Optical coherence tomography in the management of diabetic macular oedema

Diabetic macular oedema (DMO) is the major cause of visual impairment in people with diabetes. Optical coherence tomography (OCT) is now the most widely used modality to assess presence and severity of DMO. DMO is currently broadly classified based on the involvement to the central 1 mm of the macula into non-centre or centre involved DMO (CI-DMO) and DMO can occur with or without visual acuity (VA) loss. This classification forms the basis of management strategies of DMO. Despite years of research on quantitative and qualitative DMO related features assessed by OCT, these do not fully inform physicians of the prognosis and severity of DMO relative to visual function. Having said that, recent research on novel OCT biomarkers development and re-defined classification of DMO show better correlation with visual function and treatment response. This review summarises the current evidence of the association of OCT biomarkers in DMO management and its potential clinical importance in predicting VA and anatomical treatment response. The review also discusses some future directions in this field, such as the use of artificial intelligence to quantify and monitor OCT biomarkers and retinal fluid and identify phenotypes of DMO, and the need for standardisation and classification of OCT biomarkers to use in future clinical trials and clinical practice settings as prognostic markers and secondary treatment outcome measures in the management of DMO.

Clinically relevant factors associated with a binary outcome of diabetic macular ischaemia: an OCTA study

AIMS

We investigated the demographic, ocular, diabetes-related and systemic factors associated with a binary outcome of diabetic macular ischaemia (DMI) as assessed by optical coherence tomography angiography (OCTA) evaluation of non-perfusion at the level of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in a cohort of patients with diabetes mellitus (DM).

MATERIALS AND METHODS

617 patients with DM were recruited from July 2015 to December 2020 at the Chinese University of Hong Kong Eye Centre. Image quality assessment (gradable or ungradable for assessing DMI) and DMI evaluation (presence or absence of DMI) were assessed at the level of the SCP and DCP by OCTA.

RESULTS

1107 eyes from 593 subjects were included in the final analysis. 560 (50.59%) eyes had DMI at the level of SCP, and 647 (58.45%) eyes had DMI at the level of DCP. Among eyes without diabetic retinopathy (DR), DMI was observed in 19.40% and 24.13% of eyes at SCP and DCP, respectively. In the multivariable logistic regression models, older age, poorer visual acuity, thinner ganglion cell-inner plexiform layer thickness, worsened DR severity, higher haemoglobin A1c level, lower estimated glomerular filtration rate and higher low-density lipoprotein cholesterol level were associated with SCP-DMI. In addition to the aforementioned factors, presence of diabetic macular oedema and shorter axial length were associated with DCP-DMI.

CONCLUSION

We reported a series of associated factors of SCP-DMI and DCP-DMI. The binary outcome of DMI might promote a simplified OCTA-based DMI evaluation before subsequent quantitative analysis for assessing DMI extent and fulfil the urge for an updating diabetic retinal disease staging to be implemented with OCTA.

Case Report: Retinal Vasculitis in Two Adolescents After COVID-19 Vaccination

PURPOSE

To report two cases of bilateral retinal vasculitis in adolescents following COVID-19 vaccination.

STUDY DESIGN

Case report.

RESULTS

 We report the first two cases of retinal vasculitis in adolescents following COVID-19 vaccinations. Both patients received recent second-dose COVID-19 vaccinations (7 weeks and 4 weeks respectively), and presented with bilateral retinal vasculitis and vitritis. Investigations did not reveal other causes of retinal vasculitis. Both patients' retinal vasculitis settled with a short course of oral prednisolone.

CONCLUSION

Although rare, the temporal association between vaccination, bilateral eye involvement, and the absence of alternative infective or inflammatory causes, makes this a plausible etiology. mRNA vaccinations may cause an autoimmune reaction via host antigenic mimicry, and systemic vasculitis has previously been described. We believe that a short interval between COVID-19 vaccination doses might be a risk factor for the development of retinal vasculitis in adolescents, and clinicians should be aware to elicit vaccination history.

OCT-based biomarkers for predicting treatment response in eyes with centre-involved diabetic macular oedema treated with anti-VEGF injections: a real-life retina clinic-based study

BACKGROUND/AIMS

To determine whether a combination of baseline and change in spectral domain-optical coherence tomography (SD-OCT)-based biomarkers can predict visual outcomes in eyes with diabetic macular oedema (DMO) treated with antivascular endothelial growth factors (VEGF) injections.

METHODS

This is a retrospective cohort study conducted in Hong Kong, China. 196 eyes with centre-involving DMO, who received anti-VEGF injections between 1 January 2011 and 30 June 2018 were recruited. Medical records of the participants were retrieved retrospectively, visual acuity (VA) at baseline, 6, 12 and 24 months and SD-OCT before initiation and after completion of anti-VEGF treatment were obtained. The SD-OCT images were evaluated for the morphology of DMO, vitreomacular status, presence of disorganisation of retinal inner layers (DRIL), sizes of intraretinal cysts, visibility of external limiting membrane (ELM), ellipsoid zone (EZ) and cone outer segment tip (COST) and the presence of hyper-reflective foci in retina or the choroid.

