Comparison of Macular Thickness Measurements Using Swept-Source and Spectral-Domain Optical Coherence Tomography in Healthy and Diabetic Subjects

The Reinforced Treat-and-Extend Protocol for Exudative Age-Related Macular Degeneration: Retrospective Assessment of 24-Month Real-World Outcomes in France

INTRODUCTION

The aim of this work is to evaluate the real-world outcomes of the reinforced treat-and-extend (RTE) protocol for the treatment of exudative age-related macular degeneration with intravitreal injections of aflibercept or ranibizumab (anti-vascular endothelial growth factor therapies).

METHODS

This was a retrospective review of patients from two tertiary ophthalmology centers in France initiating the RTE protocol between February 2018 and June 2021. The primary outcome was change in best-corrected visual acuity (BCVA) after 24 months. Secondary outcomes were change in central retinal thickness (CRT), recurrence, and management-related factors (injection interval, number of injections/consultations). Outcomes were additionally evaluated after protocol changes (strict versus modified RTE protocol groups).

RESULTS

Sixty-eight patients (72 eyes) were included (68% females; mean age 82.2 ± 7.8 years). After 24 months, mean BCVA significantly improved (65.22 ± 14 vs. 71.96 ± 13 Early Treatment Diabetic Retinopathy Study letters; p < 0.001) and CRT significantly decreased (388.6 ± 104 vs. 278.8 ± 51 μM; p < 0.001) with 21% of eyes showing signs of exudation. Over the 24 months, a mean total of 14.9 ± 4.0 injections and 8.6 ± 1.4 consultations were performed. Mean 24-month injection interval was 7.9 ± 2.3 weeks. Initial and 24-month ophthalmic outcomes for eyes in the strict (47%) versus modified (53%) groups were not significantly different, but mean time interval to first recurrence of disease activity was significantly shorter for the modified group (7.3 ± 2.4 vs. 9.9 ± 2.5 weeks; p < 0.001). Patients in the strict RTE group received significantly less injections (13.9 ± 3.6 vs. 16.5 ± 3.9; p = 0.006) and mean 24-month injection interval was significantly longer (9.5 ± 2.7 vs. 6.5 ± 2.1 weeks; p < 0.001). Consultation number was similar (8.5 ± 1.9 vs. 8.8 ± 1.6; p = 0.93). Treatment with aflibercept versus ranibizumab did not influence ophthalmic or management outcomes.

CONCLUSIONS

The RTE protocol, even when modified, reduced consultations but improved ophthalmic outcomes. The RTE protocol could reduce hospital visits and overall burden while also encouraging better patient compliance. Video Abstract available for this article.

VIDEO ABSTRACT

Vincent Soler and François-Philippe Roubelat summarize the Reinforced Treat-and-Extend Protocol and main results (MP4 225022 KB).

Reduced macular thickness and vascular density in abnormal glucose metabolism patients: A meta-analysis of optical coherence tomography (OCT) and OCT angiography studies

BACKGROUND

Alterations in macular thickness and vascular density before clinically visible diabetic retinopathy (DR) remain inconclusive. This study aimed to determine whether retinal manifestations in abnormal glucose metabolism (AGM) patients differ from those in the healthy individuals.

METHODS

PubMed, Embase, and Web of Science were searched between 2000 and 2021. The eligibility criteria were AGM patients without DR. Primary and secondary outcomes measured by optical coherence tomography (OCT) and OCT angiography (OCTA) were analyzed and expressed as standardized mean differences (SMDs) with 95% confidence intervals (CIs). A random-effects model was used in the data synthesis. The potential publication bias for the variables was evaluated using Egger's test.

