“Other” Eye Conditions Eye News Testing

Coronavirus | 2019-nCoV & Eye Disease

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The new coronavirus recently discovered may cause eye symptoms in infected individuals.  This article is meant to highlight the information made available to the public as health agencies such as AAO (The American Academy of OphthalmologyAOA (American Optometric Association), WHO (World Health Organization), and the CDC (Centers for Disease Control) who are collecting and dispersing information as we learn more about this global outbreak.

Coronaviruses are not new.  While several variants cause mild infections, they are also responsible for the SARS, MERS and the present novel coronavirus outbreaks where infections can be deadly.  The novel Coronavirus (dubbed 2019-nCoV) has not been identified previous to December 2019 where it initially was reported to have infected six patients in Wuhan City, Hubei Province, China.

There are 7 known coronaviruses.  This family of viruses are zoonotic, that is, they are capable of infecting both animals and humans.  The SARS coronavirus was found to be transmitted from civet cats to humans. The MERS coronavirus can be transmitted between dromedary camels and humans. 

Based on genomic sequencing for the virus, the origin of 2019-nCoV is suspected to be batsAnother technical name for the novel coronavirus is SARS-CoV-2 and is closely related to SARS-CoV-1, the virus responsible for SARS.  SARS-CoV-1 also finds its origins in bats.  

The coronavirus is known to be at least as infectious as the influenza virus.  It is believed to be transmitted principally by aerosolized germs and/or direct contact.  

The disease causes respiratory symptoms:  cough, shortness of breath and pneumonia 

2019-nCoV (Coronavirus)

2019-nCoV is the name of the novel coronavirus.

There are seven known coronaviruses that infect humans.  Coronaviruses were first described in the 1960s.

Four viruses cause mild disease: HKU1, NL63, OC43 and 229E.

Three can cause deadly disease: SARS CoV-1, MERS, and SARS-CoV-2.

Coronaviruses cause similar symptoms to a cold are flu and are largely believed to spread from person to person via aerosolized respiratory droplets released when a person coughs or sneezes.  

Symptoms of COVID-19

The official name of the disease caused by coronavirus 2019-nCoV is called COVID-19.  COVID-19 stands for COronaVIrus Disease 2019.  

2019-nCoV causes COVID-19. 

Symptoms of coronavirus are similar to the flu:

  • Runny nose
  • Sore throat
  • Headache
  • Fever
  • Cough
  • Malaise
  • Shortness of breath

Coronaviruses can also cause pneumonia and bronchitis, but occurs more often in people with cardiopulmonary disease, compromised immune systems, infants and the elderly. 


The viral infection may cause conjunctivitis.  Symptoms include redness, discharge, photophobia and irritation.  Patients who have symptoms of conjunctivitis and respiratory symptoms (cough, shortness of breath, others?) and who have travelled recently to China (or who have been exposed to  may be carriers. 

Conjunctivitis caused by the virus is thought to be self-limited and not known to cause any damage to the eye. 


This recently identified coronavirus is similar to the SARS (Severe Acute Respiratory Syndrome) coronavirus and the MERS (Middle East Respiratory Syndrome) coronavirus.  As of this writing, it may be more contagious and has already caused more fatalities than the SARS outbreak. Starting in 2002, 8098 cases of SARS were reported including 774 deaths.  

The exact mechanism of transmission is not known, but person-to-person contact seems to be the predominant way the virus is spread.  Because some patients have conjunctivitis, health officials recommend protecting the eyes as a precaution to prevent spread, that is, it may be possible to contract the disease by getting droplets splashed or rubbed into the eyes.

Current recommendations also include thorough handwashing, covering your mouth and nose when sneezing (actually sneezing into your arm/elbow and not your hands is recommended) and avoid close contact with someone who may be ill.  Close contact is defined as being within 6 feet of an individual.

The virus seems to be very contagious.  The virus may have an incubation time of at least 14 days, perhaps longer.  Incubation time is defined as the time between contracting the virus and showing the first symptoms of disease.  It is likely that patients can be “carriers” (spreading the disease) during the incubation period.  

Healthcare Providers – PUI

The following resource from the CDC explains best practices for evaluating and reporting persons under investigation (PUI)

Healthcare providers are requested to take a detailed travelled history when contacting patients with fever and signs of lower respiratory illness (cough, shortness of breath).  Those patients seen with symptoms of conjunctivitis should also be evaluated for fever and respiratory illness. 

Travel history is conducted to identify patients with a travel to mainland China, especially Hubei Province, China OR who have had close contact with a confirmed 2019 nCoV patient within the past 14 days of onset of symptoms should be further evaluated.

Healthcare providers are urged to contact state and local health agencies. 


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Retina Testing

Fluorescein Angiography

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There are several diagnostic tests used by a retina specialist which provide us with unique information about the health of the retina.  A fluorescein angiogram has long been the gold standard of the retina specialist to study;

  1. Patients with diabetic retinopathy
  2. Macular degeneration
  3. Abnormal swelling of the retina
  4. Retinal Vascular Occlusions

The study principally allows the retina specialist to study abnormalities in blood supply and blood flow of the retina.

The Fluorescein Angiogram

To perform the test, a small amount of fluorescein dye is usually injected into an arm vein.  The same vein used when drawing blood, located in the antecubital fossa of your forearm, is usually sufficient.

The dye then travels to the retina in 12-20 seconds.  A series of photographs are now taken as the dye circulates through the retina.

Thanks to digital photography, the results are reviewed instantaneously by your retina specialist.  Before digital photography, camera film needed to be processed before the results could be reviewed adding hours or days to the process.

