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 summarize, C# programming language can be used to build Windows app using the .NET platform, and can also be used to build Linux app using the Mono platform. It cannot be used to make an Android app, but with persistence, in theory, you can wrap it around the Android NDK framework.