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

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The small veins that carry blood away from the retina can become blocked, particularly in elderly people. When this happens, the condition is called retinal vein occlusion (RVO). It is sometimes described as an “eye stroke” because the underlying process and symptoms closely resemble those of a stroke.

One major artery carries blood to the retina, and one major vein – the central retinal vein – drains blood back to the heart, assisted by a network of smaller branch retinal veins. When a retinal vein becomes blocked, blood can no longer flow easily. This causes blood to back up, increasing pressure in the vein. This pressure can damage vessel walls and also prevent blood from flowing into the retina. Blood and fluid may leak out, causing swelling in the surrounding retinal cells. Depending on the location and severity of the RVO, you may experience mild or severe vision loss.

Similar to stroke, evaluating RVO focuses on finding the cause of the blood flow interruption and taking steps to reduce the risk of another RVO. We may recommend treatment to reduce swelling and promote circulation.


Retinal vein occlusions are classified into different types depending on location of the occlusion. The extent of your symptoms will depend on which type of RVO you have and the severity of its presentation. Two of the most common types include:

Branch retinal vein occlusion (BRVO) develops when a branch retinal vein is affected by a blockage or other event that impairs blood flow. Retinal hemorrhages and swelling are localized only to the area of the blood vessel involved.

Central retinal vein occlusion (CRVO) is a blockage in the central retinal vein resulting in widespread hemorrhages and swelling.


There are a number of risk factors that can increase your chances of developing a blockage that can lead to a retinal vein occlusion. These factors include the following:

  • Atherosclerosis. Atherosclerosis is caused by cholesterol plaques that develop within the arteries. Left untreated, the condition can eventually block an artery and/or cause blood clots.
  • High cholesterol. If your overall cholesterol is high, this puts you at risk for developing cholesterol plaques that cause hardening of the arteries.
  • High blood pressure. Increased pressure places extra force on the blood vessels in your eye. Eventually, this can lead to damage to the blood vessel walls. 
  • Diabetes. If you have diabetes, particularly if your blood sugar levels are not well controlled, you are at higher risk of developing severe symptoms from an RVO. The blood vessels in your retina may have already been weakened by high blood sugar, making it easier for them to rupture if a vein blockage occurs. 
  • Uncontrolled glaucoma. High pressure inside your eye from glaucoma or other causes also increases the risk of RVO.
Additional References:


If you have an RVO you may, or may not, have any symptoms. The proximity of the RVO to the center of the retina affects whether central vision decreases. If the RVO is very close to the center, vision loss may be sudden and extensive. This is more often the case with CRVO.   


We can schedule a general eye exam for you in either our Optometry or Ophthalmology departments. However, if you have sudden vision changes, contact us to schedule an urgent appointment in Ophthalmology.

We will ask you about your symptoms and examine your eyes. If we suspect an RVO, the examination will include the following tests:

  • Ophthalmoscopy. We use a strong light and magnifying lens to examine your retina and macula. We usually administer eyedrops first to dilate your pupils so that we can see the structures at the back of your eye clearly.
  • Visual acuity test. This tests the strength of your central vision by requiring you to read letters on a wall chart some distance away.
  • Tonometry. This is a standard measurement of intraocular pressure (IOP).
  • Fluorescein angiogram/optical coherence tomography (OCT). A fluorescein angiogram allows us to look closely at the blood flow in the vessels in your eyes. We inject a vegetable dye into a vein in your arm. As the dye travels through the blood vessels in your retina, photos are taken of your eye. We may also perform an optical coherence tomography (OCT) test to measure the thickness of your retina and look for edema. OCT is a type of scanner that uses light waves to map the retina. This test is noninvasive and painless and often takes less than 10 minutes.

Other Tests

If you have an RVO, it increases your risk of developing other vascular conditions, such as a stroke or heart disease. If we suspect you are at risk of developing any of these conditions, we may recommend that you discuss further testing and lifestyle management strategies with your primary physician.


If you have a BRVO, you may not need any treatment. We may check your eye regularly and allow it to resolve on its own. If the BRVO does not get better, or if you have a CRVO, there are a number of treatment options that we will discuss with you.

Laser Treatment

During laser photocoagulation we use a laser to create tiny burns that seal off the blood vessels that are leaking blood and fluid into your eye. These treatments usually take about 10 to 20 minutes and may cause slight discomfort.

  • Anti-VEGF medicines. We may recommend injecting anti-vascular endothelial growth factor (VEGF) medicines directly into your eye. VEGF is a protein that supports the growth of abnormal blood vessels in the eye. By interrupting the effects of VEGF, anti-VEGF drugs can stop the growth of new abnormal blood vessels, reduce fluid leakage, and slow further vision loss.
  • Anti-inflammatory corticosteroids. We may recommend injecting a corticosteroid into your eye (intravitreal injection) to reduce macular edema. There are risks involved, and we will discuss these with you as well as the benefits of this treatment approach.

Lifestyle Changes and Management

Developing an RVO means that you are also at risk for developing other vascular problems including stroke and heart disease. There are a number of things you can do to reduce your risk of having another RVO or developing other conditions related to your vascular system. We recommend that you discuss these steps with your personal physician:

Know your blood pressure

If your blood pressure is high (more than 140 systolically and more than 90 diastolically), talk to your personal physician about ways to reduce it. We have a range of resources to help you eat better and maintain a healthy weight, take medication, stop smoking, and get more exercise. 

Control your cholesterol

Your personal physician can discuss your cholesterol levels with you and recommend treating elevated cholesterol, especially elevated LDL (known as bad cholesterol) with statin-type drugs that have been shown to reduce the risk of subsequent stroke. The target LDL cholesterol for people who have had a vascular event is less than 100. If you have diabetes and have had an RVO or ischemic stroke, then your LDL should be less than 70.

Quit smoking

Quitting smoking, if you smoke, is one of the best things you can do for your health. Stopping smoking significantly reduces your risk of having a vascular event. 

Anticlotting agents

Your personal physician may recommend a medication to reduce the chance of future blood clots forming. These include:

  • Aspirin. Patients at high risk of ischemic stroke taking aspirin have a 20 to 30 percent lower risk of ischemic stroke compared to those not taking aspirin.
  • Aspirin-Persantine combination treatment. These medications, taken in combination, can be effective in reducing your risk for ischemic strokes and may be prescribed for some people instead of aspirin.
  • Clopidogrel. This medication, classified as an anti-platelet agent, is a good alternative for patients who cannot tolerate aspirin products.
Additional References:

Your Care with Me

If your optometrist identifies a problem with your retina during your regular eye exam, he or she will make an appointment for you to see me, or one of my colleagues, in the Ophthalmology department. If you are not scheduled for a regular eye exam, and you notice symptoms such as vision loss, particularly in your central vision,  please call our Appointment and Advice line, which is available 24 hours a day, 7 days a week.  Our advice nurses can give you immediate advice, and our telephone staff can send me a message or book an appointment for you.

Your first appointment is likely to take at least 1 hour and possibly longer. During your office visit, we will discuss your medical and family history and I will perform a comprehensive eye exam and some diagnostic tests.

I may administer eyedrops to dilate your pupils so that I can clearly see the structures of your eyes. Your pupils will remain dilated for several hours, so you may wish to bring someone who can drive you home after your exam.

I will explain the findings of your exam and answer any questions or concerns you may have. If you notice any new changes, please let me know.

If we decide that you need further evaluation, or further treatment or surgery, I will discuss the treatment options that are available, and together we 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:


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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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