RESULTS

A total of 86 observational studies involving 13,773 participants and 15,416 eyes were included. OCT revealed that compared to healthy controls, the total macular thickness of AGM patients was thinner, including the thickness of fovea (-0.24, 95% CI [-0.39, -0.08]; P  = 0.002, I2  = 87.7%), all regions of parafovea (-0.32, 95% CI [-0.54, -0.11]; P  = 0.003; I2  = 71.7%) and the four quadrants of perifovea; the thickness of peripapillary retinal nerve fiber layer (pRNFL), macular retinal nerve fiber layer (mRNFL), and ganglion cell layer (GCL) also decreased. OCTA indicated that the superficial and deep vascular density decreased, the foveal avascular zone (FAZ) area enlarged, and the acircularity index (AI) reduced in AGM individuals.

CONCLUSIONS

Retinal thinning and microvascular lesions have occurred before the advent of clinically detectable DR; OCT and OCTA may have the potential to detect these preclinical changes.

REGISTRATION

PROSPERO; http://www.crd.york.ac.uk/prospero/ ; No. CRD42021269885.

Low rates of optical coherence tomography utilization in the diagnosis and management of retinovascular diseases in a lower middle-income economy

Background

Optical coherence tomography (OCT) is widely used as the standard of care in evaluating macular and retinovascular diseases. However, the degree of OCT utilization is yet to be researched in a resource-limited country where wide gaps exist in access to healthcare.

Aim

To determine the rate of utilization of the OCT in diagnosis, pre-treatment, and post-treatment evaluation of macular and retinovascular diseases treated with intravitreal anti-vascular endothelial growth factor injection (IVI).

Patients and Methods

Retrospective, consecutive, and non-comparative case series of eyes diagnosed and treated from Jan 2017 to Jan 2022 for seven macular and retinovascular diseases in five eye clinics in Nigeria. Data extracted include demographics, indication for IVI, eye treated, use or non-use of OCT at the diagnosis (pre-treatment) and after the last IVI (post-treatment), and central macular thickness (CMT) of pre-treatment OCT scans.

Results

Seven hundred and forty two eyes were diagnosed with retinovascular and macular diseases (389 right eyes and 353 left eyes).The male to female ratio was 430: 312 eyes. The mean age was, 63.89 years (SD 12.58). Four hundred and fifty two eyes (60.9%) had a pre-treatment OCT, 235 eyes (31.7%) had a post-treatment OCT, and 190 eyes (25.6%) had both pre- and post-treatment OCTs. The rate of pre-treatment OCT varied with the diagnosis (P = 0.000); DME had the highest rate, 74.4%, and HRVO had the lowest, 40%. Post-treatment OCT rate varied with the diagnosis (P = 0.009); non-AMD CNVM had the highest rate, 49.1%, and PCV had the lowest, 24.6%. Pre-treatment OCT rate was influenced by clinic location (P = 0.000); higher in clinics having an OCT. Post-treatment OCT was not influenced by clinic location (P = 0.37). A CRVO eye had the highest maximum CMT (1031 microns) of all the pre treatment eyes and the lowest minimum CMT of all the pre treatment eyes was in a BRVO eye (138 microns). Mean CMT was highest in HRVO (475.33 microns) and lowest in CNVM (307.62 microns).

Conclusion

Though OCT is the standard of care for managing retinovascular and macular diseases, this research quantifies the extent of its use in Nigeria and finds it to be low. A post-treatment OCT rate of 32% suggests that urgent steps are required to improve access to OCT for IVI patients.

Advances in swept-source optical coherence tomography and optical coherence tomography angiography

Background

The fast development of swept-source optical coherence tomography (SS-OCT) and swept-source optical coherence tomography angiography (SS-OCTA) enables both anterior and posterior imaging of the eye. These techniques have evolved from a research tool to an essential clinical imaging modality.

Main text

The longer wavelength and faster speed of SS-OCT and SS-OCTA facilitate better visualization of structure and vasculature below pigmented tissue with a larger field of view of the posterior segment and 360-degree visualization of the anterior segment. In the past 10 years, algorithms dealing with OCT and OCTA data also vastly improved the image quality and enabled the automated quantification of OCT- and OCTA-derived metrics. This technology has enriched our current understanding of healthy and diseased eyes. Even though the high cost of the systems currently limited the widespread use of SS-OCT and SS-OCTA at the first beginning, the gap between research and clinic practice got obviously shortened in the past few years.

