Ocular Coherence Tomography

By Donald C. Bartnick, CMPE, CEO

Maryland Eye Associates

. http://marylandeyeassociates.com

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Ocular Coherence Tomography

Ocular Coherence Tomography, or OCT, as an applied technology, is only about 10 years old. OCT is an advanced technology most frequently used in ophthalmology for retinal imaging and analysis. This technology provides highly detailed images (near microscopic) of the retina as well as the optic nerve. The technology also has cross application in other specialties.

OCT uses light waves to create a cross-sectional image of the retina. The test is noninvasive and can be performed in the ophthalmologist's office. Using specific and known wavelengths of light and sophisticated computer programs, data averaging and data comparisons, the OCT provides the doctor with a color, visual image and data calculations based on the observed transmission of light through the different tissue layers and thicknesses of the retina and optic nerve. The image may be two-dimensional or three-dimensional. Because the equipment uses light waves, there may be situations where the lack of light transmission inside someone's eyes prevents its use.

An OCT test must be ordered and interpreted by the doctor but the test is usually performed by a specially trained ophthalmic technician. Many times, the eyes are dilated to allow better visualization of the interior of the eye. Dilation usually takes from 20-30 minutes. Then the patient sits in front of the OCT machine with his or her head resting on a support to keep it motionless. The machine scans one eye at a time without touching the eye. The scan takes about 10 minutes per eye. The computer analysis is extremely quick and the data may be printed for interpretation by the doctor or may be communicated directly into the doctor's electronic health record system. The image is also saved on the OCT machine and sometimes the doctor may want to look at the image directly on the OCT machine.

An OCT image may be useful to your ophthalmologist in diagnosing or evaluating the severity or progression of diseases such as glaucoma, diabetic retinopathy, age-related macular degeneration, macular edema, macular pucker, macular hole, central serous retinopathy, or multiple sclerosis. Sometimes OCT is used preoperatively and/or post-operatively in cataract surgery. OCT provides information for diagnosis, evaluation of disease progression, and assessment of treatments.
OCT has recently been used in interventional cardiology to help diagnose coronary heart disease and in dermatology to improve the diagnostic process. Even more recently, OCT has been applied for use in oncology to assess cancerous and precancerous lesions.

OCT technology is expensive but extremely useful. Research is moving forward to develop even newer generations of OCT that provides finer detail and even real-time doppler vascular flow analysis. Research is investigating the use of different light wavelengths, lasers and/or pulses as the light source. Other research is using advanced mathematical analysis to extract additional information from the data. OCT is being investigated as providing an in vivo, non-invasive “biopsy” of tissues. Investigational research using the OCT is also considering the impact of treatment modalities (vitamins and drugs) on microscopic tissue structures.

OCT is a new technology with enormous application and potential to provide noninvasive data on the microscopic level. It is in use now and research for improved equipment and applications is ongoing.