RD stands for Registered Dietitian. A registered dietitian has the appropriate knowledge and expertise and can be considered a subject matter expert in this case, hence they are likely to be a reliable source of information relating to food and nutrition.
DM is a doctor of management or medicine in some cases.
A cataract is a clouding of the lens in your eye that affects your vision. Cataracts are very common in older people, and by age 80, more than half of all Americans either have a cataract or have had cataract surgery.
