'Early' is a subjective term, and can mean different things to different people.
The real question is: is the cataract affecting your vision, and by how much?
A very early 'cataract' may not affect vision at all. In this case, the only possible benefit of doing the operation is the possibility of refractive correction-the procedure becomes like LASIK and only aims to reduce spectacle power. In this case, there is no difference between wearing glasses/contact lenses and having the surgery, for older people. For younger people less than 40 years of age, doing this kind of surgery (lens replacement) may even feel like a worse situation because they immediately get full presbyopia.
The more a cataract is affecting vision, the greater the visual improvement that will be perceived after surgery and the better the risk versus benefit ratio. You could say it is a good thing to delay surgery until a cataract reaches such a density that the visual blurring it causes starts to bother the patient.
So let's assume another scenario, where the cataract is already affecting vision significantly and the patient is pondering whether to do it now or 6 months later.
The situation becomes clearer if you think of this analogy: Someone has a pair of glasses with badly scratched and hazy lenses. What happens if he changes his glasses now, versus 6 months later?
So if someone already has a significant cataract, getting it done earlier will give faster recovery of vision, and avoid the frustration of having to put up with blurry vision for some arbitrary period of time. Or you could also look at it this way-you are going to go through the process of surgery anyway, so why put up with the blurriness any longer than you have to?
For certain groups of people, such as those with weak corneal endothelial cells, it may also be better to do it earlier rather than later because a milder, softer cataract requires less ultrasound energy to emulsify, and so may help these people preserve the remaining endothelial cells better. To some extent, this is also true of other people without endothelial problems, however, it would take a pretty dense/hard cataract to trouble most surgeons in people with normal corneas.
Also, an extremely dense, hypermature cataract could give rise to other problems like inflammation or rises in eye pressure, though in Singapore it is very rare to encounter cases like these nowadays.
