The interplay between cardiac disease and the eye

The connection between the two organs has only begun to be recognized in the fairly recent past. This recognition puts ophthalmologists and optometrists in a position to recognize many serious diseases, not the least of which focuses on the heart. In some cases, life-threatening and life-altering disorders can even be suspected before these diseases manifest systemically.

Josef Huemer, MD, and colleagues shared their insights from a large international study that looked at atrial fibrillation and changes in the retina.¹Huemer, the study’s lead author, is affiliated with NIHR Moorfields Biomedical Research Centre, the Institute of Ophthalmology, University College London, both in London, and the Department of Ophthalmology and Optometry, Kepler University Hospital, Linz, Austria.

Huemer and colleagues also pointed out how readily available imaging can be a great boon to patients and aid eye care clinicians in identifying alterations in the retina using macular optical coherence tomography (OCT) and color retinal photography. The information about atrial fibrillation is generally obtained from electrocardiograms. However, they noted, diagnosing atrial fibrillation can be tricky because it occurs sporadically on an electrocardiogram (ECG).

In their study of data from two databases, they found that atrial fibrillation was associated with significantly smaller retinal venular caliber and thinner macular retinal nerve fiber layer, ganglion cell-inner plexiform layer, inner nuclear layer (INL), photoreceptor layer, and thinner macular ganglion cell inner plexiform layer (mGCIPL). After adjusting for sociodemographic, clinical and lifestyle factors, each standard deviation decrease in the mGCIPL thickness was associated with a significant 27% increased hazard of AF, they reported.

In this Q&A, Huemer offered some guidance to eye care clinicians on interpreting scans and clinical actions.

Ophthalmology Times: Regarding physician awareness, how aware are ophthalmologists and optometrists that atrial fibrillation may leave signs in the retina? Based on your findings, what should they understand about this connection?

Josef Huemer, MD: Most ophthalmologists and optometrists are much aware of the signs of cardiovascular diseases and their retinal manifestations. They frequently observe hemorrhages, cotton wool spots, and other well-established signs of systemic cardiovascular disease. However, atrial fibrillation does not present with such signs; the characteristic signs are subtle and not disease specific. Therefore, it is important to highlight to the community that, if confirmed by further research, the retina may be of help to identify patients that may benefit from long-term cardiac monitoring.

OT: Interpreting scans: The mGCIPL and macular INL (mINL) findings were based on comparisons across large patient groups. Can clinicians apply them when viewing an individual patient’s OCT scan today, and how might they distinguish atrial fibrillation-associated thinning from thinning caused by glaucoma, diabetes, or other retinal or neurodegenerative conditions?

Huemer: This is an important message. At the moment these signs cannot and should not be used for individual level prediction. It is worth it to keep these findings in the back of the mind, especially in patients who have had strokes with no obvious underlying pathology, to look for changes and to keep an open mind about referring them to a cardiologist asking for long-term cardiac monitoring, which in most cases is non-invasive, but at the moment we are not able to use these signs to influence treatment decisions for individuals.

OT: Regarding clinical action, given that the study did not establish specific diagnostic criteria, what should an eye care provider do if they suspect that a patient may have undiagnosed atrial fibrillation or an elevated risk of developing atrial fibrillation? When would you recommend referral to primary care or cardiology, and what information should be shared?

Huemer: The patient’s history is highly relevant. Scans and images alone only tell you so much, but in the greater context of a patient’s recent history, these scans may be useful to direct patients to the right test. Atrial fibrillation is hard to detect, many patients are not aware that they have an irregular heartbeat, and a large proportion of patients with atrial fibrillation are not receiving appropriate treatment. This is why further research is essential to see whether OCT scans and color fundus photographs can add to early diagnosis and improve patient outcomes.

OT: Regarding the mechanism and next steps to be taken, you described the thinner mINL as a new finding. What might explain it, and does it suggest that retinal changes are a result of atrial fibrillation, a marker of shared underlying vascular disease, or both? What would multimodal imaging studies and outcomes research need to show before retinal imaging could be used routinely for early detection or risk stratification of atrial fibrillation?

Huemer: The INL is highly susceptible to ischemia based on its anatomic connections to the deep and intermediate capillary plexus of the retina and the high oxygen demand of the photoreceptors especially in the area of the macula. Previous work has shown the links between focal ischemia of the INL and cardiovascular disease, and a lot of research focuses on imaging biomarkers in this context. The next steps include a validation of these findings in the context of cardiovascular imaging and to see if these retinal biomarkers actually improve the individual risk prediction in comparison to existing methods.

Reference
1. Huemer J, Stuart KV, Zhou Y, et al. Atrial fibrillation and retinal imaging-based oculomics: a cross-sectional and longitudinal analysis of two large cohorts. PLOS Digit Health. 2026;5:e0001661. doi:10.1371/journal.pdig.0001661