As far as I know, blindness or disability are not exceptions to the penalty for underpayment. However, anyone who receives a penalty notice may apply for a waiver for reasonable cause, and a penalty can also be waived if it is your first time being assessed a penalty.
https://www.irs.gov/payments/penalty-relief
blindness and disability are not the same thing on income taxes. Being disabled means that a person is unable to perform substantial gainful work. Many people who meet a medical definition of disability are nevertheless able to perform gainful work, and don’t qualify as disabled for income tax purposes.
