An evidence‐based approach to the routine use of optical coherence tomography

Abstract

Optical coherence tomography is an imaging technology that has revolutionised the detection, assessment and management of ocular disease. It is now a mainstream technology in clinical practice and is performed by non‐specialised personnel in some settings. This article provides a clinical perspective on the implications of that movement and describes best practice using multimodal imaging and an evidence‐based approach. Practical, illustrative guides on the interpretation of optical coherence tomography are provided for three major diseases of the ocular fundus, in which optical coherence tomography is often crucial to management: age‐related macular degeneration, diabetic retinopathy and glaucoma. Topics discussed include: cross‐sectional and longitudinal signs in ocular disease, so‐called ‘red‐green’ disease whereby clinicians rely on machine/statistical comparisons for diagnosis in managing treatment‐naïve patients, and the utility of optical coherence tomography angiography and machine learning.

Case Series: Discordance Between Visible Retinal Nerve Fiber Layer Defects and Spectral Domain Optical Coherence Tomographic Analysis in Patients with Glaucoma

“…5 Rao and associates conclude increased incidence of false negative classification for preperimetric RNFL defects, small RNFL defects (likely due to averaging the entire sector), and superior quadrant RNFL defects. 6,7 When interpreting the significance of Sector, Quadrant, and Clock Hour displays, or any other global sector analysis, it must be noted that substantial amounts of anatomic area are being averaged together to give an overall value. When this happens, a small RNFL defect may be present, but averaging within the area may result in an overall value that falls within the device's normative database.…”

“…10 Another potential contributor to a false negative assessment is the inadequate biometric database for individuals with demographics that are not well-represented including refractive error, sex, age, underlying ocular diseases, and ethnicity. [6][7][8][9][10] In cases of high myopia the RNFL analysis can be affected by the presence of a staphyloma, creating a false determination of overall structural loss. As well, normative databases, scanning protocols, segmentation, and thickness calculation algorithms vary among different manufacturer platforms.…”

In Vivo FF-SS-OCT Optical Imaging of Physiological Responses to Photostimulation of Human Photoreceptor Cells

“…It obtains detailed cross-sectional and three-dimensional images that visualize anatomical structures and their pathological changes ( Fig. 8.1) and is now indispensable for diagnosing a manifold of clinically important diseases [15][16][17]. OCT is based on interference [18] and detects not only the intensity of scattered light with an axial resolution of a few micrometers, but also optical path length changes, which are calculated from the phase of the interference pattern that generates the OCT signal ( Fig.…”

Optical coherence tomography: seeing the unseen

“…The robust quantitative measures that OCT provides of the optic nerve head neuro‐retinal rim in glaucoma have now superseded the more traditional assessment of retinal nerve fibre layer thickness, and Fortune, in his review of this topic, highlights the evidence supporting their clinical adoption. There are still key limitations with using OCT imaging in glaucoma, such as the so‐called ‘red‐green disease’, where the likelihood of false positives (red disease) or false negatives (green disease) may be increased relative to traditional testing, as the indication of possible structural loss in glaucoma is contingent upon the underlying OCT normative database; Ly et al discuss these factors in their review.…”

“…In addition to demonstrating how OCT can play an important role in the management of glaucoma, Ly et al provide practical, illustrative guides on the interpretation of OCT for AMD and diabetic retinopathy. They also outline how OCT has virtually become indispensable in clinical practice, due to its high sensitivity for diseases, such as neovascular AMD and diabetic macular oedema.…”