Long-term retinal dysfunction following COVID-19 infection: a one-year prospective observational study, 2026, Mou et al.

[SNT Gatchaman]

Long-term retinal dysfunction following COVID-19 infection: a one-year prospective observational study
Mou, Kefan; Gao, Yuzhu; Zhang, Yifan; Man, Shulei; Chen, Qing; Xu, Hanyue; Chen, Yi; Zhang, Ming

BACKGROUND
COVID-19, caused by SARS-CoV-2, may lead to long-term retinal changes. Visual symptoms and retinal alterations have been reported in Long COVID; however, the available evidence remains limited. Swept-source OCT (SS-OCT) and OCT angiography (SS-OCTA) enable non-invasive evaluation of retinal structure and microvasculature. This study aimed to assess retinal alterations before and one year after COVID-19 using SS-OCT and SS-OCTA in a longitudinal design.

METHODS
This prospective longitudinal study was conducted at West China Hospital, Sichuan University. All enrolled participants underwent SS-OCT and SS-OCTA before infection, and at 1 month, and 1 year after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Retinal structural and microvascular alterations were quantified using the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, including the thickness of peripheral retinal nerve fiber layer (pRNFL), ganglion cell inner plexiform layer (GCIPL), inner nuclear layer (INL) and outer retina, and the vessel density (VD) of superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP). The foveal avascular zone (FAZ) area was measured in the inner retinal layer.

RESULTS
A total of 44 eyes from 22 participants were analyzed (mean age: 30.59 ± 9.36 years; 17 females and 5 males). Significant reduction in thickness of pRNFL, GCIPL, and outer retina, increased thickness of INL, decreased VD of SVP, and increased VD of ICP and DCP were observed in participants one month after COVID-19 infection (All P < 0.05), which remained persistently altered one year after COVID-19 infection (All P < 0.05).

CONCLUSIONS
These findings indicate long-term retinal dysfunction following COVID-19 infection, highlighting the importance of ongoing ophthalmic monitoring. Non-invasive SS-OCT and SS-OCTA could offer valuable tools for detecting and managing retinal alterations associated with long COVID in the post-pandemic era.

Web | DOI | PDF | BMC Ophthalmology | Open Access

 

[Utsikt]

No control group, but the participants were healthy and ~20-40 year old adults so rapid changes might not be expected?

 

[SNT Gatchaman]

Some open access normative data across age ranges if we want to look further into this.

Normative Optical Coherence Tomography Angiography Metrics of Macular Vessel Density and Foveal Avascular Zone in Healthy Children (2025, Journal of Clinical Medicine)

Spoiler: Abstract

BACKGROUND
Optical coherence tomography angiography (OCTA) enables non-invasive, high-resolution visualization of the retinal microvasculature and is increasingly utilized in pediatric ophthalmology. However, its clinical application in children is limited by the absence of age-specific normative data.

METHODS
In this cross-sectional study, macular vessel density (VD) and foveal avascular zone (FAZ) area were assessed in 118 healthy Caucasian children aged 4 to 17 years. OCTA scans were obtained using the OCT Topcon Triton® device with 3 × 3 mm and 6 × 6 mm macular cubes. Vascular metrics from the superficial (SCP) and deep capillary plexuses (DCP) were analyzed in relation to demographic, refractive, biometric, and structural OCT parameters. Correlation and multivariate linear regression analyses were performed to evaluate associations.

RESULTS
Age-stratified reference percentiles for macular VD and FAZ area in SCP and DCP are presented for 118 children. Key associations included: (1) Increased macular thickness correlated with higher VD in the fovea and inner ring (SCP and DCP, all p < 0.05); (2) Thicker maculas were associated with smaller FAZ areas (SCP: r = −0.72, DCP: r = −0.58, both p < 0.001); (3) Older age was linked to reduced VD in the inner macular ring and smaller FAZ area (SCP and DCP, all p < 0.001); and (4) longer axial length correlated with lower central VD (SCP: r = −0.27, DCP: r = −0.37, both p < 0.05). No significant sex-based differences were observed.

CONCLUSIONS
This study provides normative OCTA data for macular VD and FAZ area in healthy Caucasian children and identifies key associations with ocular parameters. These findings support improved diagnostic accuracy and clinical decision-making in pediatric retinal evaluation.

OCTA biomarkers in adults aged 50 and above: a prospective and cross-sectional community-based study (2023, BMC Ophthalmology)

Spoiler: Abstract

BACKGROUND/AIMS
To assess the normative values and parameters of optical coherence tomography angiography (OCTA) influencing the best corrected visual acuity (BCVA) in adults aged 50 and above.

METHODS
This was a prospective cross-sectional study from an eye screening programme in Hong Kong for 4188 citizens aged 50 and above. Images were analysed using a validated quantification software calculating vessel density and capillary perfusion density (CPD), along with other OCTA parameters, such as the foveal avascular zone area (FAZ) and circularity. OCTA data was collected from May 2019 to December 2020, including a total of 4188 healthy eyes from 4188 subjects.

RESULTS
Mean superficial vessel density (MSVD) was 14.48 ± 3.60 mm− 1, while the mean capillary perfusion density (MCPD) was 0.41 ± 0.06. Multivariate analysis revealed ageing (β = 0.321, p < 0.001), being male (β=-0.089, p < 0.001), having a high body mass index (BMI) (β = 0.039, p = 0.006), high FAZ area and low FAZ circularity (β = 0.039 and − 0.034, p = 0.01 and 0.024 respectively), low MSVD in the outer ring (β=-0.513, p < 0.001), specifically in the nasal and temporal outer quadrants (β = -0.226 and − 0.259, p < 0.001 for both), and low MCPD in the outer superior quadrant (β= -0.123, p = 0.016) being independently associated with BCVA.

CONCLUSION
High FAZ area and low FAZ circularity, low MSVD in the outer ring, specifically the nasal and temporal outer quadrants, and low MCPD in the outer superior quadrant can be used as biomarkers in predicting a low visual acuity in adults aged 50 and above.

Normative data and correlation parameters for vessel density measured by 6 × 6-mm optical coherence tomography angiography in a large chinese urban healthy elderly population: date from the Beichen eye study (2024, BMC Ophthalmology)

Spoiler: Abstract

BACKGROUND
To establish a normative database for macular vessel density (VD) measured by optical coherence tomography angiography (OCTA) and explore the parameters related to the VD.

METHODS
An observational study in epidemiology. 5840 healthy elderly participants in Beichen district, Tianjin, China underwent detailed ophthalmic and systemic examinations. OCTA was performed in all subjects using a 6 × 6-mm line scan mode centered on the macula and the built-in software was used to quantify VD and stratify the retina.

RESULTS
One thousand four hundred sixty-one healthy elderly citizens (30.4% men) were included, with a median age of 60.0 years (8.0 years) and an age range of 50 to 87 years.VDs in the different plexuses: superficial capillary plexus (SCP) 43.9% (3.2%), deep capillary plexus (DCP) 44.3% (2.8%), outer capillary plexus (OCP) 21.9% (5.9%), choriocapillaris (CC) 52.1% (1.4%). 90% medical reference range of the VDs at different plexuses was reported. Age was correlated with the VDs of each capillary plexus. Sex was correlated with the VDs of DCP and OCP, and the VDs of DCP (p < 0.001) and OCP (p = 0.015) in women were higher than that in men. After age and sex adjustment, choroid average thickness was positively correlated with VDs of SCP (R = 0.067, p = 0.010) and DCP (R = 0.108, p < 0.001), ganglion cell layer (GCL) average thickness (R = 0.072, p = 0.006) was positively correlated with the VD of OCP, best-corrected visual acuity (BCVA) (R = 0.082, p = 0.002) was positively correlated with the VD of CC.

CONCLUSIONS
In this study, the normative VD database of the Chinese urban healthy elderly population measured by the OCTA was established, and parameters related to the VD of each capillary plexus were analyzed, providing new ideas for the future study of the relationship between macular VD and disease. Trial registration The Beichen Eye Study had been registered on the Chinese Clinical Trial Registry website (registry number: ChiCTR2000032280) on April 25, 2020.