OCT (Optical Coherence Tomography)

Optical coherence tomography (OCT) is a non-invasive imaging technology that uses light waves to create detailed cross-sectional images of the retina and optic nerve. Think of it like an ultrasound, but using light instead of sound.

Why It's Done

• Evaluate optic nerve damage in optic neuritis
• Measure retinal nerve fiber layer (RNFL) thickness
• Detect papilledema and optic disc swelling
• Monitor IIH and glaucoma
• Assess macula for retinal conditions

What to Expect

Before the Test

• Pupils may or may not be dilated
• No special preparation needed

During the Test

• Sit with chin on rest
• Look at target light
• Machine scans your eye with safe light beam
• You'll see a red line scanning across
• Takes 5-10 minutes total

After the Test

• No recovery time needed
• Results available immediately
• Can drive home (unless dilated)

What It Shows

Retinal Nerve Fiber Layer (RNFL)

• Thickness around optic disc
• Thinning suggests nerve damage (optic atrophy)
• Thickening suggests swelling

Ganglion Cell Analysis

• Measures inner retinal layers
• Early damage may show here first

Optic Nerve Head

• Disc shape and cupping
• Swelling or atrophy

Macula

• Central retinal structure
• Detects macular problems

Comparing Over Time

OCT is excellent for tracking changes:

• Compare scans at different visits
• Detect subtle progression
• Guide treatment decisions