Understanding OCT Retinal Scan: A Comprehensive Guide

The Optical Journal states that “vision science” and making optical aids, like eyeglasses, have existed for over 4,000 years. A great deal has changed, including innovations in optometry and ophthalmology.

An OCT retinal scan is a perfect example. The impact of these devices is crucial. They help in the early detection and treatment of eye diseases.

This article explains how OCT Devices work. It also covers their many uses and benefits. Keep reading to determine if these devices and functions might benefit your practice.

What Is an OCT Retinal Scanner?

The American Academy of Ophthalmology says an optical coherence tomography (OCT) scan is safe. Eye doctors use it to look at the parts of the eye, like the retina. “Ocular” means “related to the eye.” “Tomography” is the ability to create 3D images of the inside of an object.

An OCT scan works similarly to an ultrasound. It uses light-based technology to create high-resolution, cross-sectional advanced eye imaging.

Precisely, it measures wavelengths of infrared light that reflect off the retina, located on the back of the eye. This allows doctors and staff to view the eye in layers and measure the depth of important structures.

What Happens During an OCT Retinal Scan?

Several steps exist for performing an OCT exam. The first is that the ophthalmologist will put dilating drops into the patient’s eyes. These widen the pupils, making it easier to examine the retina.

Next, the patient will sit in front of the OCT scanner and rest their head on a supportive platform, which keeps it motionless. The OCT equipment then scans the out without touching it. This typically takes between five and 10 minutes. Computer software then produces the images; physicians use them to diagnose conditions or monitor ongoing treatment.

What Are the Advantages of an OCT Retinal Scan?

Many advantages exist to using an OCT retinal scanner. These include its ability to produce extremely detailed images of the retina’s layers.

This allows doctors to make a more accurate retinal disease diagnosis. It can lead to early detection of various eye diseases (see below), even before typical symptoms arise.

Another advantage of an OCT retinal scan is that it can help monitor the progression of eye diseases. It also allows doctors to gauge the effectiveness of treatment better.

OCT retinal scans are non-invasive. The procedure is painless, safe, and relatively comfortable for most patients.

What Important Eye Components Can an OCT Scan?

The OCT retinal scan examines many intricate structures of the eye. The most common targets of imaging include:

• Macula
• Optic Nerve
• Retinal blood vessels
• Retinal layers

Examining these can be a critical aspect of ensuring eye and vision health. Without innovations like OCT retinal scans, accomplishing this is impossible.

Macula

The macula is a small, oval-shaped area in the center of the eye’s retina. Its main function is to focus light that enters the eye onto the retina. Responsible for central vision, or the ability to process sharp, detailed images. Our vision allows us to read, see colors, drive, and recognize faces.

Optic Nerve

The optic nerve is another crucial part of the eye’s visual system. A bundle of more than 1 million nerve fibers in each eye is a communication link with the brain.

The optic nerve sends electrical signals. These signals carry visual information from the retina’s photoreceptor cells to the brain’s processing centers. Damage to the optic nerve can result in vision loss, blurred vision, and blind spots.

Retinal Blood Vessels

The retina comprises a complex network of cells and blood vessels. These are integral to proper vision. Three main types of retinal blood vessels exist:

• Central retinal artery
• Central retinal vein
• Capillary network

The central retinal artery is the main artery that supplies blood to the inner layers of the retina. It branches into a network of smaller vessels that reach retinal cells.

The central retinal vein is the main vein that drains blood from the retina, returning it to the heart and lungs for reoxygenation. The capillary network is the dense lattice of blood vessels within the retina.

These three types of blood vessels are important for providing the retina with oxygen and nutrients. You need these for proper function. They also remove waste products from the retina.

Retinal Layers

The retina itself is a complex, multi-layer structure. As mentioned, it converts light into electrical signals that the brain interprets as vision. This is accomplished through the myriad functions with distinct layers, which include:

• Nerve fiber layer (NFL)
• Ganglion cell layer (GCL)
• Inner plexiform layer (IPL)
• Outer plexiform layer (OPL)
• Inner nuclear layer (INL)
• Outer nuclear layer (ONL)
• Photoreceptor layer
• Retinal pigment epithelium (RPE)
• Choroid

The NFL and the GCL contain nerve fibers and cells that transmit visual signals from the retina to the brain. The IPL and the OPL consist of layers of synapses that transmit signals between neurons. The INL and ONL contain cell bodies of neurons and photoreceptor cells involved in visual processing.

The photoreceptor layer of the retina has light-sensitive cells. These cells change light into electrical signals. The RPE is a layer of cells that feeds the photoreceptor layer. The choroid is a layer of blood vessels that supplies blood to the outer layers of the retina.

The OCT scanner can show these structures clearly. It gives important information about the retina’s health and function. It also can detect, diagnose, and manage various eye diseases affecting these layers.

What Are Common Conditions an OCT Retinal Scan Detects?

