“It’s a computerized tool. Optical Coherence Tomography (OCT) is a very detailed non-contact eye scan. The first opinion was based on an abnormal OCT reading, but another OCT scan was normal. Seeing how much tissue is lost in the retinal nerve fiber layer helps him determine how aggressive he needs to be. Greg Hoffmeyer, BFA, CPT, manager of research imaging, Duke University Eye Center and senior technical analyst at the OCT Reading Center, Duke University. Optical coherence tomography (OCT) is a noninvasive imaging technology used to obtain high-resolution cross-sectional images of the retina. Optical Coherence Tomography (OCT) Optical Coherence Tomography (OCT) is a non-invasive diagnostic instrument used for imaging the retina. With OCT, your ophthalmologist can see each of the retina’s distinctive layers. We need to hold imaging data to the same standards that we hold other testing data—reproducibility and reliability.”. Working in a similar way to an ultrasound, the OCT eye test emits light waves to create high definition pictures of the structural layers beneath the retina. It is used for medical imaging and industrial nondestructive testing (NDT). There are no side effects to the test itself, in some instances, your eye may have to be dilated to take it. But if the OCT reveals a large optic nerve head in a patient with a very thin nerve fiber layer, that incongruence might suggest an abnormality. He’s more aggressive in patients with thinner nerve fiber layers. W. Drexler, in Encyclopedia of the Eye, 2010. OCT reveals details that have never been seen with the ophthalmoscope. In the standard eye chart test, you are asked to cover one eye and read as may lines of texts on the eye chart as possible. A laser scans the eyes from behind a wall of glass and this produces digital images of the retina. Here is what the experts advise on getting the most from OCT. Rohit Varma, MD:“If it’s not good quality, and you think you have a good chance of getting a good image, then repeat the OCT. We do repeat testing for visual fields. Glaucoma imaging project. Following are some ways these ophthalmologists are fitting OCT into their practices. Eye field test and tomography showed that my eye nerves are healthy but scotomas are floating in my left eye(hardly noticeable)Will they get bigger? This will gauge your visual acuity and also help determine whether you are nearsighted (myopia), farsighted (hyperopia) or possibly have astigmatism. I am a 64 years old man who had an eye test done recently, which indicated no evidence of diabetic retinopathy in my right eye. There is a type of glaucoma called normal tension glaucoma where the eye pressure measu ... is state of tension, apprehension, worry, uneasiness or fear. hydroxychloroquine is on the eye. Decreased OCT image quality can be attributable to cataracts which block light, patient motion artifact, or any other media opacity. What is this test for? You just don’t want it to be your only tool,” he said. Moya finds nerve fiber layer images useful in setting target pressures. You may also try artificial tears such as Refresh, Systane, Soothe, Opteve, etc. As Dr. Schuman put it: “For progression, I wouldn’t trust OCT in a vacuum.” On the other hand, his group has shown that more progression events were detected with OCT than with perimetry over a six-year period.1 “That means OCT is more sensitive to progression, but we don’t know about the specificity.”, Still, OCT can be useful if it shows a progression event that also appears on a visual field, Dr. Schuman said. While Dr. Moya finds the nerve fiber analyzer thickness scan most useful, he also uses the macular and optic nerve scans. Because I did have an abnormal VEP in my right eye, he therefore declined to order an OCT test. But you don’t know for sure how well this relates to future changes in visual field or the patient’s vision,” said Dr. Huang, AIG principal investigator. Talk to your doctor if you are worried. However, OCT is … “Not every OCT is a revelation. “One has to use retinal thickness measurements carefully and make sure they make sense in the overall clinical context.”. But “OCT images are so intuitive that most patients will understand what I’m talking about when I show them the images,” Dr. Ip said. A new, long-term study sponsored by the NEI—the Advanced Imaging for Glaucoma (AIG) project—may definitively answer questions about the relevance of new imaging technologies. Financial interests: None. “I have found that larger optic nerves have correspondingly thicker nerve fiber layers, as the testing occurs closer to the optic nerve, where we know the nerve fiber layer is thicker,” he said. “Future improvement in speed, resolution and image processing will make the results more robust. Optical coherence tomography may not be as pervasive as the ophthalmoscope, but it has definitely gone mainstream. Optical coherence tomography – or OCT – is a medical imaging technique. Make sure you have a pair of sunglasses to wear after the procedure and be sure you have someone to drive you home. Each test during an eye exam evaluates a different aspect of your vision or eye health. To take the test, I peered into a hole in the side of the Optomap machine. “Comparing OCT to angiography now is like comparing a 2-D sonar image to an aerial satellite image of the ocean. What is OCT test? “The thing that people have been looking for in glaucoma is the one machine that will say, ‘Yes glaucoma,’ or ‘No glaucoma,’” said Dr. Moya. It is an addition to our armament of diagnostic tools.”