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
The Investigation To Predict The Visual Outcome After Phacosurgery is - 
Select and explain. 
A. Pachymeter, B. Potential Acuity meter, C. Lensometer, D. Topometer
B: Potential Acuity meter
Answer: B: Potential Acuity meter 
Explanation: Answer- B. Potential Acuity meterPotential acuity meters (PAMS) measure the VA that the patient is likely to achieve once there are no more opacifications of the ocular media of the eye.These clear areas are used to project a target (numbers, letters or stripes) onto the retina using a narrow light beam.PAM measurements have been shown to be especially reliable if patients with nuclear sclerotic cataracts are measured, but may be dificult if a posterior subcapsular cataract is present.