2. What is Optical Coherence Tomography?
• First thing we need to know is what is Optical Coherence Tomography?
• Optical coherence tomography or OCT is a non-invasive imaging test.
• OCT uses light waves to take cross-section pictures of your retina.
• The OCT allows for detection of other diseases such as macular holes,
hypertensive retinopathy and even optic nerve damage.
3. What is Optical Coherence Tomography?
• Tomographic imaging is demonstrated in vitro in the peripapillary area of
the retina and in the coronary artery, two clinically relevant examples that are
representative of transparent and turbid media, respectively.
4. What is Optical Coherence Tomography?
• With OCT, your doctor can see each of the retina’s distinctive layers. This
allows your ophthalmologist to map and measure their thickness. These
measurements help with early diagnosis of some of the major eye problems
that can lead to blindness or disappearance of eye sight
6. Technology use for OCT
• TIME DOMAIN VS SPECTRAL DOMAIN
• TIME DOMAIN
• From its inception, OCT images were acquired in a time domain fashion.
Time domain systems acquire approximately 400 A-scans per second using 6
radial slices oriented 30 degrees apart. Because the slices are 30 degrees apart,
care must be taken to avoid missing pathology between the slices.
7. Technology use for OCT
• SPECTRAL DOMAIN
• Spectral domain technology, on the other hand, scans approximately 20,000-
40,000 scans per second. This increased scan rate and number diminishes the
likelihood of motion artifact, enhances the resolution and decreases the
chance of missing lesions. Whereas most time domain OCTs are accurate to
10-15 microns, newer spectral domain machines may approach 3 micron
resolution. Whereas most time domain OCTs image 6 radial slices, spectral
domain systems continuously image a 6mm area. This diminishes the chance
of inadvertently missing pathology.
8. Uses of Optical Coherence Tomography
• Optical coherence tomography has the ability to detect problems in the eye
prior to any symptoms being present in the patient.
• It examine the health and condition of the patients eye on point and
accurately
• It helps the doctors to see a cross section or 3D image of the retina and
detect the early onset of a variety of eye conditions and eye diseases.
11. Step by step process for OCT
• Step 1) To prepare you for an OCT exam, your ophthalmologist may put
dilating eye drops in your eyes. These drops widen your pupils, it is necessary
to make it easier to examine your retina
• Step 2) You will sit in front of the OCT machine and rest your head on a
support to keep it motionless.
• Step 3) Patient must look the fixation light inside the OCT machine after the
patients head is still and motionless
12. Step by step process for OCT
• Step 4) The equipment will then scan your eye without touching it. If
your eyes were dilated, they may be sensitive to light for several hours after
the exam.
• Step 5) The laser scanner must fix in the center of the eye for more accurate
result. Scanning takes about 5 – 10 minutes.
• Step 6) After the scanning process you may now see the output or the result
of the scan and the doctor can read the result if you need have a healthy or
unhealthy eyes.
13. Tips for better image result in OCT
• 1) Eyes must be still. Eye movement artifacts are one of the biggest issues with
OCT,
• 2) Fundus skills are a good start. Being proficient in taking fundus photographs
can be helpful when learning to work with OCT imaging.
• 3) The Images Don’t Take Themselves.
• 4) Comparing old images to new. Another limitation to current OCT technology
is that the software doesn’t allow us to simultaneously view the acquired images
from previous examinations with the current image on the screen,
