It is no secret that the numerous RPGs out there are not disability friendly when it comes to certain environments, terrains, or situations. Even though a lot more can be done to remedy this problem, some game designers (individuals and companies) are starting to develop ways in which characters who do have disabilities can more fully interact with the world around them.
If your character does have a physical, mental, or medical disability, it is the player's responsibility to truthfully explore how that character may have faced and dealt with this unique challenge in their life.
Did they develop a new mobility aid (e.g., combat wheelchair) to help them get around on their own?
Did they invent a new optical device which allows them to see or a new implant which allows them to hear?
Did they create a new form of meditation which they have utilized to help them more readily resolve their crippling anxiety or depression?
It is important to understand that not every character will be able to find a way to resolve the challenges that disabilities may bring up, but it is important that you as a player should be sensitive to the real world challenges of those with disabilities (seen & unseen). Endeavor to portray the character truthfully and not as a caricature or parody of someone with a disability.
Don't cheat your character by popping a pill or utilizing a spell which immediately removes the disability. Work with your DM/GM to find a way to incorporate your character's disability into the game and how that disability might help or hinder your character and their team. Some disabilities may even lead to your fellow adventurers working together to find a way to make your character as strong, or even stronger, through teamwork.