Macular Thickness Maps Effective Tools in Remote Monitoring of eAMD

Recurrent exudation in patients with exudative age-related macular degeneration (eAMD) could be easily identified through macular thickness maps (MTMs), making them effective tools to monitor the condition remotely, according to a study published in the American Journal of Ophthalmology.

eAMD relies on early intervention to treat, as visual outcomes have been found to correlate with baseline visual acuity at the time of treatment. Anti-vascular endothelial growth factor (VEGF) drugs are used every 4 weeks to treat patients with eAMD. Post-treatment best corrected visual acuity has been associated with early treatment and treatment with anti-VEGF drugs, which makes monitoring macular fluid important. This study aimed to find “the best stragety for determining when re-treatment might be needed based on the recurrence of worsening of macular fluid” based on optical coherence tomography (OCT) imaging, including MTMs.

The study consisted of a retrospective review of images that were taken from December 2008 to February 2021 of patients who were diagnosed with eAMD and being treated with anti-VEGF therapy at the Bascom Palmer Eye Institute. Those who were treated for at least 1 eye were included in the study. All patients had a spectral domain OCT image taken at each visit, with MTMs calculated with the macular thickness analysis algorithm. There were 5 retinal specialists who performed a grading exercise with the OCT MTMs alone or OCT B-scans alone.

A total of 53 eyes from 1385 imaging sessions were analyzed for this study. When using a CIRRUS review station as the standard to compare with, graders gave the same clinical recommendation when using the MTMs alone compared with the CIRRUS review station in 88.79% (SD, 1.10%) of cases. MTMs also had the highest sensitivity and lowest false negative rate. Agreements with the CIRRUS review station were 87.08% (SD, 1.98%) when presented with the central B-scan and 85.89% (SD, 1.09%) when presented with a 5 B-scan dataset.

There was no level of agreement percentage that was higher than 86.06% when using graders, which implies that agreement on whether a patient needs an in-office assessment may not be reached consistently. The highest level of agreement was found when graders were given thickness maps alone. When graders had access to the entire OCT review all 5 graders agreed in 82.31% of cases, with 4 of 5 agreeing in 11.63% of cases, and 6.06% of cases having agreement in 3 of 5 cases.

MTMs had the highest level of agreement (90.05%; SD, 0.78%) when averaging the scores of the 5 graders and comparing it to majority agreement when using the entire OCT review station. However, this was not statistically different compared with the other methods of evaluating macular thickness.

There were some limitations to this study. Interpreting MTMs takes a learning curve, which could affect the way that the maps are read. The OCT images used were also ones that were gathered from clinical practice and were not from a prototype home OCT instrument.

“While it is not our intention for remote monitoring of eAMD to replace routine office assessments, our results suggest that remote monitoring with MTMS could serve as a valuable screening tool, particularly in high-risk nonexudative AMD cases,” the authors wrote.

Reference

Trivizki O, Varcheie M, Bello S, et al. Assessing change in exudative AMD with macular thickness maps as a surrogate strategy for remote patient monitoring. Am J Ophthalmol. Published online July 25, 2023. doi:10.1016/j.ajo.2023.07.014