Generally speaking, you can wait as long as you want to have cataract surgery. It is exceptionally rare that a cataract operation needs to be done quickly. You have the surgery done when you decide you need to see better and glasses don’t work as well as they used to.
In truth, you probably DO have some degree of cataract in your right eye -it is just not as bad as the cataract in the other eye. Cataracts rarely develop in parallel -one side leads the way.
A better way to think about cataracts is not as a “thing” you get, but as the process of aging in the eye’s natural lens. The natural lens progressively hardens, starting in our 20s, making it progressively more difficult to see up close without help. This presbyopia is actually the earliest symptom of what will come to be called “cataract.” As the natural lens reaches its later stages of hardening, it also begins to discolor. This discoloration further affects vision, albeit very slowly. It is only when this hardened, discolored lens starts to cloud up that the vision becomes bad enough for most people to consider having it removed and replaced with an artificial intraocular lens.
The trend, however, is for earlier surgical treatment of cataracts than in the past. The surgery is quicker, safer, and more predictable. You can also get rid of your nearsightedness and astigmatism at the same time. And the newest lens implant technology can even restore much of your near vision as well. All of these later developments have helped increase the numbers of cataract/lens implant procedures being done.