FLORetina 2025: Enrico Borrelli on reframing retinal disease through the lens of choroidal health

Increasingly, the choroid is being recognized as more than a structural backdrop in retinal disease, as it is an active participant in pathogenesis and a potential therapeutic target. Enrico Borrelli, MD, a retina specialist in the Medical Retina and Imaging Unit at University Vita-Salute San Raffaele in Milan, Italy, spoke on this intersection of choroidal pathology with common and complex retinal disorders at the FLORetina 2025 Congress, the 13th International Congress on OCT and OCT Angiography (ICOOR), held from December 4-7, in Florence, Italy.

In an interview with the Eye Care Network, Borrelli summarized his thoughts on the topic by outlining the multifactorial contributions of choroidal dysfunction to conditions such as age-related macular degeneration, diabetic retinopathy, and myopic maculopathy. He also emphasized how reductions in choroidal perfusion, often driven by age, systemic disease, or local insult, compromise the metabolic support to the retinal pigment epithelium (RPE) and photoreceptors.

From systemic factors that influence choroidal thickness to the promise of collaborative innovation showcased at FLORetina, Borrelli’s perspective underscores the choroid’s growing relevance in personalized retinal care.

Editor's note: Transcript edited for clarity and length.

How does choroidal pathology intersect with multiple retinal diseases?

Enrico Borrelli, MD: The choroid is fundamental to retinal function, and its dysfunction contributes to numerous retinal disorders through several pathways. Age-related reductions in choroidal blood flow increase vulnerability to damage, although systemic or local conditions can impair choroidal integrity even earlier in life. Diseases such as diabetes or myopia can disrupt choroidal structure and perfusion, and because the choroid nourishes the RPE and photoreceptors, any compromise in this layer can trigger or exacerbate retinal pathology.

What imaging biomarkers are most reliable for assessing choroidal health?

Borrelli: Modern imaging has transformed choroidal assessment. Structural OCT allows evaluation of choroidal thickness, a key indicator since thinning often reflects impaired perfusion. Metrics such as the choroidal vascularity index—which quantifies stromal versus vascular components—offer additional insight, as shifts toward increased stroma may signal disease. OCT angiography further enables non-invasive assessment of choriocapillaris flow, with reduced perfusion frequently linked to retinal pathology.

Are there therapeutic strategies targeting the choroid directly?

Borrelli: Direct choroid-targeted therapies are not yet available, but the choroid is an increasingly important focus for emerging pharmacologic and device-based strategies. Many current research programs aim to enhance choroidal perfusion, suggesting that dedicated treatments are likely to appear in the near future.

How do systemic factors influence choroidal thickness and function?

Borrelli: Choroidal thickness reflects both ocular and systemic influences. Beyond axial length, factors such as hypertension are commonly associated with thinning, whereas systemic inflammatory activity—such as in active lupus—can lead to thickening. Cardiovascular conditions like coronary artery disease or carotid stenosis also tend to correlate with a thinner choroid.

What research gaps remain in understanding choroidal involvement in ocular disease?

Borrelli: Significant gaps remain in defining how complex, age-related changes in choroidal perfusion contribute to disease onset and progression, particularly in conditions like age-related macular degeneration. Clarifying these mechanisms is essential for developing targeted interventions.

How does your time at FLORetina shape or challenge your perspective on retinal innovation?

Borrelli: FLORetina is a highly respected international meeting that strengthens collaboration among clinicians, researchers, and industry. Its environment fosters exchange of ideas and accelerates innovation, offering a broader and clearer view of the future landscape of retinal disease management.