Do peripheral scotomas (areas of partial vision loss) show up on Optical Coherence Tomography (OCT) scans?

Detection of Peripheral Scotomas on OCT

Peripheral scotomas are generally not well visualized on standard OCT imaging, as conventional OCT is primarily designed to capture the posterior pole and has limited ability to image the peripheral retina.

Limitations of Standard OCT for Peripheral Scotomas

• Standard OCT has a limited field of view, typically focused on the central macula (6×6 mm area) 1
• Conventional OCT cannot reliably detect peripheral retinal pathology due to its limited scan range 2
• Peripheral scotomas may be missed entirely on standard OCT examinations, requiring alternative or specialized imaging techniques 3

Alternative Imaging Methods for Peripheral Scotomas

Widefield Imaging

• Widefield imaging technologies allow visualization of larger areas of the retina (>100° field of view) compared to conventional imaging modalities 1
• Wide-field OCT devices (such as OCT2) can image mid and far peripheral retinal pathologies that standard OCT cannot capture 2
• In one study, only 37% of lesions in the far periphery could be imaged by standard OCT, while specialized wide-field OCT could detect significantly more 2

Microperimetry

• Fundus-related macular microperimetry is more accurate for detecting both fixation patterns and scotomas 1
• Microperimetry uses eye-tracking technology to ensure stimuli are presented to the correct retinal position, making it superior for patients with unstable or nonfoveal fixation 1
• This technology can accurately detect both fixation location and stability, which is crucial for proper scotoma mapping 3

OCT Angiography (OCT-A)

• OCT-A can detect perfusion loss in the outer retinal layer that may correspond to scotomas, even when fluorescein angiography appears normal 4
• OCT-A allows depth-resolved, noninvasive blood flow detection based on motion contrast 1
• It may reveal vascular networks associated with scotomas that are not readily detected on conventional imaging 1

Clinical Considerations

• Peripheral scotomas may actually be central scotomas that appear peripheral due to eccentric fixation in patients with macular disease 3
• When a patient has eccentric fixation, the scotoma location may be mapped in the wrong location on standard visual field testing 1
• Special techniques are required for intraoperative OCT of the peripheral retina, such as using a Goldmann style mirrored contact lens in conjunction with microscope-integrated OCT 5

Practical Approach to Peripheral Scotoma Assessment

1. Begin with standard OCT to rule out macular pathology
2. If peripheral scotoma is suspected but not visualized on standard OCT:
   • Consider wide-field imaging technologies
   • Employ microperimetry for accurate scotoma mapping
   • Use OCT-A to detect possible vascular abnormalities
3. For very peripheral lesions, specialized techniques like OCT with Goldmann lens may be necessary

Pitfalls to Avoid

• Do not assume a paracentral scotoma is truly paracentral; it may be a central scotoma displaced by eccentric fixation 1
• Automated perimetry may be inaccurate in patients with unstable or nonfoveal fixation 1
• Patients often do not perceive their scotomas as black patches; they are usually invisible to the patient 6
• Relying solely on standard OCT may miss peripheral pathology that requires specialized imaging techniques 2