Conclusions

SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift toward more widespread adoption of new imaging technology in clinical practice.

Cynomolgus monkey's retina volume reference database based on hybrid deep learning optical coherence tomography segmentation

Cynomolgus monkeys (Macaca fascicularis) are commonly used in pre-clinical ocular studies. However, studies that report the morphological features of the macaque retina are based only on minimal sample sizes; therefore, little is known about the normal distribution and background variation. This study was conducted using optical coherence tomography (OCT) imaging to investigate the variations in retinal volumes of healthy cynomolgus monkeys and the effects of sex, origin, and eye side on the retinal volumes to establish a comprehensive reference database. A machine-learning algorithm was employed to segment the retina within the OCT data (i.e., generated pixel-wise labels). Furthermore, a classical computer vision algorithm has identified the deepest point in a foveolar depression. The retinal volumes were determined and analyzed based on this reference point and segmented retinal compartments. Notably, the overall foveolar mean volume in zone 1, which is the region of the sharpest vision, was 0.205 mm³ (range 0.154-0.268 mm³), with a relatively low coefficient of variation of 7.9%. Generally, retinal volumes exhibit a relatively low degree of variation. However, significant differences in the retinal volumes due to the monkey's origin were identified. Additionally, sex had a significant impact on the paracentral retinal volume. Therefore, the origin and sex of cynomolgus monkeys should be considered when evaluating the macaque retinal volumes based on this dataset.

Swept-source optical coherence tomography changes and visual acuity among Palestinian retinitis Pigmentosa patients: a cross-sectional study

BACKGROUND

Retinitis pigmentosa (RP) is a heterogeneous group of inherited ocular diseases that result in progressive retinal degeneration. This study aims to describe different Swept-source Optical Coherence Tomographic (SS-OCT) changes in Palestinian RP patients and to explore possible correlations with Visual Acuity (VA).

METHODS

A cross-sectional observational study was conducted on Retinitis Pigmentosa patients diagnosed with RP in a tertiary eye hospital. Full history and ocular examination were made. SS-OCT imaging was done for all eyes assessing the presence of cystoid macular edema, epiretinal membrane, macular holes, and external limiting membrane, ellipsoid zone status. Also, central macular thickness and choroidal vascular thickness were measured.

RESULTS

The study was run on 161 eyes of 81 patients; 53 males and 28 females. The average age at examination was 26.1 (6-78) years. Twenty-six eyes (16.1%) were of syndromic RP patients, mostly Usher syndrome; 20 eyes (12.4%). The mean Logaritmic minimal angle of resolution (LogMAR) of Best Corrected Visual Acuity (BCVA)of the study sample was 0.66 ± 0.7. The most prevalent change was cystoid macular edema [28 eyes, (17.4%)], followed by epiretinal membrane [17eye, (10.6%)]. A macular hole was noted only in one eye (0.6%). Ellipsoid zone and external limiting membrane were absent in 55 eyes (35.0%) and 60 eyes 37.5%. Vitreous hyperreflective foci were found in 35 eyes (43.8%). LogMAR of BCVA was associated significantly with cystoid macular edema (p = 0.001), ellipsoid zone(p = 0.001), and external limiting membrane (p = 0.001).

CONCLUSIONS

Detailed SS-OCT assessment in Palestinian patients diagnosed with RP identified different morphologies from other populations. Cystoid macular edema and vitreous hyperreflective foci may reflect signs of early or intermediate stages of the disease. Disease progression can be monitored by measuring the length/width (area) of ellipsoid zone +/- external limiting membrane and choroidal vascular thickness, which should be evaluated serially using high-resolution OCT.