Why consider genetic testing?

Genetic testing is used to identify gene variants known to cause certain eye problems.  Testing may be helpful to confirm a diagnosis suspected on clinical findings.  Knowing the causative gene may also be helpful to better understand the inheritance pattern in order to inform other family members and to assist with family planning.  Finally, much research and progress have been made in the treatment of inherited eye disease. 

What tests are available?

There are a number of options when it comes to genetic testing.  In general, it is better to order specific test panels rather than testing all of the genes (whole-exome sequencing).  For example, there are tests geared to identify specific inherited retinal diseases (IRD) with a high degree of accuracy.

Who pays for genetic testing?

Insurance companies generally do not cover the cost of genetic testing.  The cost of testing is variable depending on the lab and the scope of the tests.  For example, Molecular Vision Lab charges $650 for a test panel of 1024 genes looking for inherited retinal disease. 

How can I get genetic testing?

If your ophthalmologist suspects an inherited retinal disease, he/she may order testing.  The type of test will depend on the diagnosis under consideration.  If you are a resident of the United States and have not had prior testing, you may be eligible for testing at no charge.  However, you may be asked to participate in a program in which you may be contacted by researchers.  Certainly, you may choose to keep your personal information private.  

Over time, I anticipate genetic testing will become more readily available and the cost will be covered by insurance.  The treatment and cure of some inherited retinal diseases is now a reality, and the future holds the promise of further progress with continued research. 

By Scott E. Pautler, MD

For a telemedicine consultation with Dr Pautler, please send email request to spautler@rvaf.com. We accept Medicare and most insurances in Florida. Please include contact information (including phone number) in the email. We are unable to provide consultation for those living outside the state of Florida with the exception of limited one-time consultations with residents of the following states: Alabama, Arkansas, Connecticut, Georgia, Minnesota, and Washington.

Copyright  © 2022 Designs Unlimited of Florida

What is oral fluorescein angiography?

Fluorescein angiography (FA) is a useful method of photographing the eye.  Although it is usually used to study the blood flow to the retina, it is also used to study the iris and other eye structures.  FA is usually performed by injecting fluorescein dye into a vein of the arm, after which special photographs are taken of the eye.  However, when a vein is not easily accessible, the dye may be administered by mouth in the form of a drink.  

When to consider oral fluorescein angiography?

Oral fluorescein angiography may be considered whenever access to a vein presents a challenge.  Sometimes, this situation is encountered with children or adults who are strongly averse to pain, as the dye injection may be uncomfortable.  In other cases, the veins are simply too small or are otherwise difficult to inject.  In these instances, oral fluorescein angiography may be considered as an alternative to intravenous FA.  

What is the disadvantage of oral fluorescein angiography?

The main disadvantage of oral FA is a potential decrease in the quality of the images of the retina.  However, there are several steps that may be taken to optimize the image quality.  Another disadvantage of oral FA is that the dye tastes bitter.  The may be overcome, in part, by mixing the fluorescein dye with apple juice or with water sweetened by sugar or a non-nutritive sweetener.    

How is the procedure performed?

For adults, two 5ml vials containing fluorescein 10% solution are mixed in a cup with 1-4 ounces of apple juice, orange juice, or sweetened water.  The best images are achieved if the drink is consumed in one gulp.  It is fine to “wash down” the bitter taste with additional beverage of choice.  Using an SLO fundus camera programmed for FA, take one photo per minute for each eye (set timer) until the retinal vessels start to fill.  This is usually about 4-5 minutes from start time.  Once all the vessels fill well, peripheral views may be captured.  Afterwards, one image is captured every 5 minutes until ending the photos 20-30 minutes from the start time.  If the images are not satisfactory, the test may be repeated after an overnight fasting without food.       

How is the fluorescein dosage adjusted by patient weight?

The amount of 10% fluorescein dye may be adjusted downward for patients weighing less than 90 pounds.  This adjustment is especially important for children.  The recommended dosage is 25mg/kg.  As fluorescein dye is supplied in 5ml vials of 10% solution for injection, the table below may be used for dosing by weight in pounds:

By Scott E. Pautler, MD

Copyright  © 2022 Designs Unlimited of Florida.  All Rights Reserved.

What is fluorescein angiography?

Fluorescein angiography is a photographic test using a special camera to take pictures of the retina inside the eye.  A dye is injected into a vein in the arm.  As the dye courses through the retina, many photographs are taken.  These photographs reveal exquisite details of the retina. In patients whose veins are difficult to access, oral fluorescein angiography may be considered.

Why is fluorescein angiography ordered?

After a complete examination of your eyes, the Eye MD may recommend fluorescein angiography to help establish a diagnosis or help to monitor results of treatment.  Very often a fluorescein angiogram helps in choosing the best treatment for a particular condition.  For example, if the Eye MD sees a leakage of fluid in the retina, the fluorescein angiogram will help determine the source of leakage, so that treatment can be directed appropriately.  Similarly, the end of treatment may be determined by repeating the fluorescein angiogram to see if the leakage has been stopped.    

What are the side effects of fluorescein angiography?

Usually after fluorescein angiography the skin turns yellowish for several hours from the dye.  Because the dye leaves the body through the kidneys, the urine will turn dark orange for a day or so.  Alternatively, if you are on kidney dialysis, mention the orange color to the dialysis technician so as to avoid unnecessary concern.  Some people feel nauseated during the procedure.  This symptom passes quickly, and may be avoided next time by injecting a smaller dose of dye more slowly.  If the dye escapes from the vein, you may feel a burning pain at the injection site.  Relief is obtained with an ice-cold compress for several hours.  Notify the doctor if pain occurs or persists at the injection site after twenty-four hours.  Allergic reactions to fluorescein are rare and are usually limited to skin rash and itching, which responds to Benadryl.  Even more rarely, severe allergic reactions can occur at the time of injection and may be life threatening.  This is treated as an emergency in the doctor’s office where equipment is available. Finally, some blood test results are altered by fluorescein if blood is drawn within a day or so after angiography, so you may wish to notify the laboratory.

By Scott E. Pautler, MD

For a telemedicine consultation with Dr Pautler, please send email request to spautler@rvaf.com. We accept Medicare and most insurances in Florida. Please include contact information (including phone number) in the email. We are unable to provide consultation for those living outside the state of Florida with the exception of limited one-time consultations with residents of the following states: Alabama, Arkansas, Connecticut, Georgia, Minnesota, and Washington.

Copyright  © 2019-2022 Designs Unlimited of Florida.  All Rights Reserved