central serous chorioretinopathy

What is central serous chorioretinopathy?
Central serous chorioretinopathy (CSCR), sometimes called central serous retinopathy or choroidopathy, is a condition in which fluid builds up under the retina, almost like a blister.  This causes a serous detachment of the neurosensory retina, which results in sudden blur and distortion of central vision, usually in one eye only.

Retinal photo of a patient with CSCR (see the bubble in the center?)

Who gets CSCR?
CSCR is more common in males, usually between the ages of 20 and 50.  The exact cause is unknown, but stress and steroid use are risk factors (1).  

How is it diagnosed?
The patient's symptoms and the clinical appearance on dilated examination is usually sufficient to make a diagnosis of CSCR.  A couple of additional tests may be used to confirm the diagnosis and monitor resolution:

• Optical Coherence Tomography (OCT)- A scanning laser creates a cross-sectional image of the layers of the retina and allows eye doctors to measure the thickness of the retina.  Below is the macula OCT of the same patient whose retina is in the photo above.

Macula OCT of the same CSCR patient

• Fluorescein angiography (FA)- Fluorescein dye is injected into a vein in the arm, and photos of the retina are taken as the dye travels through to the vessels of the retina, highlighting areas of leakage.

What is the treatment?

Most cases of CSCR resolve on their own within 3 or 4 months, so observation is most appropriate. In cases where visual recovery is urgent, or the CSCR does not resolve on its own after a few months (which can be up to 20% of cases 2), intervention may be indicated. These cases may be treated with laser, though the end result with and without treatment has been found to be similar. There are many investigational treatments involving the use of oral medications (most recently, eplerenone) or anti-VEGF injections, but nothing definitive has been concluded based on the studies.  In up to half of CSCR cases, the condition recurs (3).   

CliffsNotes: Central serous chorioretinopathy is a blister-like fluid accumulation under the retina. It blurs and distorts central vision, but usually resolves on its own in a few months.

Glaucoma Awareness Month

January is Glaucoma Awareness Month, so I think we all know what this month's post is about. According to the World Health Organization (WHO), glaucoma is the second leading cause of blindness world-wide (1), and Open Angle Glaucoma affects more than 2 million people in the US alone (2).

A cupcake rendition of the optic nerve

What is glaucoma?
Glaucoma is a group of diseases that damage the optic nerve. The optic nerve is like a cable, made of about 1 million nerve fibers, that sends signals from the retina (the tissue that lines the back of the eye) to the brain. When the optic nerve is damaged, permanent vision loss results.

There are many types of glaucoma, the most common of which is Primary Open Angle Glaucoma (POAG). In most cases of glaucoma (but not all!), the pressure within the eye is higher than normal. The eye has a clear fluid, called aqueous humor, that circulates in the front part of the eye and flows out through a structure called the angle (here is a good visual). Through various mechanisms, this fluid may not flow out of the front of the eye properly, leading to elevated eye pressure, or intraocular pressure (IOP). High IOP can slowly damage the optic nerve over time.


How do I know if I have glaucoma?
Most cases of glaucoma do not have symptoms early on. Peripheral vision loss occurs, but by the time you notice this, the disease is substantially progressed and significant, permanent vision loss has occurred. Since there really aren't symptoms to watch out for, early detection during yearly eye exams is key.

There are some factors that increase risk for glaucoma:

• a family history of glaucoma
• being of African-American or Hispanic descent
• older age 
• high eye pressure
• thin corneas

*Note: People of any age, race, or eye pressure level can have glaucoma.

Glaucoma can also result from another disease or condition, like eye trauma or inflammation. Additionally, some studies have shown a relationship between glaucoma and conditions of altered blood flow (ie: sleep apnea, diabetes, migraines, high or low blood pressure).

