Rasulullah صلی اللہ علیه وسلم has mentioned:
Whoever sees a person in any calamity and recites the following Dua will be saved from that calamity for his entire life:
الْحَمْدُ لِلّهِ الَّذِيْ عَافَانِيْ مِمَّا ابْتَلَاكَ بِهِ وَفَضَّلَنِيْ عَلَى كَثِيْرٍ مِمَّنْ خَلَقَ تَفْضِيْلًا
All praise is due to Allah who has granted me complete ease from that which He has tested you with, and He has favoured me immensely over many of His creation
In another narration it is mentioned that the difficulty will not afflict him. (Tirmizi #3431/3432)
This calamity can refer to a physical one like sickness, diseases, blindness, being paralysed, leprosy etc. It can also refer to a spiritual one like sin, oppression, innovation and disbelief. (Tuhfatul Almaee v.8 pg.101)