What is retinal imaging?
Retinal imaging uses technology to capture high-resolution images of the eye. It provides details that aren't visible through a standard examination. This helps doctors detect and manage eye diseases and scan for broader health issues.
Specialized cameras or scanners are used to capture images of:
- The retina, the light-sensitive tissue at the back of the eye
- The macula, the part of the retina responsible for sharp central vision
- The optic nerve, which sends visual signals to the brain
- The eye’s blood vessels and blood flow
These images can reveal subtle or even microscopic changes in the eye. This can significantly improve the level of care that doctors can provide.
Retinal imaging can enhance patient care in several ways:
- Early detection – Identifying eye diseases in their early stages allows patients to begin treatment earlier, decreasing the risk of vision loss.
- Disease monitoring – Tracking the progression of a disease allows doctors to see how a treatment is working. This information can help them adjust medication or dosages.
- Communication and education – Findings can be more easily shared with patients and other health care professionals.
What can a retinal screening detect?
Retinal scans can help identify issues before symptoms arise. This makes them essential for early intervention. Early treatment for many sight-threatening eye diseases can potentially save vision.
Diabetic Retinopathy
Diabetic retinopathy occurs when high blood sugar damages retinal blood vessels in people with diabetes, causing leaking or swelling. If left untreated, these damaged blood vessels can lead to complications, impairing vision.
Artificial intelligence (AI)-driven tools have been developed to examine retinal scans and help automate screening. These tools look for signs of diabetic retinopathy, such as:
- Microaneurysms
- Retinal hemorrhages
- New, abnormal blood vessel growth
This use of AI could reduce the need for immediate interpretation by a specialist.
Glaucoma
Glaucoma is a condition that damages the optic nerve, often due to increased eye pressure. Imaging can track changes in the optic nerve’s shape or thickness and damage to the retina’s nerve fiber layer. Doctors are then able to assess whether current medication is effective.
Macular degeneration
Age-related macular degeneration (AMD) affects the macula, the central part of the retina. This is the part that is responsible for detailed vision. Scans can reveal drusen (tiny deposits) or fluid under the macula, which can cause blurry or reduced central vision.
Optical coherence tomography angiography (OCTA) is a retinal scan that maps blood flow in these areas. It can be performed without invasive dye injections.
Retinal detachment and tears
Retinal detachment is a medical emergency. It occurs when the retina peels away from the underlying layer that supports it with nutrients. Ultrasound imaging can detect a retinal detachment even if the eye’s lens is cloudy, such as in cataract patients.
Your eye doctor might also detect a retinal tear before it leads to a detachment. To prevent further damage, they can use a laser or a freezing device to seal the tear.
Changes in the blood vessels of the eye
Retinal blood vessels reflect overall cardiovascular health. Narrowed arteries or unusual branching patterns can also help detect:
- Hypertensive retinopathy – Changes in the retina due to high blood pressure
- Vascular changes – Damage to the blood vessels in the retina, showing changes that are happening in the blood vessels in the brain
- Retinal vein occlusion – Blockage of blood flow in the retinal veins that causes vision loss
Tumors
Tumors can be detected with OCT and widefield retinal imaging. High-resolution and cross-sectional images of the retina allow earlier detection and treatment.
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Retinitis pigmentosa
Retinal imaging technology is very helpful in diagnosing and monitoring retinitis pigmentosa (RP). This is a progressive inherited disease. It causes the light-sensitive cells in the retina to deteriorate gradually. People with RP often first notice they have trouble seeing at night. Over time, their side vision and sometimes even central vision can be affected.
Digital retinal imaging during an eye exam
If you’ve had an eye exam recently, there’s a good chance you’ve had a digital retinal scan. This quick and affordable form of retinal screening has become a staple in eye doctors’ offices across the United States.
These retinal imaging devices use special technology to photograph a wide view of the inside of your eye. The image has a detailed view of the retina, optic nerve and retinal blood vessels. The process is quick and painless and doesn’t have any side effects.
A dilated eye exam is one of the best ways for the doctor to see the whole retina. Digital retinal imaging can also be a very useful additional test. The images are immediately available for the doctor to review, allowing them to assess the findings at the same visit.
Some eye care professionals bundle digital retinal imaging into the overall fee for a comprehensive eye exam. But it is more likely to be billed separately. In our nationwide eye exam cost survey, we found that eye doctors charged an average range of $25 to $50 for a digital retinal scan.
