Digital Retinal Imaging

Normal retina. UHB Trust

Digital retinal imaging is fast becoming an additional part of having an annual wellness eye examination. Next time you check in to your optometrist's office for your routine vision exam, chances are you will be given a form to select yes, or no, to agree to have an additional test that many eye doctors are now performing as an enhancement to their comprehensive eye examination.

What is digital retinal imaging?

With the advent of digital photography, the eye care industry now produces digital retinal cameras that produce an amazing view of the inside of the eye.

Digital retinal imaging, DRI for short, is the act of taking a digital photograph of the inside of the eye including the retina, optic nerve, macula and blood vessels. This image is used to screen for eye diseases and can be used to compare to images taken in future examinations. If a condition or disease is found, the doctor will repeat the test with a higher resolution and higher quality test, called fundus photography. Routine digital retinal imaging is usually performed at a lower resolution for screening purpose and serves as a baseline test.

Does this test cost extra?

Yes, vision care plans and health insurance plans do not cover routine retinal screening. Most eye doctors charge a nominal fee that ranges from $15-$50. However, the test provides additional information to make sure your eyes are healthy.

Doesn't the doctor look inside my eye as part of the examination?

There are differences between a routine vision screening exam and a comprehensive medical eye examination.

Most examinations include a part of the examination where dilating drops are instilled into the eye. This causes the pupil to enlarge so the doctor can look into your eye. However, it is difficult to see the entire retina and sometimes, due to small pupils or patient cooperation, it is difficult for the optometrist or ophthalmologist to visualize everything he or she needs to see.

Digital retinal imaging provides a different way of viewing the retina that sometimes gives the doctor clues about certain eye conditions. Some of these subtle changes can be better seen by digital retinal imaging. Depending on the type of instrument used, digital retinal imaging provides a better view of the retinal periphery.

Does this test mean I don't have to have my eyes dilated?

No. Physically looking into the eye is still invaluable. However, using digital retinal imaging provides different types of information. Combining both allows the eye doctor to make a better health assessment.

What type of machine is used to perform digital retinal imaging?

There are basically three different types of machines that can perform digital retinal imaging. Each one provides a unique view of the inside of the eye and each one uses a different technique to obtain the images. There are advantages and disadvantages to all three methods.

  • Fundus Cameras - Digital fundus cameras are available by several manufacturers. They produce a 45-degree view of the retina. Although the field of view is only 45 degrees, fundus cameras give the highest resolution images available.
  • Optos UWF (Ultra-wide field imaging) - Optos uses a special patented technique that allows up to a 200-degree image of the retina to be seen without using any special dilating eye drops. Optos UWF instruments are very popular among eye doctors. Although technically it does not replace dilating the eye during an examination, some doctors feel that it does just as good a job without the inconvenience of dilating drops.
  • Centervue's Eidon - Centervue's Eidon uses a true color confocal scanner. It can take a 60-degree image in a single exposure but can provide a much larger view with additional functionality, combining up to seven different images for a 110-degree view. The Optos provides a wider field of view, but the Eidon instrument provides better resolution and color.

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