The causes of macular edema are numerous and different causes may be inter-related. It is commonly associated with diabetes. Chronic or uncontrolled diabetes type 2 can affect peripheral blood vessels including those of the retina which may leak fluid, blood and occasionally fats into the retina causing it to swell.
Visual C++. Visual C++ is known as a native development language, as it talks directly to the hardware for the Windows Mobile device, with no intervening layers (unlike Visual C#, for example). Programming using C++ can be challenging, as it is not a trivial language to learn.
Relationship to the C-Language API. The single characteristic that sets the Microsoft Foundation Class Library apart from other class libraries for Windows is the very close mapping to the Windows API written in the C language. Further, you can generally mix calls to the class library freely with direct calls to the Windows API.