Its been long since my last message.
I have had 2months of stress, work, study and exams. Finally its over . Well only for another 2 months that is then the process repeats itself.
Anyhow I have couple of questions: 1)how is the blank size aka minimum size uncut calculated for varifocals. Is it the same as single vision lenses/bifocals.
When examining patients for the eye test I always have difficulty measuring the back vertex distance. By definition its the ditance from corneal apex to the backmost trial lens in the trial frame but when it comes to measuring with accuracy I fail. Is it measured with both examiner eyes opened with examiner standing to the side of the patients face. How is it measured for trial frames.
What exactly is the purpose of prisms at the prism checking point in varifocals?