Dr. Michael Yu Zhang, PhD, MD

Refractive disorders happen when the shape of the eye doesn't let allow someone focus very precisely. They might be myopic (nearsighted), hyperopic (farsighted), or have an astigmatism, which is a focus problem caused by the cornea. Refractive disorders can be corrected by glasses or contacts.

Glaucoma is the leading cause of blindness in the United States. It happens when fluid pressure builds up within the eye and damages the optic nerve. It is treated with medications and surgery.

Diabetic retinopathy is a common complication of diabetes. The retina is tissue at the back of the eye that is filled with numerous, tiny blood vessels. When diabetes damages these delicate blood vessels, they burst or leak, leading to blind spots and blurred vision. Diabetic retinopathy can be treated with laser therapy and surgery, but often vision cannot be restored.

Macular degeneration is common in older adults. The macula is the central part of the retina and is responsible for crisp center vision. Over time, the cells in the macula begin to die, making central vision blurry. An early symptom of macular degeneration is that straight lines appear wavy.

Cataracts happen when the clear lens in the front of the eye becomes cloudy, making things look blurry or faded. They are extremely common in older people. By age 80, more than half of all Americans will have had a cataract. In early stages, prescription glasses and magnifying lenses can help. As the cataracts get worse, surgery to replace the lens may be the best option.

More than just one of the five senses, the eyes are heavily relied upon to communicate, work, and get around every day. It's important to have regular eye exams for vision stays in good shape for years to come.

Asthma is a chronic disease where swollen, inflamed airways make it hard to breathe. It is often brought on by specific triggers. While asthma is a common condition, affecting millions of people, it can also be serious and even fatal in severe cases. Treatment involves avoiding triggers and using inhaled corticosteroid medications.

COPD, or Chronic Obstructive Pulmonary Disease, is the name given to two illnesses that both cause difficulty breathing: emphysema and chronic bronchitis. In emphysema, the air sacs of the lungs become damaged, while with bronchitis they become clogged with mucus. COPD is the fourth leading cause of death in the United States. It is almost always caused by breathing irritants into the lungs, such as smoking or heavy pollution.

Pneumonia is a lung infection that can be caused by bacteria, a virus, or fungi. Most healthy people recover from pneumonia in a week or two, but for some people pneumonia can be fatal. There are treatments available for pneumonia, but the best treatment is to prevent getting sick in the first place. People who are at risk should make sure they get a flu shot every year. There is also a vaccine available for the type of bacteria that causes pneumonia.

Lung cancer occurs when abnormal cells inside the lung grow into a tumor, destroying healthy tissue. Because it is so difficult to detect lung cancer in early stages when it has few symptoms, it is the deadliest form of cancer, responsible for the most cancer deaths both in the U.S. and worldwide. Most lung cancer is caused by exposure to tobacco smoke, but between 10-15% of cases are not linked to smoking.

Some problems with the lungs are minor and are not cause for concern. However if symptoms have lasted for a month or more, even if they are minor, it is worth checking with a healthcare professional. A cough, shortness of breath, or excess mucus production that lingers for weeks are all worth getting looked at.