Swept Source OCT vs. Spectral Domain OCT: Unveiling the Differences

Swept source OCT and spectral domain OCT are two emerging technologies in the field of healthcare. Both technologies are implemented for advanced imaging techniques in ophthalmology. Although, both technologies have similar purposes, but differ in application and other technical aspects. Understanding these differences will help us in better implementation of these two technologies. 

Today, we are going to study these differences and understand which one is better for advanced imaging techniques.

Difference Between Swept Source OCT and Spectral Domain OCT

Swept Source OCT

Swept-Source OCT which is also known as Fourier-Domain OCT is utilized to diagnose defects in ocular tissue and nervous tissues. It uses the principle of SLD’s and a tunable laser as its light source. The laser emits light across a broad range of wavelengths which allows for faster imaging and deeper penetration into ocular tissues. 

What Makes It Different From Spectral Domain OCT 

While serving the same aim and purpose as swept domain OCT, swept source OCT marks a difference in several aspects of technology and application. Let’s have a wider view of it.

Technological Differences

1. Increased Imaging Speed: SS-OCT offers higher scan speeds compared to SD-OCT. It enables rapid acquisition of three-dimensional images of the ocular tissues that can’t be simply noticed by microscopes. 

2. Deeper Penetration: The longer wavelength light used in SS-OCT allows for deeper penetration into ocular tissues. It makes imaging structures easy and suitable for exceptionally thin layers such as the choroid and sclera.

3. Reduced Motion Artifacts: SS-OCT is less susceptible to motion artefacts caused by patient movement during image acquisition due to its faster scan speed.


1. Choroidal Imaging: SS-OCT’s longer wavelength light allows for deeper penetration into ocular tissues. It is particularly useful for imaging the choroid. Swept source OCT provides detailed visualization of choroidal thickness and vascularity. That’s why it is useful for aiding in the diagnosis and management of conditions such as choroidal neovascularization (CNV) and central serous chorioretinopathy (CSCR).

2. Anterior Segment Imaging: SS-OCT can capture high-resolution images of the anterior segment structures. It includes the cornea, iris, and anterior chamber angle. It is valuable for assessing corneal thickness, angle morphology, and the presence of anterior segment pathologies. This aspect is very important in the diagnosis of glaucoma. 

Spectral Domain OCT

Spectral domain OCT is also one of the most advanced technologies that are tremendously useful in the field of ophthalmology. Coming from the same competitive background, SD-OCT provides a different technology and application in comparison to spectral source OCT. Read the following differentiations for a transparent observation.

What Makes SD-OCT Different From SS-OCT

SD-OCT implements a broadband light spectrum and spectrometer to trace the interference which is opposite to SS-OCT. Therefore, it differs from spectral source OCT in various aspects such as…

Technological Aspects

High Resolution: SD-OCT provides high-resolution cross-sectional images of the retina. It allows for detailed visualization of retinal layers and pathologies.

Real-Time Imaging: SD-OCT systems offer real-time imaging capabilities. Therefore, provides opportunities for dynamic imaging techniques such as angiography and motion tracking.

Wide Clinical Utility: SD-OCT is used for various applications in ophthalmology. The famous applications include the diagnosis and monitoring of retinal diseases such as macular degeneration, diabetic retinopathy, and glaucoma.


Retinal Imaging: SD-OCT is widely used for high-resolution imaging of the retinal layers. Using it, doctors can opt for a detailed assessment of retinal thickness and morphology. It is essential for diagnosing and monitoring retinal diseases such as macular degeneration, diabetic retinopathy, and retinal vascular disorders.

Angiography: SD-OCT has potential angiography capabilities such as OCT angiography (OCTA) and enables non-invasive visualization of retinal and choroidal blood flow. OCTA provides valuable information about retinal vascular perfusion in diseases like diabetic retinopathy and macular telangiectasia.

Summarizing The Difference:

Factors Swept Source OCT Spectral Domain OCT
Wavelength Range >1050 nm<1050 nm
Depth Of Penetration 5-6 nm2-3 nm
Resolution 10-20 micrometer 5-10 micrometer
Imaging Speed100000-400000 scans per second 100000-200000 scans per second 

Wrap Up

Wrapping it up, both swept source OCT and spectral domain OCT have significant benefits in the field of healthcare. However, the requirements always differ to diagnose and prevent different medical conditions for both technologies. Therefore, it will be difficult to say which one is better than the other as both technologies play a vital role in different segments.