How is glaucoma diagnosed?
Glaucoma is a complex disease, so many areas need to be looked at to obtain an appropriate diagnosis and management plan. Some procedures that may be involved in the diagnostic/management process:

• Tonometry: A tonometer probe is used to gently measure intraocular pressure (IOP) in millimeters of mercury. "Normal" IOP is typically under 21mmHg, though you can have glaucoma with normal IOPs. You can also have higher than normal IOPs without having damage to the optic nerve.
• Perimetry/Visual Field Testing: A visual field test assesses the function of the optic nerve. When enough nerve fibers are damaged, you develop missing spots in your field of vision. The visual field test picks up these missing spots early on (far, far sooner than you would pick them up on your own). 
• Pachymetry: This test measures the thickness of the central part of your cornea. Thinner corneas not only underestimate eye pressure, but they have also been shown to be a risk factor for glaucoma progression (3,4).
• Gonioscopy: A lens with mirrors is placed on the eye, allowing your eye doctor to get a closer look at the drainage angle of the eye. 
• Dilated fundus exam: Your eye doctor uses a high-powered lens and a slit lamp to evaluate the health of the optic nerve, best viewed through a dilated pupil. Your eye doctor may choose to take photos as well, similar to the one seen below.
• GDx, HRT, OCT: In addition to directly evaluating the optic nerve, there are scans that can be used to image the optic nerve and further assess its structure. These scans give information on the amount of optic nerve tissue loss and the rate of nerve fiber thinning. The structural defects on the optic nerve should correlate with the functional defects in the visual field.

End-stage glaucoma

How is glaucoma treated and managed?
There is no cure for glaucoma, but the damage it causes can be slowed by the use of medications and/or surgery. Of the risk factors mentioned, the only one we can control is eye pressure, so that is the focus of treatment. The goal is to increase outflow of the fluid in the eye, or decrease production of that fluid, or both. This can be achieved using medications (typically eye drops), laser procedures, or glaucoma surgery. The course of treatment depends on both the type and severity of glaucoma.

What about marijuana?  I've been asked this question more than once. Marijuana is not a legitimate form of glaucoma therapy. Yes, a study from 1971 showed that smoking marijuana reduces eye pressure, but only for about 3-4 hours after smoking (5). Glaucoma management requires around-the-clock IOP control. Drops and/or surgery are much more effective at lowering IOP over the long-run and are less detrimental to your health, so I do not consider marijuana an appropriate glaucoma treatment.


What is the prognosis?
Left untreated or uncontrolled, glaucoma can lead to blindness. But the good news is it can be diagnosed on routine eye exams, and it is treatable. See your optometrist at least every 1-2 years, or more frequently if warranted. This is especially important for those with several risk factors. If you are diagnosed with glaucoma, it is important that you are compliant with the treatment and follow-up regimens outlined by your eye doctor. Effective management requires a team effort between you and your eye doctor.


CliffsNotes: Glaucoma is a leading cause of blindness. Know the risk factors and see your eye doctor regularly!

Additional Recommended Resources:

• Glaucoma Research Foundation
• AOA: Glaucoma
• NEI: Glaucoma
• All About Vision: Glaucoma

diabetes and the eye

Today is World Diabetes Day, and this month is American Diabetes Month, so it seems like a great time to talk about diabetes!  I would venture to guess that almost everyone reading this post either knows a person with diabetes or has diabetes themselves.  According to the 2014 Center for Disease Control (CDC) National Diabetes Statistics Report,  9.3% of the US population has diabetes, and 27.8% of those with diabetes are undiagnosed.  That means nearly 1 in 10 Americans have diabetes, and more than 1/4th of those with it don't know it.  The increasing prevalence of diabetes has been referred to by many as a global epidemic.  In this post, we'll briefly go over what diabetes is, and then we'll go into detail about how diabetes affects the eye.

What is diabetes?  Diabetes is a group of diseases characterized by high blood glucose levels as a result of either a problem with how insulin is produced or how insulin works, or a combination of both.  Glucose is the body's main source of energy, derived from the food we eat.  Insulin is a hormone that allows glucose to be absorbed from the blood and converted to energy.    

