Posterior Optical Coherence Tomography (OCT)

Post Image

Posterior Optical Coherence Tomography (OCT)

What is Optical Coherence Tomography (OCT)?

Posterior OCT is an advanced imaging technique used to perform a high-resolution scan of the fundus structures, allowing detailed in vivo views of the retina's layers and, in the latest models, up to the choroid (the layer just beneath the retina). This technique is essential for diagnosing and monitoring various retinal and optic nerve conditions.

With technological advancements, OCT angiography now allows the visualization of blood circulation in the retina, providing even more detailed information about vascular health.

What Does Posterior OCT Involve?

Posterior OCT is a minimally invasive, painless imaging technique that requires no direct contact with the eye. It uses infrared light that reflects off the retina, producing a detailed 3D map of the ocular structures. The most recent models use Spectral Domain (SD) and Swept Source technologies for enhanced depth and faster image capture.

  • Spectral Domain (SD): Provides high-resolution images of retinal structures.
  • Swept Source Technology: The latest advancement, allowing better imaging of deeper retinal layers, including the choroid.

How is it Performed?

  1. Duration: The test is quick, taking around 5 minutes.
  2. Preparation: No special preparation is required, and pupil dilation is not necessary.
  3. Non-contact: The test involves no physical contact with the eye and is completely painless.

In What Cases Is It Used?

Posterior OCT is crucial for detecting subtle morphological changes in the eye, making it indispensable in diagnosing and monitoring a range of retinal and optic nerve diseases. Common conditions assessed with posterior OCT include:

  1. Age-Related Macular Degeneration (AMD): Monitoring retinal changes in macular degeneration.
  2. Macular Oedema: Often seen in diabetic retinopathy or retinal vascular occlusions.
  3. Macular Epiretinal Membrane: Diagnosis and monitoring.
  4. Glaucoma: Detailed images of the nerve fibre layer in the retina and the optic nerve head, assisting in glaucoma diagnosis and management.

Associated Pathologies

  1. Macular Epiretinal Membrane (MEM): A condition that causes distortion in the macula, often monitored with OCT.
  2. High Myopia: Can lead to changes in the retina that OCT can detect.
  3. Retinal Vein Occlusions: OCT helps in diagnosing and monitoring the effects of retinal vein blockages.
  4. Diabetic Retinopathy: OCT is crucial in detecting diabetic retinal changes and monitoring progression.
  5. Retinitis Pigmentosa: OCT can help assess retinal degeneration.
  6. Uveitis: OCT aids in assessing inflammation within the eye.
  7. Macular Hole: OCT helps evaluate the macula in patients with holes in the retinal layers.
  8. Retinal Detachment: Post-surgery monitoring and early detection of complications.
  9. Stargardt Disease: OCT helps in the diagnosis of this inherited retinal disorder.

Conclusion

Posterior OCT is a vital tool in modern ophthalmology, providing high-resolution, non-invasive imaging that helps in the early detection and ongoing monitoring of many retinal and optic nerve conditions. With the introduction of advanced technologies like Swept Source OCT, this technique continues to enhance our ability to manage and treat serious eye diseases effectively.