Are you having back pain with any of the following?

  • Severe pain, weakness or tingling in your leg(s).
  • Difficulty stopping urination or loss of control of bladder or bowels.
  • Unexplained fever, nausea or vomiting.
  • A history of cancer or unexplained weight loss.

We understand that you are experiencing one or more of the health issues that might be impacting your back pain.

We recommend that you discuss these health issues with your doctor before proceeding with this program.

Once you are cleared by your doctor to do this program, we hope it helps you find relief from your back pain.

Provider photo for Eun-Ha Park

Eun-Ha Park, MD


Welcome to My Doctor Online, a website my colleagues and I developed to make it easier for you to take care of your healthcare needs. On this site you will find answers to many of your questions about my clinical practice. Also included are several online features that will allow you to e-mail me, check your laboratory results and refill prescriptions. If you are a patient who sees me regularly, you can reach my office directly at 650-301-5807

My Offices

Daly City Medical Offices
Appt/Advice: 650-301-5800

See all office information »

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Most people experience floaters and flashing lights in their visual field sometime in their lives. They commonly occur as part of the normal aging process, and most of the time they are harmless. The sudden onset of persistent and increasing numbers of floaters or flashing lights might indicate a retinal condition which should be evaluated promptly to keep your eyes healthy.



Floaters are small specks or particles floating inside the eye which may take on a variety of shapes and sizes. They look like gnats, threads, dots, circles, lines or cobwebs in your field of vision. They drift about; they seem to move as your eyes move and then dart away when you try to focus on them. They can become apparent when you look at something bright, such as white paper or a blue sky. They become bothersome when they become numerous or more prominent. Floaters are more likely to develop as we age and are more common in people who are very nearsighted, have diabetes, or who have had eye surgery.

Flashing lights

Flashing lights, or flashes, may appear as either quick or long bursts of light that go on and off in your eye or seem to be off to one side of your field of vision. You may have experienced this same sensation if you have ever been hit in the eye and seen "stars." Flashes are most commonly seen when looking at a low-lit background or in total darkness. They tend to occur in one eye at a time and persist even when the eye is closed. The flashes of light can appear off and on for several weeks or months.


Most of the time, floaters and flashes do not indicate a serious eye problem. However flashes that occur suddenly along with many new floaters in the eye, could be symptoms of a retinal tear or retinal detachment. If you experience either of these symptoms and/or an area in your field of vision seems to be blocked or blacked out, call our offices and request an urgent appointment. If you have a decrease in vision or obstruction in your peripheral vision, you may be advised to go directly to the Emergency Department if you are calling after regular clinic hours or on a weekend.


We diagnose floaters and flashing lights by listening to your description of the symptoms and by examining your eye.


The inner part of the eye is made up of a clear, jelly-like fluid known as the vitreous. The vitreous helps maintain the shape of the eye and allows light to pass through the retina. Floaters are small clumps of gel that form in the vitreous. As we grow older, the vitreous shrinks and becomes more liquid. As it shrinks it tugs on the retina. This creates a sensation of flashing lights. Floaters and flashes are a normal part of the aging process and are not usually cause for alarm.

Causes of Floaters

In most cases, floaters are part of the natural aging process. They can be distracting at first, but eventually tend to settle at the bottom of the eye, below the line of sight but do not go away completely.

Floaters may be associated with:

  • Small flecks of protein or other matter trapped when the eye was formed before birth.
  • Natural deterioration of the vitreous fluid with aging, called a posterior vitreous detachment. This can also occur after laser treatments or surgery for cataracts or diabetic retinopathy. 
  • Nearsightedness.
  • Certain eye diseases or injuries such as diabetic retinopathy, retinal tears, retinal detachment, infection, inflammation (uveitis), and hemorrhaging.

Causes of Flashes

Flashes are associated with the same things that cause floaters. They can also be associated with migraine headaches. Flashes of light associated with migraines appear as jagged lines or heat waves in both eyes and can last for 10 to 20 minutes. If a headache follows the flashes, it is called a migraine headache. However, if there is no subsequent headache, the flashes of light are known as ocular migraines. If you think you are experiencing migraine headaches, contact us.

Lifestyle Management

Normally there is no need to treat floaters or flashes unless they are associated with a retinal tear or detachment. Flashing lights from a vitreous detachment will usually diminish over a period of several weeks or more. Flashing lights from an ocular migraine may recur with another migraine episode.

You may find that floaters initially interfere with your vision. New floaters are like new water spots on a window.  Initially, the spots can be very noticeable; but, over time, your eyes learn to look through them and you do not notice them in the window anymore. In the same way, the floaters will become less noticeable as your brain learns to see through them over a period of several weeks to several months.

If a floater appears directly in your line of sight, moving your eyes will cause the vitreous to swirl around and move the floater out of the way. Looking up and down rather than back and forth will cause different currents inside the eye and may be more effective in getting the floater out of the way.

Please contact us to make an appointment if you:

  • Suddenly develop floaters
  • Notice a change in the quantity or size of existing floaters in your eye
  • Have a family history of eye problems or retinal detachment
  • Have had an eye injury or previous retinal detachment

Your Care with Me

If you are having symptoms that concern you, please call our Appointment and Advice line, which is available 24 hours a day, 7 days a week.

