09 Aug Is Your Doctor Watching You With OCT Technology?
Yes, probably he/she is. Your doctor is most likely well trained and highly likely to up-to-date with the latest technology to examine your retina, specifically your macula, for conditions such as macular degeneration, diabetic retinopathy, epiretinal membranes, macular hole, etc.
What is OCT? OCT stands for Optical Coherence Tomography. It is basically a laser used as a scanning to device to examine and image your retina in terrific detail. The test is performed in the office, takes about five minutes and yields a clear, easy to understand 2D or 3D image of the retina and its layers. It does not hurt, nothing touches your eye and requires no injections. Using this “laser interferometry” has several basic advantages:
1. it can provide quick, reproducible, “high definition” images of the surface and subsurface of the retina.
2. it is non-invasive and requires no injection of a test substance, such as the case with fluorescein angiography which may have a few side-effects.
3. there is virtually no “set-up” time, such as obtaining informed consent, installing film (old days), pre-treatment with antibiotics, etc.
What does OCT tell us? There are many indications for obtaining an OCT, but it is extremely useful for following patients with macular degeneration and diabetic retinopathy. In a nutshell, OCT is an excellent way to follow macular edema, or swelling of the macula. The two most common diseases that are associated with macular edema are diabetic retinopathy and macular degeneration.
In patients with diabetes, optical coherence tomography can be used to identify macular edema, or swelling, and serial studies can compare the success of treatment. It may also show thin membranes on the surface of the retina that may be causing some loss of vision.
In patients with macular degeneration, OCT is very useful for diagnosing macular edema related to the “wet” form, or exudative form, of macular degeneration. I find it very useful for determining the need for additional anti-VEGF injections such as Avastin®, Lucentis® or Macugen®. Since it is quick and non-invasive, I prefer it over fluorescein angiography to determine if a patient needs another intra-ocular injection.
What does this mean? OCT gives us the advantage of obtaining detailed information about the macula in cases of diabetic retinopathy and macular degeneration. It is used for other diagnoses, but for the scope of this web site, it has specific indications and advantages over fluorescein angiography. Having said that, fluorescein angiography is not an obsolete diagnostic test. It, too, has unique advantages and many times I find it helpful to employ both tests to help me diagnose and treat a patient.
Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist