EURETINA 2026: OCT biomarkers that predict, preempt and pinpoint retinal disease

Three studies presented at the 26th EURETINA Congress, taking place at the VIECON – Vienna Congress & Convention Center from 1 to 4 October, make the case that optical coherence tomography (OCT) and OCT angiography (OCTA) have a role to play at every stage of retinal disease. One tracks how structural and vascular biomarkers shift after a patient starts treatment for neovascular age-related macular degeneration (nAMD). Another finds that diabetic retinopathy (DR) leaves a detectable trace on OCT and on selective visual field testing before macular oedema ever develops. A third uses multimodal imaging, including OCTA, to work through a single case of ocular toxoplasmosis.

Taken together, the three point to a common thread: Imaging biomarkers that can predict how a patient will respond, preempt disease before it becomes clinically obvious or pinpoint a diagnosis that might otherwise be missed.

Predicting response: Biomarkers track recovery from wet AMD

A prospective case series from a tertiary retina referral centre in São Paulo, Brazil, followed 21 eyes of 21 treatment-naïve patients with nAMD through a loading phase of three monthly intravitreal aflibercept injections.¹ Patients were assessed at baseline and again one month after the loading phase, at the four-month visit, using swept-source OCT (SS-OCT) and swept-source OCTA (SS-OCTA) alongside best-corrected visual acuity (BCVA).

Every biomarker measured improved after treatment except intraocular pressure. Mean BCVA improved from 1.11 ± 0.47 to 0.56 ± 0.20 logMAR (P < .001), while central macular thickness (CMT) and central choroidal thickness (CCT) on SS-OCT, along with macular neovascularisation area, superficial-plexus avascular area and deep-plexus avascular area on SS-OCTA, were all significantly lower post-treatment.

The correlations between baseline and outcome measures were, in the authors' view, the more striking finding. Baseline CMT was highly predictive of how much CMT would fall with treatment (r=−0.95; P < .001) and moderately correlated with posttreatment CMT (r = 0.53; P = 0.013). Baseline CCT correlated strongly with posttreatment CCT (r = 0.87; P = 0.002), and baseline macular neovascularisation area was moderately negatively correlated with posttreatment CCT (r = −0.51; P = .019). BCVA correlated significantly with CMT at both time points, and further associations linked the deep-plexus avascular area to baseline CMT and CMT reduction, and changes in the superficial-plexus avascular area to CCT.

The authors, led by Marcussi Rezende, concluded that baseline SS-OCT and SS-OCTA biomarkers do more than reflect how advanced a patient's disease is at presentation: They are closely tied to the size and direction of the anatomical and vascular remodelling that follows treatment. They describe the findings as novel and not previously reported in the literature, and argue they support using integrated multimodal biomarker assessment to stratify prognosis and individualize management in treatment-naïve nAMD.

Preempting progression: OCT and selective perimetry catch DR before oedema

A prospective single-centre study from a tertiary university hospital in Türkiye asked how early, structurally and functionally, diabetic retinopathy shows itself before macular oedema develops.² Ezgi Barbarus and Sema Dundar examined 148 eyes of 100 patients with DR but no macular oedema, using Early Treatment Diabetic Retinopathy Study-based fundus photography, spectral-domain OCT with choroidal thickness measurement, and three forms of visual field testing: standard automated perimetry (SAP), short-wavelength automated perimetry (SWAP) and frequency-doubling technology (FDT). Eyes were stratified by DR severity (mild versus moderate-or-worse) and by the presence of disorganisation of the retinal inner layers (DRIL), with imaging and functional outcomes independently assessed by two masked graders.

Eyes with moderate-or-worse DR had a significantly higher prevalence of DRIL (P = 0.042) and significantly thinner choroids (p=0.011) than eyes with mild disease. Paracentral acute middle maculopathy turned up in 5.4% of eyes overall, and eyes with DRIL had significantly more hyperreflective retinal foci than those without (P = .043).

The functional testing produced a more selective picture. SWAP picked up significant reductions in foveal threshold (P = .025) and a significant increase in pattern standard deviation (P = .010) across DR severity groups, while SAP and FDT showed no significant differences between groups. Visual field outcomes did not differ significantly between eyes with and without DRIL.

The authors concluded that structural OCT biomarkers, choroidal thinning and selective short-wavelength sensitivity loss are all detectable in DR before macular oedema appears, supporting the idea that neurovascular involvement in DR begins earlier than oedema-based staging suggests. They note that SWAP appears to be picking up functional impairment that conventional perimetry misses, and argue that recognizing these early changes could improve risk stratification and prognostic assessment in DR.

Pinpointing diagnosis: Multimodal imaging works through a case of ocular toxoplasmosis

The third study, from Hospital de Olhos Santa Luzia in Brazil, is a single case report rather than a cohort study, but it makes a related point from the diagnostic end of the disease course.³ Marilia Oliveira and colleagues followed one patient with toxoplasmic chorioretinitis through the acute, subacute and late phases of disease, using OCTA, structural OCT and retinography to characterize the lesion at each stage, with particular attention to what OCTA showed before and after treatment.

The presenting features were classic for the condition: a unilateral focal area of yellowish-white necrotic retina with indistinct margins adjacent to a pigmented scar, described in the literature as a “headlight in the fog” appearance. In this patient, a scarring lesion in one eye sat opposite an active lesion in the other, a pattern that helped point the clinical team toward the diagnosis.

On structural OCT, the active lesion showed mild-to-moderate vitritis, retinal oedema, focal choroidal thickening beneath the area of retinitis and a hyporeflective choroidal signal before treatment began. OCTA showed reduced flow signal that corresponded to those same structural changes in both the retina and the choroid.

The authors concluded that OCTA is an effective tool for investigating both retinal and choroidal involvement in active toxoplasmic chorioretinitis, and that the case supports the idea that the choroid, not only the retina, is substantially involved in the disease and should be assessed as a matter of course. They argue that non-invasive choroidal imaging with OCT and OCTA could help clinicians distinguish toxoplasmic chorioretinitis from other entities, gauge the true extent of the lesion beyond the retina and track it over follow-up, and they call for future studies to focus on separating retinal from choroidal involvement for prognostic purposes.

Three studies, one lens

Placed side by side, the three studies trace a single instrument's reach across the full arc of retinal disease. In nAMD, OCT and OCTA biomarkers measured before treatment starts help predict how much a patient will improve. In DR, the same imaging modalities, paired with selective visual field testing, can flag disease activity before macular oedema forces the issue. In ocular toxoplasmosis, multimodal imaging including OCTA helps confirm a diagnosis and map how far the disease reaches beneath the retina. None of the three studies claims to change practice on its own, but together they make a case that clinicians examining these images are, increasingly, being asked to look for signals that come before the disease that is normally the trigger for action.

References

1. Rezende M, Faria F, Beraldo D, Polido J, Belfort R, Cabral T. Correlation analysis of swept-source OCT and OCT angiography biomarkers in treatment-naïve patients with neovascular age-related macular degeneration treated with aflibercept: a prospective study. Presented at: 26th EURETINA Congress; October 1-4, 2026; Vienna Congress & Convention Center, Vienna, Austria.

2. Barbarus E, Dundar S. Early neurovascular disruption before macular edema in diabetic retinopathy: structural OCT biomarkers and selective short-wavelength sensitivity loss. Presented at: 26th EURETINA Congress; October 1-4, 2026; Vienna Congress & Convention Center, Vienna, Austria.

3. Oliveira M, Villarim P, Gantois M, Albuquerque P, Oliveira M. Toxoplasmic chorioretinitis: case report and emphasis on multimodal imaging including optical coherence tomography angiography and complementary exams. Presented at: 26th EURETINA Congress; October 1-4, 2026; Vienna Congress & Convention Center, Vienna, Austria.