Unlike standard OCT, en face OCT employs software to construct an image cube of the posterior pole. This produces a transverse image of the retina and choroid at any specified depth—essentially cutting through layers and providing an extensive overview of pathological structures in a single image. For glaucoma suspects, this means clinicians can better observe the structures where glaucoma is first evident. Researchers are now showing that the use of en face images seems to influence clinicians’ treatment choices.
The research looked at 30 patients who were examined in three ways: a standard presentation of circumpapillary retinal nerve fiber layer (RNFL) scans, 24-2 perimetry results and en face imaging, including RNFL depth scans, custom segmentation of the RNFL and a custom normalized en face reflectance probability map.
The researchers asked clinicians to review the images and assess whether glaucoma was likely present using a five-point scale (strongly disagree, disagree, neutral, agree, strongly agree) and to recommend a management plan (start treatment, return in three months, return in six months, recommended yearly OCT and 24-2, discharge as the patient is deemed to be low risk) for the first two presentations. After the en face presentation, the initial two questions were asked along with a third one on whether the en face image was helpful for each of the three formats.
The study shows that, when asked whether the participant illustrates glaucomatous optic neuropathy after viewing the second standard presentation, “agree” or “strongly agree” was selected 29% of the time. When given the third presentation with en face reflectance, clinicians changed their ranking 59% of the time (46% toward likely to have glaucoma and 13% toward unlikely to have glaucoma). This shows the addition of en face imaging seems to moderately influence clinical decision making in the direction toward selecting “agree” on whether the subject had glaucomatous optic neuropathy and to start treatment.
Clinicians may be more responsive to data from imaging when there is a probability or a value provided rather than strictly visualizing potential defects as in the scroll-through scan, the researchers explained in their paper. By comparison, minimal changes were seen when comparing the first standard setting with the second.
|King B, Swanson W, Klemencic S, et al. Assessing the impact of en face retinal nerve fiber layer imaging on clinical decision making for glaucoma suspects. Optom Vis Sci. 2020;97(2):54-61.|