On May 16, 2024, the field of ophthalmic imaging achieved a major milestone when the first home optical coherence tomography (OCT) device received marketing authorization from the US Food and Drug Administration (FDA). The inventions of all major imaging modalities, from the light microscope to magnetic resonance imaging, have resulted in significantly different protocols for management of specific diseases. The approval of home OCT will similarly impact the management paradigm for neovascular (“wet”) age-related macular degeneration (nAMD).

Home OCT and the Fourth Dimension

The idea of using home-based standard diagnostic tools is not new. The advent and wider adoption of continuous glucose monitors and wearable electrocardiogram (ECG) patches have paved the way for bringing in-office diagnostics to a patient’s home. Home-based diagnostics allow for a lower burden on patients and physicians, more granular data, and better disease management for acute conditions.

Home OCT enables patients to acquire OCT images in the convenience of their home. OCT images are automatically uploaded to the cloud, where an artificial intelligence (AI)–based algorithm analyzes the images for a key biomarker related to nAMD. The biomarker in this case is retinal hyporeflective spaces (HRS). These abnormal areas can often indicate the presence of fluid in the retina. The algorithm estimates the total volume of these spaces and represents it as Total Retinal hypOreflective (TRO) volume, represented in volume units (VU). The TRO volumes are plotted as a function of time and can be used to represent disease activity or treatment response (Figure 1). 

OCT became a mainstay for nAMD management because it clearly demonstrates the response of therapeutics by showing the disappearance of fluid in subsequent follow-up visits. Being able to see the third dimension — meaning the cross-section of the retina across the macula — that OCT provided was critical to visualize fluid. Home OCT promises to incorporate the fourth dimension, time, by providing high temporal clarity to disease dynamics and treatment response. These insights promise to optimize the management of nAMD through different disease stages.  

Early Stages of Wet AMD Management

Management immediately after diagnosis of nAMD is critical for good long-term outcomes. The DRCR Retina Network’s Protocol AK studied treatment-naïve patients with home OCT.¹ The study demonstrated significant heterogeneity in disease dynamics and treatment response, as shown by variation in the trajectory of HRS, or retinal fluid. The trajectories elucidate the response to treatment far more promptly and clearly than the monthly data capture currently used.

Many patients are currently managed via insurance-mandated step therapy. This typically involves using an off-label, less expensive drug (bevacizumab) for the first 1 to 3 treatments, followed by more expensive on-label therapies if needed. While cost effectiveness should be a goal of treatment protocols, such rigid paradigms completely ignore the heterogeneity among patients and their individual clinical needs, which could potentially result in suboptimal outcomes for individual patients. The challenge of identifying the optimal therapy for the patient early will only become more complex as newer therapies for nAMD are approved. 

Home OCT provides a fast and detailed view of treatment response through TRO volume trajectories. This information can help physicians decide on the optimal therapy for patients quickly and with much more certainty. The treatment frequency for the patients can also be optimized in these early stages, depending on the disease severity.

The Extension Phase 

The next phase in management of nAMD is to attempt to extend the patients to a longer treatment interval to reduce patient burden. This is currently done by extending the patients in steps of 1 to 2 weeks. Patients are usually extended until fluid recurrence is seen on OCT during an office visit or visual symptoms arise, and then the period is dialed back. This is effectively a coarse attempt to find a natural interval of fluid recurrence for the patient, if one exists, when the patient should ideally be treated before a clinically significant recurrence occurs.

Home OCT can achieve the goals of treat and extend (T&E) much more efficiently. Patients can be extended to the suitable interval without multiple steps of 1 to 2 week increments, but rather in a single step using near-daily imaging data. This was demonstrated in a case published by Holekamp et al in which a patient was extended to an 8-week interval using home OCT in a single step while maintaining excellent visual acuity.² 

Home OCT can provide a recurrence period with a very high temporal resolution so the patient can be treated prior to the next fluid recurrence, achieving the end goal of T&E-type management. In addition, home OCT provides a critical safety net as fluid recurrence periods may not be exactly periodic and, in the case of an early recurrence, a patient can be immediately treated to reduce the fluid exposure. Home OCT can also serve as a safety net if the practitioner decides to re-challenge the treatment interval in T&E-type management.

The Maintenance Phase

Once patients have achieved close to their maximum extension, they are managed at a fixed interval. Depending on the patient and provider preferences, some patients are treated at a periodic interval while others are managed on a pro re nata (PRN) basis. Home OCT can be an important tool in reducing burden on these patients, by using home OCT as a safety net during these long extensions. There is an example of managing a patient on long extension in the study cited above. The patient was monitored using home OCT and only treated on fluid recurrence. This patient required only a single treatment in a 6-month period while maintaining good visual acuity.² 

We expect this type of management to be commonplace when using long-acting agents like tyrosine kinase inhibitors (TKIs) or gene therapies. Patients on these long extension treatments can be monitored using home OCT as a safety net and brought in for rescue treatments if disease recurrence is observed. It should also be noted that, as retinal physicians move toward longer extension, the protection of the fellow eye with intermediate dry AMD becomes critical. Home OCT becomes an important tool for protecting that fellow eye, which can often be the patient’s better seeing eye. 

Potential to Stop Therapy

A subset of nAMD patients reach a point where disease recurrence is not seen for an extended period. There is a potential to stop therapy for such patients. However, it is currently not possible to predict if and when a group of seemingly stable patients will manifest the reactivation of disease.³ Home OCT can be used to monitor these patients for extended periods, significantly reducing the clinic visit burden on patients but giving them a much-needed safety net in case of vision-threatening reactivation of the disease. Such efficient digital workflows can help retina specialists manage more patients. Further studies are required to understand the optimal management of patients once they reach this stage in their AMD journey. Home OCT will likely be critical in both understanding and management of this stage.

Summary

Home OCT has a potential role to play in the different stages of nAMD management. We expect home OCT to be one of the many AI-assisted digital solutions that will be used in our field. This is great news for both retina specialists and our patients. However, only with deep clinical insights and meticulous implementation can a technological innovation translate into better health outcomes and enhanced patient experience. We expect this to be just the start of a journey for clinicians to come up with novel paradigms to use this technology to benefit their patients. RP

Anat Loewenstein, MD, MHA, is the head of retina and vice president of ambulatory services at Tel Aviv Medical Center and the Sidney Fox Chair of Ophthalmology at Tel Aviv University, Israel. She reports consultancy to Bayer, Novartis, Allergan, Roche, Beyeonics, and Notal Vision. Dr. Lowenstein can be reached at anatl@tlvmc.gov.il.

Mathew W. MacCumber, MD, PhD, is a professor and research director in the department of ophthalmology at Rush University Medical Center in Chicago, and in private practice at Illinois Retina Associates in Chicago. He reports no relevant disclosures.

References

1. Blinder KJ, Calhoun C, Maguire MG, et al. Home OCT imaging for newly diagnosed neovascular age-related macular degeneration: a feasibility study. Ophthalmol Retina. 2024;8(4):376-387. doi:10.1016/j.oret.2023.10.012

2. Holekamp NM, de Beus AM, Clark WL, Heier JS. Prospective trial of home optical coherence tomography–guided management of treatment-experienced neovascular age-related macular degeneration patients. Retina. 2024;44(10):1714-1731. doi:10.1097/IAE.0000000000004167

3. Aslanis S, Amrén U, Lindberg C, Epstein D. Recurrent neovascular age-related macular degeneration after discontinuation of vascular endothelial growth factor inhibitors managed in a treat-and-extend regimen. Ophthalmol Retina. 2022;6(1):15-20. doi:10.1016/j.oret.2021.03.010