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
To check power of IOL, which formula is commonly used: March 2010 
Select and explain. 
A. Hoffer formula, B. Holladay formula, C. SRK formula, D. None of the above
C: SRK formula
Answer: C: SRK formula 
Explanation: Ans. C: SRK formula Sander's-Retzlaff-Kraff (SRK) formula is the widely used formula for calculating the power of the intraocular lens to be implanted. It is based on a statistical correlation between calculated and observed refractive error after intraocular implantation.