Doctors use OCT retinal scans to diagnose myriad diseases and conditions. Common ones include:

• Age-related macular degeneration (AMD)
• Macula Edema
• Diabetic retinopathy
• Glaucoma
• Retinal detachments
• Retinal vein occlusion

Age-Related Macular Degeneration 

AMD is a common eye condition that affects central vision. This can make it difficult for affected persons to read, drive, recognize faces, and perform other tasks. Symptoms include:

• Blurred central vision
• Straight lines appearing wavy or distorted
• Dark spots
• Difficulty adjusting focus to low light

Two types of AMD exist. Dry AMD is the most common type, and it involves the gradual breakdown of light-sensitive cells in the macula. Wet AMD causes abnormal blood vessels to grow under the macula. This can release fluid and blood, harming central vision.

No cure exists for AMD. Patients can do many things to slow its progression. This makes early detection by an OCT retinal scan crucially important.

Macula Edema

Macular edema refers to a swelling of the macula. This happens when fluid builds up in the macula, causing the retina to thicken and swell.

This distorts the macula’s shape and interferes with how light focuses onto the retina. It can lead to blurred and distorted central vision, dark spots, and diminished color vision.

Causes of macula edema include AMD, diabetic retinopathy, and retinal vein occlusion. Other triggers also exist. These include inflammation, eye surgery, and certain medications.

Different treatments for macula edema can relate to the causes. These include medications, laser therapy, and steroid injections. Detection and monitoring are pivotal, making OCT scanners a vital tool in treatment.

Diabetic Retinopathy

Diabetic retinopathy is a serious eye condition that affects people with diabetes. It occurs when high blood sugar levels weaken or damage tiny blood vessels in the retina.

Sometimes, the body attempts to compensate for damaged blood vessels by growing new ones. These vessels are often fragile, leading to leaks and related blood and fluid buildup in the retina.

Nonproliferative diabetic retinopathy refers to the early stages of the disease. It can be mild, moderate, or severe.

Proliferative diabetic retinopathy is a more advanced stage, where major symptoms are serious. These include blurred vision, “floaters” (spots or dark specks in vision), and difficulty seeing at night.

Treatments that limit the impacts of diabetes on the body, including the eyes, can control diabetic retinopathy. Regular eye exams that include an OCT scan also can help monitor and determine appropriate treatments for the condition.

Glaucoma

Glaucoma is a category of eye disease that damages the optic nerve, which transmits visual information to the brain. Increased pressure inside the eye, or “intraocular pressure,” characterizes it. Left untreated, glaucoma can lead to partial or total vision loss.

Three main types of glaucoma exist:

• Open-angle glaucoma
• Angle-closure glaucoma
• Normal-tension glaucoma

Open-angle glaucoma is the most common type. It results from slow drainage from the eye, causing pressure buildup.

Angle-closure glaucoma is a less common but more serious type. In this condition, something blocks the drainage angle of the eye. This blockage leads to sudden and severe pressure in the eye. Normal-tension glaucoma refers to optic nerve damage that is unrelated to eye pressure.

Often, no early symptoms of glaucoma exist. Blurred vision and gradual vision loss (from peripheral to central vision) are two. Eye pain and headaches are other common symptoms.

Early detection and treatment are critical for managing glaucoma and preventing vision loss. OCT for Glaucoma can play a crucial role in detecting and treating the onset of glaucoma.

Retinal Detachments

Retinal detachment is another common condition an OCT retinal scan can detect and help treat. This happens when the retina pulls away from the tissue below it. This shift makes it hard for the retina to turn light into images. A serious medication condition can lead to permanent vision loss if left untreated.

Retinal detachment is often a result of eye injury, but there are other causes. Nearsightedness, for instance, makes it more likely.

The jelly-like substance called “vitreous” inside the eye can shrink as we age. It may also pull away from the eye. This can create a tear and result in retinal detachment.

Symptoms include floaters, flashes of light, and blurred vision. Loss of peripheral vision is another common side effect. OCT retinal scans can better diagnose these conditions and help doctors formulate solutions. 

Retinal vein occlusion

Retinal vein occlusion (RVO) refers to a blockage in the veins that carries blood away from the retina. These can be in large or small veins, leading to various symptoms, including blurred vision and floaters. Common causes of retinal vein occlusion include:

• High blood pressure
• Diabetes
• Glaucoma
• Increased blood viscosity
• Atherosclerosis (hardening of the arteries)

Doctors usually treat RVO with medications or laser therapy. However, close monitoring may sometimes be sufficient to ensure the condition does not worsen. OCT retinal scanners can be a vital tool in this endeavor.

Are There Any Downsides to an OCT Scan?

A few downsides exist to getting an OCT scan. One is that it works most effectively when the eyes dilate. This is a small problem. It can be uncomfortable, making driving or working for a few hours hard.

Another potential negative is cost. OCT scans can be expensive. This could weigh heavily on using the technology for patients lacking health insurance.

Finally, OCT scans may not be suitable for all patients. In some cases, like with cloudy corneas, OCT scans might not work. The image quality may also be poor. An experienced optometrist or ophthalmologist can determine the appropriate uses.

Find Quality OCT Retinal Scanners for Your Practice

Now that you know how an OCT retinal scan works, you can decide if it is the right tool for your practice. A reputable retailer can further advise you on different configurations and available options.

Saturn Optical is the world’s largest supplier of optometric and ophthalmic products for hospitals, clinics, and doctors’ offices. We take pride in carrying only the best quality equipment and supplies. We also offer top-notch customer service.