Both dramas explore the impact of the past on an individual. While MSR focuses a lot more on the romance between the two leads, the other is much more touching and heartfelt in its message.
These dramas are very different overall. But both delve into the issues which blind individuals face, and also familial bonds and such. While Hyung is more of a story of acceptance, having hope and forgiving yourself, and moving on in life, Blind is a story of realisation, suspense and closure.
In both dramas, it feels like the female lead is really underappreciated for everything she does. They also both carry similar themes (lawyers, personal issues) and have romances which, although light at a first glance, have a deeper root. If you liked Prosecutor Princess, then Divorce Lawyer In Love might be even better, as the secondary characters also have better and deeper development than in PP.