It was probably Rolex that pioneered the use of a magnification lens on a watch’s crystal over the date to enhance the wearer’s ability to see the date. They were most likely to first to use this technique although it is unclear whether they invented the concept. Since Rolex starting using magnifier lenses, it has been a controversial watch feature. While most people don’t need the magnification lens (sometimes called a “cyclops”) to read the date, it is a nice addition to have when you want to know the date at a glance. And for some people, the date is just too small to be read without squinting.
Rolex put the magnifier lens on the Submariner (not Sea Dweller model) watches and the Datejust models (among other Rolex watch models). The placement of the date and magnifier was specifically chosen where it is, because if wearing a watch on your left hand, it was the first part of the watch that emerged from your sleeve, allowing quick reference to the date. Virtually all the Rolex clone models started to copy this design feature as it was an integral characteristic of the watches.
Magnifier lenses are not without their drawbacks. Many people do not like them for two reasons. First, is that they tend to attract scratches and blemishes. Being raised up from the otherwise flat crystal, the lens bump simply had more opportunity to rub against things. Second, lots of people simply do not like them from an aesthetic point of view. It is true that the magnifier lens can detract from the symmetry of a watch, and look odd while looking at the watch’s side profile.
In response to this, lots of people started to have magnifier lens removed through various types of customization, and watch makers ended up making models with and without the magnifier lenses. So consumers had two options, either go with a cleaner looks or have a date indicator that is easier to see.
The next step in the evolution of the date window magnifier was very clever, and almost seems obvious given the result. Watch makers took the magnifier lens and placed it upside down on the bottom of the crystal, as opposed to on the top. By reversing the lens, to magnify in this new direction, the same effect is achieved without the bump on top of the crystal. You can see this feature on some of the more expensive watches. A few notable ones are the Zenith Defy series, the Louis Vuitton Tambour line, and the Chopard Mille Miglia line of watch models. This upside down magnifier lens feature is not limited to these models, and should be found on a number of newer watches. As time goes on, these new types of lenses are sure to appear on less expensive models.
To achieve this upside down lens effect, there must be enough clearance between the face of the watch, and the crystal. With the trend in watches being larger in size, this is often not an issue, and the upside down lens is actually a bit smaller than would be needed on top of the crystal. Needless to say, this feature is very clever, and works wonderfully in providing the best of both worlds to those of us who want a clean looking watch that is visually convenient.