• In Type 1 diabetes, the body attacks the beta cells of the pancreas, which are responsible for producing insulin.  As a result, the pancreas produces too little or no insulin.  So a person with Type 1 diabetes depends on outside sources of insulin, such as insulin injections, insulin pumps, or even inhaled insulin, to be able to metabolize glucose.  This type of diabetes is typically diagnosed early in life, and it accounts for about 5% (CDC) of diabetes cases.  
• In Type 2 diabetes, the body either doesn't produce enough insulin or the cells of the body don't use the insulin produced properly.  Most people with this type of diabetes are able to achieve blood glucose control with diet, physical activity, blood glucose monitoring, and oral medication as needed, although some require insulin therapy.  Type 2 diabetes is usually diagnosed in adulthood, and accounts for 90-95% of all cases.  Risk factors for Type 2 diabetes include a positive family history of the disease, being overweight, physical inactivity, age, ethnicity (African Americans, Hispanics/Latinos, Native Americans, Asian Americans and Pacific Islanders are at particularly high risk), a history of gestational diabetes, pre-diabetes, high blood pressure, and high cholesterol (AOA).
• Gestational diabetes is glucose intolerance experienced during pregnancy.  It is typically diagnosed during the 2nd or 3rd trimester.
• Pre-diabetes is a term used to refer to above-normal blood glucose levels that are below the threshold for diagnosing diabetes.  Intervention (ie: healthy diet, physical activity, weight loss) can reduce the rate of conversion from pre-diabetes to diabetes.  In 2012, the CDC found that 37% of Americans 20 years of age and older fell into the pre-diabetes category in 2009-2012 (CDC).

How does diabetes affect the eye?   

• The most common eye disorder associated with diabetes is diabetic retinopathy.  Diabetic retinopathy is progressive damage to the small blood vessels that supply the tissue lining the inner surface of the eye (the retina).  The AOA has some great videos to help illustrate the disease here.  Diabetic retinopathy is the leading cause of new cases of blindness and low vision in Americans age 20 to 74 (AOA).   In 2005–2008, of adults diabetics 40 years of age or older in the US, 28.5% had diabetic retinopathy, and 4.4% had advanced diabetic retinopathy—with conditions such as clinically significant macular edema and proliferative diabetic retinopathy—that could lead to severe vision loss (CDC).  

Proliferative diabetic retinopathy

• Non-proliferative diabetic retinopathy (NPDR) occurs when the capillaries of the retina balloon (microaneurysms) due to weakening of the vessel walls.  They may leak blood (hemorrhages) and/or fat deposits (exudates) into the retina.  NPDR is classified in 3 stages- mild, moderate or severe.  No treatment is typically indicated for milder cases, unless there is clinically significant macular edema present.  Frequent monitoring is imperative, as more severe cases may warrant treatment. 
• Proliferative diabetic retinopathy (PDR) occurs when blood vessels that nourish the retina become blocked, shutting down the blood supply to parts of the retina.  The retina then sends out signals to grow new blood vessels (neovascularization).  These new vessels grow on the surface of the retina and/or into the gel-like substance that fills the back of the eye (the vitreous).  These new vessels are bad news because they have weak, thin walls that can leak blood or cause scar tissue to grow.  PDR has a high risk of vision loss if it is left untreated. Typical treatments may include scatter laser therapy (PRP), injecting medications into the eye (intravitreal injections), and/or removing and replacing the vitreous (vitrectomy).   
• Macular edema results when the capillary walls weaken and allow fluid to leak into the area of the retina that is responsible for your central, sharpest vision (the macula).  Macular edema can occur at any stage of diabetic retinopathy, and can even be present with 20/20 vision.  Like PDR, macular edema has a high risk of vision loss if it is left untreated.  Treatment for macular edema is typically intravitreal injections, and/or focal laser therapy if needed.  

              Some tools your eye doctor may use to diagnose and evaluate diabetic retinopathy: 

• Retinal cameras are used to take photographs of the retina (like the one seen above) in order to monitor retinopathy.
• Optical coherence tomography (OCT) can be used to evaluate how much swelling or edema is present.  An OCT is a scanning laser that can assess the thickness of the retina. 
• Fluorescein angiography (FA) may be ordered to evaluate leakage and guide treatment.  A dye is injected into a vein in the arm and photos of the retina are taken as the dye reaches the retinal vessels.

• Other eye disorders associated with diabetes: 

• A cataract is a clouding of the lens of the eye.  It often develops earlier and progresses more rapidly in diabetics compared to non-diabetics (AOA).  
• Eye movement disorders can occur secondary to diabetic neuropathy, resulting in double vision.  
• The optic nerve can also be affected.  There may be swelling (diabetic papillopathy) or damage due to insufficient blood supply (anterior ischemic optic neuropathy) (ADA).
• Diabetes can also cause blurred vision in the absence of all of the above.  It is believed that high blood glucose levels cause increased fluid absorption in the lens of the eye, thus changing its shape and causing fluctuations in vision.  

