While the ADA regulations don't mention websites, the U.S. Department of Justice frequently cites recommendations such as the Web Content Accessibility Guidelines (WCAG) 2.0 and 2.1 created by the World Wide Web Consortium (W3C), an international group that helps create and promote web standards. The WCAG highlight different criteria for making websites more accessible to people with disabilities, such as including captions for audio content and using high-contrast color schemes.

First, it is difficult to objectively categorize health problems as "major" and "minor." Many people live with what are called "invisible disabilities." These are problems that are not immediately obvious to an observer because the person who lives with them may not require an apparatus such as a wheelchair or cane, and he or she may not be in any visible pain. However, these health issues can create serious obstacles for the people who live with them. There are certain kinds of heart and muscle conditions that greatly limit how much a person can move about each day.
Thanks for writing. While I’m not a lawyer I believe if your physical practice is ADA exempt your web presence, as an extension of that physical business would maintain the same exemption status. If you’d like to be absolutely certain I’d confer with an ADA lawyer (email us, questions at yokoco dot com if you need a referral) but I don’t believe you have reason to worry.
ADA disabilities include both mental and physical medical conditions. A condition does not need to be severe or permanent to be a disability.[6] Equal Employment Opportunity Commission regulations provide a list of conditions that should easily be concluded to be disabilities: deafness, blindness, an intellectual disability (formerly termed mental retardation), partially or completely missing limbs or mobility impairments requiring the use of a wheelchair, autism, cancer, cerebral palsy, diabetes, epilepsy, Human Immunodeficiency Virus (HIV) infection, multiple sclerosis, muscular dystrophy, major depressive disorder, bipolar disorder, post-traumatic stress disorder, obsessive compulsive disorder, and schizophrenia.[7] Other mental or physical health conditions also may be disabilities, depending on what the individual's symptoms would be in the absence of "mitigating measures" (medication, therapy, assistive devices, or other means of restoring function), during an "active episode" of the condition (if the condition is episodic).[7]
Courts have taken essentially the following position on the issue of whether websites are places of public accommodation: Website accessibility fulfills the spirit of the ADA by lowering the barriers for people with disabilities to participate in business and commerce. As such, commercial websites need to comply with ADA regulations. Judges have reached this conclusion in several high-profile cases, such as the National Federation of the Blind’s lawsuit against the Scribd digital library. As a result of this case, Scribd agreed to redesign its website to work with screen reader software by the end of 2017.

Videos need to incorporate features that make them accessible to everyone. Provide audio descriptions of images (including changes in setting, gestures, and other details) to make videos accessible to people who are blind or have low vision. Provide text captions synchronized with the video images to make videos and audio tracks accessible to people who are deaf or hard of hearing.
An employer cannot require you to take a medical examination before you are offered a job. Following a job offer, an employer can condition the offer on your passing a required medical examination, but only if all entering employees for that job category have to take the examination. However, an employer cannot reject you because of information about your disability revealed by the medical examination, unless the reasons for rejection are job-related and necessary for the conduct of the employer's business. The employer cannot refuse to hire you because of your disability if you can perform the essential functions of the job with an accommodation.
I have a membership website teaching martial arts. It is accessible only to people who pay a monthly membership fee. I recently had a gentleman in Malta ask if I could make more than 850 videos on the site accessible to him (he is visually impaired). That is an impossible task for a one-man business. If I understand this article correctly, my site is not required to be accessible?
Many people with disabilities use assistive technology that enables them to use computers. Some assistive technology involves separate computer programs or devices, such as screen readers, text enlargement software, and computer programs that enable people to control the computer with their voice. Other assistive technology is built into computer operating systems. For example, basic accessibility features in computer operating systems enable some people with low vision to see computer displays by simply adjusting color schemes, contrast settings, and font sizes. Operating systems enable people with limited manual dexterity to move the mouse pointer using key strokes instead of a standard mouse. Many other types of assistive technology are available, and more are still being developed.
The 2014 case involving Peapod, an online grocery retailer emphasizes that being ADA compliant goes beyond your website. The settlement required Peapod to make its mobile applications accessible by March 2015 and its website accessible by September 2015. Since mobile apps are fast becoming the preferred method of online shopping, e-commerce sites must focus on app accessibility too. 
Small businesses with either $1,000,000 or less in revenue or 30 or fewer full-time employees may take a tax credit of up to $5,000 annually for the cost of providing reasonable accommodations such as sign language interpreters, readers, materials in alternative format (such as Braille or large print), the purchase of adaptive equipment, the modification of existing equipment, or the removal of architectural barriers.