Age-related macular degeneration (AMD) is a common eye condition affecting central vision, making tasks like reading or recognizing faces challenging. It is a leading cause of vision loss among older adults, though it typically does not lead to complete blindness as peripheral vision remains intact. Early detection and ongoing management are important for preserving sight and slowing disease progression. Optical Coherence Tomography (OCT) is a non-invasive imaging technology that has significantly improved AMD diagnosis and monitoring.
Understanding Optical Coherence Tomography
Optical Coherence Tomography (OCT) is a non-invasive imaging method used by eye care professionals to create cross-sectional images of the retina. Often described as an “optical ultrasound,” OCT uses light waves instead of sound waves to visualize the eye’s internal structures. It works by emitting a light beam into the eye and measuring the time delay and intensity of light reflected from different retinal layers. This creates high-resolution, three-dimensional images showing distinct retinal layers at a micron level of detail. OCT’s speed and precision provide a comprehensive view of the retina’s architecture, enabling detection of subtle tissue changes.
OCT’s Indispensable Role in Macular Degeneration
OCT is a key tool in diagnosing and managing both dry (atrophic) and wet (neovascular) forms of age-related macular degeneration. For dry AMD, OCT identifies and monitors drusen, small yellow protein deposits under the retina. Images also show geographic atrophy, a thinning of the retina and retinal pigment epithelium (RPE) in advanced dry AMD. OCT’s visualization of these features helps track disease progression and assess vision loss risk.
In wet AMD, OCT detects abnormal blood vessel growth, known as choroidal neovascularization (CNV), which can leak fluid and blood. The scan reveals signs like intraretinal fluid (fluid within retinal layers), subretinal fluid (fluid beneath the retina), and pigment epithelial detachments (PEDs), where the RPE separates from underlying layers. These OCT findings guide treatment decisions, especially for anti-VEGF injections, which reduce fluid leakage and inhibit vessel growth. OCT also monitors treatment effectiveness by tracking fluid resolution and CNV lesion stability.
The OCT Scan Experience and What the Images Reveal
An OCT scan is a simple experience. During the procedure, you sit in front of the OCT machine and rest your chin on a support. You focus on a target light while the device scans your eye without physical contact. The entire process is quick, typically taking 5 to 10 minutes. While pupil dilation with eye drops is often used for a better view, it is not always required.
Once complete, the OCT machine generates detailed, color-coded images providing a cross-sectional “map” of your retina. Eye care professionals examine these images to identify findings like drusen presence and size, retinal thinning (atrophy), or fluid pockets suggesting active wet AMD. They also assess retinal layer thickness and detect structural abnormalities. This information helps your doctor understand retinal health, diagnose conditions, and formulate a personalized management plan.