If you care about your eye health, you may have heard about OCT scans. But what exactly is an OCT scan? OCT stands for optical coherence tomography. An OCT scan is an advanced eye test that provides incredibly detailed images of the back of your eye, including the retina, optic nerve, and deeper layers.
How does an OCT scan differ from other eye tests?
Unlike a standard eye exam or even retinal photography, an OCT scan shows your eye doctor cross-sectional images, almost like an MRI scan. This allows them to see all the layers of the
retina and optic nerve and detect even the tiniest changes that could indicate early signs of eye disease.
In a traditional eye exam, your doctor might use an ophthalmoscope or take fundus photos to view the surface of your retina. While these methods can show obvious problems, they don’t provide the detailed, 3D images that an OCT scan does.
With OCT, your doctor can see and measure the thickness of individual retinal layers and the nerve fiber layer. This level of detail is crucial for diagnosing conditions that cause gradual changes, like glaucoma. Additionally, OCT scans can often detect problems before you notice any vision changes, allowing for earlier intervention.
What conditions can an OCT scan detect?
OCT scans are an incredibly valuable tool for diagnosing and monitoring many potentially sight-threatening eye conditions and diseases. Some of the major conditions OCT scans help detect and manage include:
- Glaucoma: OCT provides detailed images of the optic nerve and retinal nerve fiber layer, allowing your eye doctor to detect and monitor glaucomatous damage and vision loss.
- Diabetic retinopathy: In diabetic patients, OCT reveals abnormalities in the retinal vasculature and swelling caused by diabetic macular edema. This enables early treatment to prevent vision loss.
- Age-related macular degeneration: Both the dry and wet forms of AMD can be diagnosed and tracked over time using OCT imaging of the macula and retinal layers.
- Macular hole: The incredibly high-resolution cross-sectional OCT images clearly show full-thickness defects in the macula indicative of a macular hole.
- Macular pucker/epiretinal membrane: OCT allows visualization of wrinkles or contractions on the surface of the retina from scar tissue formation.
- Retinal vascular occlusions: OCT can detect compromised blood flow and ischemic swelling from conditions like central/branch retinal vein or artery occlusions.
- Inherited retinal diseases: Many genetic retinal conditions like Stargardt disease have structural changes visible on OCT scans.
By detecting these and other eye problems at an early stage, before significant vision loss occurs, an OCT scan enables timely diagnosis and treatment to preserve your sight and eye health. The detailed imaging provided by OCT has truly revolutionized how eye doctors detect, monitor, and manage vision-threatening retinal diseases.
How does optical coherence tomography work?
The OCT machine uses a low-power laser to scan your eye and capture the reflected light. Advanced software then analyzes this reflected light to form the detailed OCT images, mapping out the retinal layers and optic nerve. The whole OCT scan takes just a few seconds for each eye and is completely non-invasive. You simply look into the OCT device while it scans your eyes.
What are the advantages of OCT scans?
One of the biggest advantages of an OCT scan compared to traditional imaging methods is its ability to show change over time. By comparing OCT scans from different visits, your eye doctor can detect even subtle signs of disease progression.
This is especially important for conditions like glaucoma, where the changes in the optic nerve fibers can be gradual.
What are the disadvantages of OCT scans?
Some key disadvantages and limitations of OCT scans include:
- Limited imaging depth of only 2-3mm, as OCT cannot penetrate deeply into opaque tissues. This limits its use to the anterior eye structures.
- Inability to image through dense obstructions like thick cataracts or vitreous hemorrhages, which can block the light waves.
- Smaller field of view compared to other retinal imaging techniques like fundus photography.
- Increased potential for artifacts from eye movements, blinks, or media opacities which can degrade image quality.
- OCT cannot detect leakage from blood vessels like fluorescein angiography, an important factor in certain eye diseases.
- Higher cost of equipment compared to basic ophthalmoscopy or retinal photography.
- Lack of normative databases for comparison, which is useful for conditions like glaucoma.
How often should you have an OCT scan?
If you have a diagnosed eye condition like glaucoma or macular degeneration, your eye doctor will likely recommend OCT scans at regular intervals to monitor for any changes. Even if your eyes are healthy, many eye doctors now incorporate OCT scans into routine comprehensive eye exams for adults. This helps establish a baseline of your eye health.
What to expect during an OCT scan
If you’ve never had an OCT scan before, you might wonder what to expect. The good news is that an OCT scan is quick, painless, and non-invasive. You don’t need any special preparation or even eye drops in most cases. During the OCT scan, you’ll sit in front of the OCT machine and rest your head on a support to keep it still. You’ll simply look into the device at a target while it scans your eye, capturing detailed images. The whole process usually takes less than 10 minutes for both eyes.
How much does an OCT scan cost?
One common question about OCT scans is the cost. OCT scan cost can vary depending on location and whether it’s covered by your vision insurance plan. In some cases, OCT scans may be an additional charge on top of your routine eye exam. However, many eye doctors believe the benefits of this advanced technology for detecting and managing eye disease make OCT scans a worthwhile investment in your long-term eye health. If cost is a concern, talk to your eye doctor about payment options.
What is the difference between a CT scan and an OCT scan?
A CT (computed tomography) scan and an OCT (optical coherence tomography) scan are quite different imaging techniques:
- CT scans use x-rays to create cross-sectional images of the body, while OCT scans use light waves to take cross-sectional pictures of the retina and front of the eye.
- CT scans can image the entire body, while OCT is specifically designed to examine the eye and its structures like the retina, optic nerve, etc.
- CT scans expose the patient to ionizing radiation from the x-rays, while OCT is completely non-invasive and uses no radiation—just light.
- CT provides images of bones, blood vessels and soft tissues inside the body, while OCT provides incredibly high-resolution images of the microscopic retinal layers in the eye.
Final thoughts
To summarize our article, an OCT scan is a cutting-edge imaging test that uses light waves to capture high-definition, 3D pictures of the back of your eye. What is an OCT scan used for? It allows your eye doctor to see the retina, optic nerve, and other delicate structures in remarkable detail to detect even the earliest signs of vision-threatening diseases like glaucoma, macular degeneration, and diabetic retinopathy.
So, how often should you have an OCT scan? Many experts now recommend annual OCT scans as part of a comprehensive medical eye exam, especially for adults over 40 or those at higher risk for eye disease. By establishing a baseline and monitoring any changes over time, OCT scans give your doctor a powerful way to catch problems early and start treatment promptly.
If you’re looking for an eye doctor in the Milwaukee area who provides advanced OCT scanning and other state-of-the-art optometry services, look no further than 414 Eyes. Our team uses the latest technology like OCT to fully evaluate your eye health and vision needs. We also offer a wide selection of stylish eyeglasses and specialty contact lenses, with an expert fitting process to ensure ideal comfort and vision.
Call 414 Eyes today to schedule your OCT scan and comprehensive eye exam!