How often should a diabetic see their optometrist?  Type 1 diabetics should have a dilated eye exam within 5 years of diagnosis, and at least yearly thereafter.  Type 2 diabetics should have a dilated eye exam upon diagnosis, and at least yearly thereafter.  Your optometrist may suggest more frequent examinations based on the presence and severity of diabetic eye disease, or they may refer you to a retinal specialist for treatment if indicated.  The strongest predictor of diabetic retinopathy is the duration of diabetes, so it becomes increasingly important for diabetics to have regular eye exams.  Do not wait for symptoms to see your eye doctor!  Early intervention is key.

CliffsNotes: Diabetes is a multi-organ disease, and avoiding its complications takes a life-long commitment.  Yearly dilated eye exams are an important part of that commitment.  

Additional recommended resources:

• NEI: Diabetic Eye Disease
• AOA: Diabetic Retinopathy
• American Diabetes Association (ADA) 
• dLife
• World Diabetes Day

healthy vision month

May is Healthy Vision Month (nei.nih.gov/hvm)!  Yes, I realize May is almost over.  In my defense, I wrote most of this article a couple of weeks ago.  It just took so long to post because I couldn't decide on fonts for the blog...

Even though I was visiting the eye doctor fairly regularly as a child and a teenager, I didn't really have a clue what was being done during the exam or why it was being done until I began looking into optometry as a career.  I think it's important to know at least a little about what your eyes do, how they work, and why it's important to get them checked regularly.  I will try not to bore you too much and just hit the high points!

• On the most obvious level, your eyes allow you to see the world around you.  The goal is to have clear, comfortable, and single vision.  Eye doctors have multiple tools they can utilize to achieve this goal, such as glasses, contact lenses, vision therapy, and surgery.  But "seeing well" is only a piece of the puzzle and is not an indication of your eye health.

• Aside from revealing signs of eye infections, glaucoma, cataracts, and macular degeneration, your eye exam can also reveal general health problems.  Your eyes are connected to the rest of your body, so conditions that affect your body can manifest in the eyes.  The eyes are the only place in the body where your blood vessels can be viewed directly and non-invasively.  Through a dilated eye exam, your eye doctor can examine the blood vessels and tissue of the back of the eye (the retina), which can reveal signs of systemic conditions such as diabetes, hypertension, anemia, cardiovascular disease, and more.  Some of these conditions can present with no symptoms early on, so it is important to see your eye doctor regularly.

photo of the back of the eye

• Your eyes are an extension of your brain.  Visual processing begins at the retina of the eye and ends at the visual cortex of the brain.  Many aspects of an eye exam evaluate the state of the visual pathway, including pupil testing, visual fields, extra-ocular motility testing, and fundus examination.  These tests can uncover central nervous system issues such as multiple sclerosis, brain tumors, increased intracranial pressure, brain aneurysms and more.  

So now that we've covered why you need an eye exam, let's discuss how often you should have an eye exam.  

• ADULTS:  The American Optometric Association (AOA) recommends that asymptomatic/risk-free adults have an eye exam at least every 2 years until age 60, and every year thereafter.  Adults “at risk” are recommended to have eye exams every 1-2 years, or as deemed appropriate by their eye care professional.  Many of us fit into the “at risk” category, as that includes people who wear contact lenses, people with a family history of eye diseases like glaucoma or macular degeneration, people working in occupations with high visual demands or eye hazards, and people with diabetes, high blood pressure, or other vascular abnormalities.  I personally recommend a comprehensive eye exam at least every year for most patients, but it's particularly advised if you fall into this group.  
• CHILDREN:  The AOA recommends an eye exam at 6 months old, 3 years old, before first grade, and every two years after that for asymptomatic/risk-free children.  As with adults, the recommended frequency of examination increases if the child is “at risk,” which can include those children born premature, those with developmental delays, those with eye turns, and those with a high prescription in one or both eyes.  While vision screenings at school and at the pediatrician's office are incredibly valuable tools, they do not replace comprehensive eye exams.  I cannot stress enough the importance of getting children to the eye doctor early.  The sooner things like eye turns and high prescriptions can be detected, the better the visual prognosis for the child.  I will dedicate a separate post to children's eye health in the future.

I hope this post gave you some insight into eye examinations and why they are an important part of your health care.  As always, feel free to email me with any questions, comments, or concerns.  Thanks for visiting, and I hope you continue to follow the blog!