We urge you to call under these special circumstances:
  • If you notice a sudden increase in flashes or in the number of floaters in the eye.
  • An area in your field of vision seems to be blocked or blacked out.

Our advice nurses can give you immediate advice, and our telephone staff can send me a message or book an appointment with your personal physician.

During your office visit, we will discuss your medical and family history and I will perform a physical exam. I will explain the findings of your exam and answer any questions or concerns you may have. We will discuss treatment options, and together well will create a treatment plan that is right for you.

If you need to talk with me after your visit or procedure, please call my office. You can also e-mail me with nonurgent issues from this website whenever it is convenient for you.

If you have urgent concerns or issues while my office is closed, or need general medical advice, you can call the Appointment and Advice line, available 24 hours a day, 7 days a week. You will be connected with a nurse who can give you immediate advice.

If you are experiencing an emergency, call 911 or go to the nearest Emergency Room.

Coordinating Your Care

Having all of our Kaiser Permanente departments located together or nearby, including pharmacy, laboratory, radiology, and health education, makes getting your care easier for you.

Another major benefit is our comprehensive electronic medical record system, which allows all of the doctors and clinicians involved in your care to stay connected on your health status and collaborate with each other as appropriate.

When every member of the health care team is aware of all aspects of your condition, care is safer and more effective.

If you come to an office visit
  • At the beginning of your visit, you will receive information about when you are due for your next test, screening, or immunization. We can discuss and schedule any preventive tests that you need. 
  • At the end of your visit, you may receive a document called the "After Visit Summary" that will summarize the issues we discussed during your visit. You can refer to it if you forget what we discussed. You can also view it online under Past Visits.
  • To help you prepare for your visit, please see additional details under Office Visit. 
If I prescribe medications

We will work together to monitor and assess how your medications are working and make adjustments over time. Prescriptions can be filled at any Kaiser Permanente pharmacy. Just let me know which pharmacy works best for you, and I will send the prescription electronically in advance of your arrival at the pharmacy.

If refills are needed in the future, you can:
  • Order them online or by phone. Order future refills from my home page or by phone using the pharmacy refill number on your prescription label.
  • Have them delivered to you by mail at no extra cost. Or you can pick up your medications at the pharmacy. If no refills remain when you place your order, the pharmacy will contact me regarding your prescription.
If lab testing or imaging is needed

For lab tests, I will use our electronic medical record system to send the requisition to the Kaiser Permanente laboratory of your choice. For imaging procedures, we will schedule an appointment with the Radiology department. When the results are ready, I will contact you with your results by letter, secure e-mail message, or phone. In addition, you can view most of your laboratory results online, along with any comments that I have attached to explain them.

If I refer you to another specialty colleague

If we decide together that your condition would also benefit from the care of other types of specialists, our staff will help arrange the appointment(s) with one or more of my specialty colleagues.

If surgery or a procedure is a treatment option

I will recommend you review educational information and tools to help you prepare for your procedure or surgery. The information will often help you decide whether surgery is right for you. If you decide to have a surgery or procedure, the information will provide details about how to prepare and what to expect.

If we proceed with surgery, I will have my Surgery Scheduler contact you to determine a surgery date and provide you with additional instructions regarding your procedure. Once your surgery is scheduled, a medical colleague of mine will contact you to conduct a preoperative medical evaluation that will assure that you are properly prepared for your surgery.

Convenient Resources for You

As your specialist, I have a goal to provide high-quality care and to offer you choices that make your health care convenient. I recommend that you become familiar with the many resources we offer so that you can choose the services that work best for you.

My Doctor Online is available at any time that is most convenient for you. From my home page you can:

Manage your care securely
  • View and compose secure e-mail messages.
  • Manage your prescriptions.
  • View your past visits and test results.
  • View your preventive services to see whether you are due for a routine screening or updated immunization.
Learn more about your condition
  • Read about causes, symptoms, treatments and procedures.
  • Find interactive health tools, videos, and podcasts to help you manage your condition.
  • View programs to help you decide on or prepare for a surgery or procedure.
Stay healthy
  • Locate health education classes and support groups offered at every medical center.
  • Explore interactive programs, videos, and podcasts that focus on helping you stay healthy.
  • View your Preventive Services to see whether you are due for a routine screening or updated immunization.

Related Health Tools:


See more Health Tools »

If you have an emergency medical condition, call 911 or go to the nearest hospital. An emergency medical condition is any of the following: (1) a medical condition that manifests itself by acute symptoms of sufficient severity (including severe pain) such that you could reasonably expect the absence of immediate medical attention to result in serious jeopardy to your health or body functions or organs; (2) active labor when there isn't enough time for safe transfer to a Plan hospital (or designated hospital) before delivery, or if transfer poses a threat to your (or your unborn child's) health and safety, or (3) a mental disorder that manifests itself by acute symptoms of sufficient severity such that either you are an immediate danger to yourself or others, or you are not immediately able to provide for, or use, food, shelter, or clothing, due to the mental disorder.

This information is not intended to diagnose health problems or to take the place of specific medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. If you have questions or need more information about your medication, please speak to your pharmacist. Kaiser Permanente does not endorse the medications or products mentioned. Any trade names listed are for easy identification only.

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