Comparison of 4 Methods of Eye Drops for Pupil Dilation in Diabetic Patients

Diabetic patients participating in this study will be randomed to get 1 drop or 3 drops of dilating drug. And one eye of each patient will be randomed to get 1 drop of anesthetics, while the other eye does not. So there are 4 groups of eyes in the study. Group 1 receive 1 drop of dilating drug. Group 2 receive 1 drop of anesthetics + 1 drop of dilating drug. Group 3 receive 3 drops of dilating drug. And group 4 receive 1 drop of anesthetics + 3 drops of dilating drug. Pupil size will be measured before and after the drops.