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.
To install C#, for the moment anyway, you don't need to purchase a thing. You just need to get your hands on the Microsoft .Net Framework. C# is a language that comes with the Microsoft .Net (pronounced DOT-NET) Framework. The .Net Framework is an environment that permits .Net programs to run. C# is just one of many programming languages supported by the .Net framework (it even includes COBOL).