. “Fluorescein is more of a functional assessment, while OCT is more of an anatomic assessment,” Dr. Ip said. Any Signal Strength 7 and higher is considered acceptable. Inspecting the drainage angle (gonioscopy) Keep the surface of the cornea moist. Due to the transparency of the eye (i.e. Your experience with OCT is unusual but may also be a result of the stress of the testing, your original symptoms and your stress over what might be causing your symptoms. Financial interests: None.Joel S. Schuman, MD, professor and chairman of ophthalmology, University of Pittsburgh, director of University of Pittsburgh Medical Center Eye Center. 3 Zangwill, L. M. et al. But OCT is not a magic bullet, and it cannot stand alone. Though there are nerve fiber layer progression analyses that compare to baseline readings, he said he can’t be sure that the same tissue is being measured on follow-up exams. He regards OCT as “quite an advance from when we just had fluorescein angiography and fundus photography. OCT is an abbreviation of Ocular Coherence Tomography. The test on its own does not use x-ray technology and therefore does not present radiation risks. OCT utilizes a concept known as inferometry to create a cross-sectional map of the retina that is accurate to within at least 10-15 microns. Although not all of these side effects may occur, if they do occur they may need medical attention. After field exam and tomography i was diagnosed scotoma in the left eye. Dr. Moya finds OCT most useful with glaucoma suspects who may not have obvious field defects on standard perimetry. He or she may perform several tests, including: 1. It also shows the anatomical changes that can occur in a way that fluorescein angiography does not. He tends to be less aggressive in patients with a significant amount of cupping but who still have a good amount of nerve fiber tissue left. It is also useful in many different types of retinal disease. Measuring corneal thickness (pachymetry) 5. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. But this can pose health risks, especially if repeated. He can’t do this with fundus photographs or angiography. OCT scanning uses light waves to take cross-section images of the back of the eye (the retina). Retinal thickness measurements. There's lots of buzz around OCT, but what are its uses in practice, and when should you stick with older, tried-and-true methods of imaging? It is also useful in many different types of retinal disease. Dilate the pupil. One of the glaucoma test side effects associated with the physical examination of the eye is that of blurred vision and light sensitivity. Taking high doses (600 mg per day) of . The largest arm of the five-year study follows glaucoma suspects and preperimetric glaucoma patients to test the hypothesis that advanced imaging can detect glaucoma progression prior to visual field and optic disc photography. This happens because the pupil is artificially dilated using special eye drops. Unless that is the case, they should disregard the interpretive data. But the report showed juxtafoveal telangiectasis, foveal reflex dull. Arch Ophthalmol 2005;123:1188–1197. Financial interests: Receives a royalty for the OCT systems now being sold, and gets research support from Carl Zeiss Meditec Inc. Michael S. Ip, MD, associate professor, University of Wisconsin, Fundus Photograph Reading Center. The maps can be very accurate when [you are] looking for things such as retinal thickening from edema. It has the ability to detect problems in the eye prior to any symptoms being present in the patient. Optical coherence tomography (OCT) is a rapidly emerging noninvasive diagnostic imaging modality enabling in vivo three-dimensional (3D) visualization of tissue microstructure. Similar to a CAT scan, the OCT uses infrared light rather than x-rays to form a cross-sectional view of your retina. 1-3 OCT-A can be performed even when not medically necessary and can be safely performed in circumstances when FA is contraindicated. OCT measures the retinal nerve fiber layer thickness in glaucoma and other diseases of the optic nerve. “We still need more experience to know when you see a defect on these imaging tests, whether it’s an artifact or correlates with visual field loss now or in the future.” Dr. Huang is associate professor of ophthalmology, University of Southern California. This usually returns to normal even when you continue taking the tablets. However, we have recently seen two cases of dry eye syndrome associated with Accutane therapy that have persisted for more than two years. Included are the latest generations of advanced imaging instruments: optical coherence tomography (OCT), scanning laser polarimetry (GDx) and scanning laser tomography (HRT). Modern ct scanners should minimize radiation exposure b ... My eye doctor wants to do an Optic Coherence Tomography test. 4 Ko, T et al. Ophthalmology 2005;112:1922–1935. Arch Ophthalmol 2004;122(6):827–837. Checking for areas of vision loss (visual field test) 4. They are both images of the ocean but offer two different types of information,” Mr. Hoffmeyer said. “But if I see thinning of the nerve fiber layer superiorly, and see a corresponding decrease in the macular volume superiorly, that makes me feel more comfortable that I’m observing a true defect in that area.”. OCT Eye Test Explained. “So people would look at these printouts and say, ‘Ah, it’s all green; it’s fine.’ Or, ‘It’s red; we need to operate.’” But if the data are unreliable, the physician can make a wrong decision, he said. Dr. Schuman agrees. For more information, call the toll-free number 866-450-6782 or e-mail aigs@usc.edu. Are there side effects? “You just know that there is some anatomic problem.”, But Dr. Huang said the study could lead to better understanding of how to interpret the images generated by these devices. Current research with ultrahigh-resolution OCT is expected to offer even better images than standard-resolution OCT.4 Dr. Huang predicts that improved hardware and software will lead to “amazing advances” with this technology. JCH MD Photographers, he explained, are still learning how to image the layers of the retina properly, and physicians are learning how to interpret the information. “OCT represents a major advance in ancillary testing as it relates to retinal diagnoses.”