Retinal imaging tests and devices
Retinal imaging allows doctors to see details that might not be visible during a regular eye exam. These images are taken using specialized equipment. Each device has a special purpose, from capturing views of the retina’s periphery to creating detailed maps of its layers.
Optomap (ultra-widefield imaging)
Optomap is a type of ultra-widefield retinal eye scan. This type of imaging can capture over 80% of the retina in a single image, providing a thorough view of the retina.
One of the most common retinal screening devices is Optos’ optomap, which provides a 200-degree view of the retina. This type of digital imaging can be used for the everyday patient and is often offered with a comprehensive eye exam. The optomap can be used to detect peripheral retinal issues such as tears.
Other retinal tests are more specialized for diagnosing and monitoring specific eye conditions. They are usually performed by a retina specialist.
Optical coherence tomography (OCT)
Also called OCT, optical coherence tomography is a common imaging technique. It uses light waves to take cross-sectional images of the retina. These images are then used to create a 3D map of the retina’s layers and measure their varying levels of thickness. OCT can also help detect changes in the optic nerve.
Eye doctors may use OCT to detect, diagnose or monitor numerous conditions, including:
- Age-related macular degeneration and other problems with the macula
- Glaucoma
- Diabetic eye problems
- Multiple sclerosis
Optical coherence tomography angiography (OCTA)
Optical coherence tomography angiography (OCTA) is a safe, non-invasive eye imaging test. It lets doctors see blood vessels in the retina without injections or dyes. The test works by taking rapid, detailed scans of the eye. These images detect blood movement, creating 3D maps of tiny blood vessels in the retina and choroid (the layer beneath the retina).
These images help detect early signs of eye diseases such as:
- Diabetic retinopathy
- Glaucoma
- Macular degeneration
Unlike older methods that use fluorescent dyes, OCTA is quicker and painless. It also avoids risks like allergic reactions, making it easier to monitor eye health over time.
Ocular ultrasound
Ultrasounds use “silent” sound waves to get a real-time view of the inside of your eye. They can be particularly useful when there is bleeding inside the eye. This bleeding can make it difficult for an eye doctor to spot the signs of retinal detachment, tears or other retinal conditions.
Two different scans — an “A-scan” and a “B-scan” — can be used to get different information about the retina and other tissues inside the eye. An ocular ultrasound is particularly useful when cataracts or other cloudy areas in the eye prevent a clear view of the retina.
Fundus photographs
Fundus photography involves taking pictures of the back of the eye, including the retina, optic disc and blood vessels. It can be useful for capturing high-magnification images of the retina. This can help document the progression of retinal conditions such as diabetic retinopathy.
Fluorescein angiography
Fluorescein angiography is a test that involves injecting dye into the bloodstream. Images of the retina are then taken to highlight leaking or damaged blood vessels. It is usually used to monitor the retinal effects of diabetes, hypertension or macular degeneration.
Be careful not to confuse a fluorescein angiography with a fluorescein stain test. The stain is a way of detecting a scratched cornea or other issues on the front surface of the eye.
Retinal imaging vs. dilation
Two standard methods are used to check the health of your eyes: dilation and retinal imaging. Retinal imaging can be very useful for routine screenings and monitoring eye conditions. Dilation remains the gold standard for comprehensive exams and complex eye conditions.
Dilation involves using special drops to widen the pupils, allowing doctors to see more of the eye's interior. Dilation can cause temporary blurred vision and sensitivity to light. However, it provides a wide view of the eye, especially the outer edges. This is crucial for detecting serious issues like retinal tears or detachment.
Retinal imaging uses advanced cameras to take detailed pictures of the back of your eye without needing to widen your pupils. This method is quick, comfortable and doesn’t cause blurry vision afterward.
Retinal imaging is an excellent option for routine checks. It can also help monitor the progression of eye conditions. Some of these conditions include diabetic retinopathy or macular degeneration. It allows your eye doctor to keep digital records of your condition.
LEARN MORE: What is eye dilation, how is it done and why?
Schedule an appointment with your eye doctor
Comprehensive eye exams ensure that retinal conditions are diagnosed and treated as early as possible. Contact your eye doctor for more information about scheduling an exam. They can discuss with you which retinal screening options and eye tests are the most appropriate for your eye and medical conditions.