RESULTS

The presence of baseline DRIL, hyper-reflective foci in retina and disruption of ELM/EZ and COST were associated with worse baseline and subsequent VA up to 24 months after treatment. Improvement in DRIL (p=0.048), ELM/EZ (p=0.001) and COST (p=0.002) disruption after treatment was associated with greater improvement in VA at 12 months. Eyes with cystoid macular oedema (p=0.003, OR=8.18) and serous retinal detachment (p=0.011, OR=4.84) morphology were more likely to achieve at least 20% reduction in central subfield thickness.

CONCLUSION AND RELEVANCE

Baseline SD-OCT biomarkers and their subsequent change predict VA and improvement in vision in eyes with DMO treated with anti-VEGF injections. We proposed an SD-OCT-based system that can be readily used in real-life eye clinics to improve decision making in the management of DMO.

Massive retinal infiltrates as the presenting sign of chronic myeloid leukemia: Clinical and imaging features of leukemic retinopathy

PURPOSE

To describe the clinical and optical coherence tomography (OCT) features of two cases with bilateral diffuse retinal infiltrates as the only presenting feature of chronic myeloid leukemia (CML) on initial diagnosis and upon relapse.

METHODS

We reported two patients with CML, one at initial diagnosis and one in remission who presented with bilateral subacute visual impairment. Fundal examination revealed bilateral symmetrical leukostatic appearance with increased vascular tortuosity, diffuse retinal infiltrates with size up to 6 disk diameters, retinal hemorrhages, and Roth's spots. OCT showed multiple intra-retinal hyper-reflective foci corresponding to intra-retinal hemorrhages, and outer retinal hyper-reflective foci in area corresponding to retinal infiltrate. The different retinal layers were relatively preserved and distinguishable.

RESULTS

White cell count (WCC) were elevated in both patients ranging from 544 to 810 × 10⁹/L. Bone marrow biopsy confirmed the diagnosis of CML in the patient without prior diagnosis and relapse of CML in another patient. Cytogenetic test detected Abelson murine leukemia (ABL) - breakpoint cluster region (BCR) fusion transcript in both cases. Both patients were started on oral imatinib, subsequently WCC returned to within normal values in both cases. Vision and OCT abnormalities improved and reduction in retinal hemorrhages and infiltrates were observed in follow up.

CONCLUSION

This report highlights the important role of ophthalmologists and detailed fundus examination in making a prompt diagnosis of leukemia in patients with visual complaints. Appropriate systemic investigation and hematologist referrals for prompt treatment of CML may improve survival rate and preserve vision.

Relationship of intercapillary area with visual acuity in diabetes mellitus: an optical coherence tomography angiography study

AIM

To examine the correlation of best-corrected visual acuity (BCVA) with intercapillary area (ICA) measured from optical coherence tomography angiography (OCT-A) in patients with diabetes, and to compare the strength of associations between BCVA with ICA and other OCT-A metrics.

METHODS

A cross-sectional study involved 447 eyes from 299 patients with diabetes. All participants underwent OCT-A with a swept-source OCT (Triton DRI-OCT, Topcon, Tokyo, Japan). An automated customised MATLAB programme was used to quantify ICA (the mean of the 10 largest areas including foveal avascular zone (FAZ) area (ICA10_FAZ) and excluding FAZ area (ICA10_excFAZ)) and other OCT-A metrics (FAZ area, FAZ circularity and vessel density) from the macular OCT-A images. BCVA was measured using Snellen chart for the patients and then converted to logarithm of the minimum angle of resolution (logMAR) VA. We further defined 'good VA' as Snellen >0.7 and 'poor VA' as Snellen ≤0.7 as a binary VA outcome for logistic regression analysis.

RESULTS

In univariate regression analysis, increased ICA10_FAZ and ICA10_excFAZ were significantly correlated with logMAR (p values <0.05). In multivariate regression analysis, only the association between ICA10_FAZ and logMAR persisted (β=0.103, p=0.024). In multivariable logistic regression analysis, increased ICA10_FAZ (OR=1.300, 95% CI 1.076 to 1.679, p=0.044) and FAZ circularity (OR=1.285, 95% CI 1.031 to 1.603, p=0.026) showed significant associations with poor VA.

CONCLUSIONS

Increased ICA measured from OCT-A, describing enlargement of capillary rarefaction or closure at macular area, is independently associated with BCVA, suggesting that ICA is a potential marker to quantify retinal microvascular abnormalities relating to vision among individuals with diabetes.

An examination of Quercus championi of Hong Kong

The leaves of Quercus championi yield hop-17(21)-en-3β-ol (Ia), hop-17(21)- en-3β-yl acetate (Ib), β-amyrenyl acetate, friedelin, and friedelan-3α-ol. Neither the hopenol nor its acetate have been obtained from plants before; nor has this acetate ever been obtained in a pure state before.