. Lately, however, Mr. Tyler has seen a trend back to fluorescein angiography, which he said is useful for establishing the location of the pathology. This article is from November/December 2005 and may contain outdated material. OCT cocreator David Huang, MD, PhD, agreed that we don’t yet know whether all the OCT measurements are reliable. It can be used in glaucoma to measure the size of the angle and to measure the thickness of the layer of tissue around the optic nerve. Can confuse progression? Optical coherence tomography (OCT) was only recently approved for use in the United States, but its use in Europe has demonstrated minimal risk for patients. Blurred vision may occur in the first few weeks . By using our website, you consent to our use of cookies. The doctor advised optical coherence tomography (OCT) test for both the eyes. It is quick and painless, nothing touches your eye at all - it is just like having an x-ray taken and takes a few seconds additional to your usual eye test. OCT is useful for helping to buttress a diagnosis, he said. It’s not an eye doctor,” Mr. Hoffmeyer said. “We have not plateaued in our ability to determine what’s the best way to use OCT. There’s still so much more to learn.” Still, Dr. Moya uses OCT on all his glaucoma suspect and glaucoma patients. When one worried patient came to Dr. Varma for a second opinion after being told he needed surgery, Dr. Varma found no evidence of glaucoma damage. OCT is useful for red-flagging the optic nerve head. “It’s one more important tool in your armamentarium. OCT, for example, cannot tell if choroidal neovascularization is classic or occult, cannot gauge circulation for vascular occlusion studies and cannot show tissue perfusion or nonperfusion. But OCT is the newest of the technologies and may be on track to become the most widespread. Signal parameters pertain to the quality of the laser signal that was collected from the eye at the time of imaging. In addition, OCT is noninvasive and can help diagnose and manage a variety of retinal diseases, as well as glaucoma. Patient education. Because OCT can detect the vitreoretinal interface with good resolution, it makes it easy to document and follow conditions such as epiretinal membranes and secondary thickening. Dr. Varma contends that doctors must check that the signal parameters are in an acceptable range. OCT is also helpful in distinguishing macular holes from lesions such as epiretinal membrane with a pseudo hole, and it can readily identify stage one macular holes, Dr. Ip said. With AMD patients, for example, OCT is good at detecting subretinal fluid and differentiating it from increased retinal thickness. Optic nerve head analysis. Optical coherence tomography is a non-contact, high-resolution, in vivo imaging modality. OCT uses light waves to take cross-section pictures of your retina. Check with your doctor or nurse immediately if any of the following side effects occur while taking colistimethate: Setting target pressures. Very rarely, OCT can cause complications such as arrhythmia (abnormal heartbeat) or blockage, dissection or spasm of the artery. Written By: Miriam Karmel, Contributing Writer, Instruction Courses and Skills Transfer Labs, Program Participant and Faculty Guidelines, LEO Continuing Education Recognition Award, What Practices Are Saying About the Registry, Provider Enrollment, Chain and Ownership System (PECOS), Practice Forms Library - Job Descriptions, MIPS Solo and Small Practice Survival Guide, 2020 MIPS Payments: Understanding Remittance Advice Codes, Final Checklist for EHR/Non-EHR 2019 MIPS Reporting, Subspecialty/Specialized Interest Society Directory, Subspecialty/Specialized Interest Society Meetings, Global Programs and Resources for National Societies, Dr. Richard Mills' Opinions, 2002 to 2016, International Society of Refractive Surgery. He is now working with a prototype that is 73 times faster than the current model and should provide more detailed anatomic information for both glaucoma and retina applications. According to Dr. Varma, some eye care providers are making treatment decisions based on overly simplified, and often unreliable, interpretative information generated by OCT (and other optic nerve imaging devices, too). Some side effects of ocular lubricant ophthalmic may occur that usually do not need medical attention. Optical Coherence Tomography (OCT) is a non-invasive diagnostic technique that renders an in vivo cross sectional view of the retina. Frank J. Moya, MD:“Early on, the physician needs to take the time to see how the test is being done and do some quality control and be sure the tests are being completed in a proper fashion.”, Michael S. Ip, MD:Sometimes you can keep retaking a scan and get an artifact. “The OCT is an excellent way to visualize the different layers of the retina and optic nerve in a living eye. Don’t forget to look at the patient. Is it necessary to test it urgently? Rather than pit OCT against angiography, ophthalmic photographer Greg Hoffmeyer, BFA, CPT, prefers to regard them as complementary tools. There’s no reason not to, said Dr. Schuman. Previous to these amazing technologies we were only able to see this view of an eye with tissue sections after the patient was deceased or if the eye was removed. What is OCT? Your eye doctor may use a variety of instruments, shine bright lights directly at your eyes and request that you look through an array of lenses. Because of that uncertainty, he’s not likely to change the course of therapy, or to initiate therapy, based on a possible progression noted on OCT. Dr. Varma shares that concern. And so was the clinical eye exam. 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