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.
Giving C# a go. As an iOS developer, you're accustomed to Objective-C and Swift. The closest Microsoft programming language to both is C#. For most developers and most apps, we think C# is the easiest and fastest language to learn and use, so this article's info and walkthroughs focus on that language.