Are 450-485 cc implants too big? (Photo)

Patients often think in terms of cup size when considering augmentation. Unfortunately, devices are sized in terms of milliliters (cc) of volume. This can lead to some confusion when sizing. Additionally, it is important to remember that cup size itself is not standardized with variations from one manufacturer to another. Unfortunately, as many women can attest their cup size in an industry leader such as VS is not necessarily transferable to another brand.
Another point which is often under appreciated is that of anatomy and starting point. Any implant will add volume to the volume which is already present. The implant is additive. A particular volume will not necessarily confer the same cup size to different patients (often times it will not even confer the same cup size to different breasts in the same individual...remember they are "sisters" not "twins"). 
A general rule of thumb is that 125cc can represent somewhere between 1/2 to a full cup size increase. Smaller volume differentials (25-50cc) are typically less consequential representing a volume change of less than a shot glass. However, I have found these numbers, at least anecdotally, to be of little help. Patients often present with notions/goals which do not correlate with these sorts of sterile volumetric assessments.
When sizing patients, there are a number of useful tools including:
-3D imaging (has the added benefit of offering a volumetric analysis of the pre-operative breast)
-Breast sizers (rice bags)
-Goal photos
I also recommend that patients commit to a particular look rather than a cup size. Once a patient settles on a look that pleases them the overall cup size increase becomes less relevant.The key to obtaining a natural result is to stay within the parameters defined by your BWD. This will ensure that you avoid the dreaded "fake" look. 
"Too big" is, to a certain extent a relative question. As long as you have been appropriately sized (meaning the implant dimensions fit within your BWD), 450 cc may be reasonable. Based on your photos alone, I would lean smaller. Without measurements, it is difficult to offer more concrete advice. 
As always, discuss your concerns with a board certified plastic surgeon (ABPS).

Thank you for your question and photograph.  Breast implant selection is an exciting, but stressful part of the breast augmentation process as there are so many choices. Unfortunately it is impossible to recommend the best implant style, size or shape without an in-person examination that allows for the measurement of key breast parameters, as well as permits an in-depth discussion as to your desired goals and outcome. I think trying on different sizers will give you a better visual representation as to what they would look like.  Best wishes!

I would say, without hesitation, no!  That size seems very nice for your height and weight.  Most patients wish they were bigger after the surgery so dont be scared.  Also, if the doctor as the Vectra 3D imaging machine, I would strongly suggest you use it.  Good luck!