Reactions to Fluorescein

As with any compound, certain patients can have a reaction to fluorescein.  Symptoms can range to itching, hives, nausea/vomiting or worse, severe anaphylaxis.

Death from anaphylaxis due to fluorescein is very unlikely and estimated to be about 1 chance in 220,000.

Fluorescein angiography is performed in the presence of a medical doctor.

Because fluorescein is unique to ophthalmology and is a plant based vegetable dye, there is no chemical similarity to the contrast dyes used in radiologic xrays and MRIs.

Results of the Fluorescein Angiogram

This test is very helpful in confirming the diagnosis of many disease or elucidating the cause of subtle changes in vision.

In cases of macular degeneration, an “FA” can:

  1. Confirm the diagnosis of ARMD
  2. Determine any evidence of the wet form of macular degeneration
  3. Provide evidence of progressive changes (when compared to previous studies)

In cases of diabetic retinopathy, a fluorescein angiography can be useful for:

  1. Demonstrating otherwise undetectable evidence of early disease
  2. Provide proof of macular edema, a common complication of diabetic retinopathy
  3. Demonstrate evidence of neovascularization of the retina, a potentially blinding complication

Overall, the fluorescein angiogram is regarded as a very safe and effective diagnostic tool for the retina specialist.  Other diagnostic testing for retinal diseases includes the OCT, or optical coherence tomography.


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Testing Treatments

What is OCT? | Optical Coherence Tomography

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OCT stands for optical coherence tomography and is an important diagnostic tool used by most eye doctors, but is exceptionally useful to the retina specialist.

OCT can be used alone to study the retina or in conjunction with a variety of other testing modalities to include retinal digital photography and fluorescein angiography.   This non-invasive test may be used to help diagnose and treat glaucoma and retinal diseases although the testing procedure is not exactly the same.

The test provides information in “high-definition” due to its ability to examine and provide information down to the micrometer level.  Before OCT, this resolution of testing was not possible.

Optical coherence tomography may be performed on the retina and separately focused on the optic nerve (glaucoma).

This article focuses on OCT for retinal diseases and how it has become the mainstay of diagnostic testing which offers different information than a fluorescein angiogram.

What OCT

This is a painless non-invasive test using light waves to examine the different layers of the retina.  The surface topography can also be examined.

By the way, tomography allows us to examine a tissue in cross-section, whereas topography allows us to examine the surface of a tissue.

Results of an OCT are best if the pupils are dilated, but dilation is not necessary.

An OCT is obtained by placing resting your chin on the machine while keeping your eyes and head as still as possible.  Nothing will touch your eyes.

The scan will take several minutes while you look at a target keeping your eyes still.

When to Use OCT

OCT is very useful to the retina specialist to evaluate common retinal diseases such as:

  1. Macular holes
  2. Macular pucker
  3. Macular edema caused by various conditions such as retinal vascular occlusions (RVO)
  4. Macular degeneration (ARMD)
  5. Central serous retinopathy (CSR)
  6. Diabetic retinopathy
  7. Vitreomacular traction (VMT)

Optical coherence tomography is extremely useful in monitoring the effectiveness of a treatment and answers the question, is the patient getting better?

OCT has a few limitations.  The test is very difficult to perform in situations where light is blocked from entering the eye, such as:  dense cataracts or vitreous hemorrhage.

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“Other” Eye Conditions Testing

Retina Scan May Diagnose Alzheimer’s Disease

Retina Scan to Diagnose Alzheimer's DiseaseResearchers hope that a simple retina scan may prove to be a useful tool to diagnose Alzheimer’s disease (AD).  The scan, optical coherence tomography angiography (OCTA), is a non-invasive test which may also be used as a screening tool to identify patients at risk who are not yet showing symptoms of Alzheimer’s disease.

Atrophy or shrinking of the  hippocampus, a portion of the brain integral to memory, is often found in patients with early signs of AD.  

The retina scan is based upon the correlation between thinning of the retina and the shrinking portion of the brain.  Using a patient’s own red blood cells instead of an injected dye, the OCTA can measure minute changes in the thickness of the retina.

Symptoms of Alzheimer’s Disease

Alzheimer’s disease, also called senile dementia, primarily causes memory loss and confusion.   I should stress that there are many other diseases which share the symptoms listed below and proper diagnosis can only be made with a thorough medical exam.

Symptoms of AD include:

  • Memory loss, e.g. difficulty remembering events
  • Inability to concentrate, planning and problem solving are difficult
  • Difficulty completing routine tasks at home/work
  • Confusion with respect to location or passage of time
  • Getting lost – not understanding driving distances, misplacing items
  • Jumbled language and using words
  • Poor judgement and decision making

Diagnosis of Alzheimer’s Disease

There is no single test to diagnose Alzheimer’s disease.  The diagnosis is made only after a complete medical history, a thorough medical exam and ancillary testing.

Your doctor will use a multifaceted approach to make the diagnosis of AD and to insure that there are no other medical diseases which can mimic the symptoms of AD.

Additional testing may include:

  • Blood tests – while there is no diagnostic blood test for Alzheimer’s, but testing may rule out other diseases
  • Brain imaging may help support the diagnosis of AD and rule out other causes such as bleeding, tumors or stroke
  • Brain scans
    • MRI – magnetic resonance imaging
    • CT – computerized tomography
    • PET scan – positron emission tomography

Presently, the diagnosis of AD is not made easily.  The diagnosis requires individualized evaluation and use of expensive ancillary testing and scanning.

There is no screening test of those at risk for developing Alzheimer’s disease.  Identifying individuals at risk for developing the disease will allow early institution of treatment and future planning.  

The OCTA retina scan may indeed become an inexpensive, yet specific, method for screening and making the diagnosis of Alzheimer’s disease.

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