It's all involuntary. That doesn't sound right, however, when the eye gets dry and feels irritated, it then waters much more than usual to wash away the irritant and these tears are inefficient tears and are of little value. In '92, I went to eye drop anesthesia. Instead of injecting the anesthetic behind the eye with a needle, the anesthetic for cataract surgery became using a few eye drops on the eye and supplementing it with mild intravenous sedation. The big advantage of these two techniques is that the patient is able to leave the operating room and immediately see because there is no patch required and because of the self sealing incision, the patient may return to an active lifestyle such as tennis the day following.
Progressive lenses work by basically buffing the bifocal line into the lens so it blends.
This leaves a slow progression from the distance part of the glasses to a near part. The biggest advantage is that patients don't see the line of the bifocal and this is a cosmetic solution. The disadvantage of progressive lenses is that an entire width of a page isn't in focus at one time so in addition to moving your eye back and forth on the page, generally you must also turn your head back and forth for each line. Some patients love them. There have been major advances in cataract surgery every three to five years over the past twenty-five years.