Yes, as long as providing the leave does not create an undue hardship for the employer. The Americans with Disabilities Act of 1990 (ADA) prohibits employers from discriminating against a qualified applicant or employee because of a disability in any aspect of employment. Under the ADA, employers are required to provide reasonable accommodations to the known physical or mental limitations of persons with disabilities. An accommodation is any modification or adjustment to a job or work environment that will permit a qualified individual with a disability to apply for a job, to perform a job's essential functions (i.e., fundamental duties), or to enjoy equal benefits and privileges of employment.

Generally, an individual with a disability must request a reasonable accommodation before an employer will have an obligation to provide one. Once an accommodation has been requested, an employer should engage in an interactive process to determine whether an individual has a disability that requires an accommodation and, if so, must make a reasonable effort to determine the appropriate accommodation. Accommodations vary depending on the needs of the person with the disability. In this instance, even though the six weeks of leave that are needed exceed the amount of leave provided to each employee, the employer must provide additional unpaid leave as a reasonable accommodation, absent undue hardship. The same rule would apply if the employee needs time off for treatment related to a visual disability.

Source: EEOC Guidance: Questions and Answers on Blindness and Vision Impairments and the ADA, reported in CCH Accommodating Disabilities Business Management Guide, New Developments ¶90,062.