of anterior chamber. Perimetry - Procedure of estimating the extent of visual fields. Tonography - Non - invasive technique for determining the facility of aqeous outflow (C - value).