Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

Influence of Strabismus Surgery on Fundus Hemodynamics Based on Swept-Source Optical Coherence Tomography Angiography Blood Flow Parameters

PURPOSE

To investigate the impact of strabismus surgery on fundus hemodynamics using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

A total of 124 patients with strabismus undergoing horizontal rectus muscle surgery were included in this non-randomized contemporaneous controlled trial. Patients were divided into unilateral recession (UR) and recession-resection (RR) groups based on the number of rectus muscles operated on. The UR group was further subdivided into lateral rectus (LR) and medial rectus (MR) subgroups. SS-OCTA imaging was performed preoperatively, and at 1 day, 1 week, and 1 month postoperatively, using a 12 × 12 mm macular scan to quantify hemodynamic parameters: vessel density (VD) of superficial capillary plexus (SCP) and deep capillary plexus (DCP), choroidal thickness (CT), choriocapillaris perfusion (CCP), choroidal vascular index (CVI), and choroidal vascular volume (CVV).

RESULTS

Horizontal rectus muscle surgery induced transient fundus hemodynamic changes, with significant differences observed near the fovea and peripheral retina, but not in the operated muscle quadrant. SCP and DCP increased in the peripheral retina postoperatively, while remaining stable near the fovea. CCP increased, with earlier changes near the fovea. CVV and CT increased at 1 week postoperatively, whereas CVI decreased, all returning to baseline by 1 month. The choroid exhibited more pronounced hemodynamic changes than the retina. RR surgery caused greater changes than UR, with LR surgery having a greater impact than MR surgery.

CONCLUSIONS

This study highlights transient ocular hemodynamic changes following horizontal rectus muscle surgery, varying by retinal region and number of muscles operated, providing new insights into fundus hemodynamics using SS-OCTA. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXX-XXX.].

Choriocapillaris impairment in dry AMD: insights from swept-source OCT angiography and associations with structural biomarkers

AIMS

To assess choriocapillaris flow deficit percentage (CCFD%) across stages of dry age-related macular degeneration (AMD) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

This cross-sectional, observational study included 270 eyes (182 patients), classified as early (70 eyes), intermediate (121 eyes) and geographic atrophy (GA, 79 eyes).Participants underwent a complete examination including macular 6×6 mm SS-OCTA scans (PLEX Elite 9000). Scans were reviewed and analysed for subretinal drusenoid deposits (SDDs), retinal pigment epithelium (RPE) atrophy size, incomplete RPE and outer retinal atrophy (iRORA) and drusen volume (3 mm). CCFD% was calculated after compensation and binarisation using Phansalkar's method (r=4-15 pixels) in various early treatment for diabetic retinopathy study sectors. Linear mixed-effects models adjusted for age evaluated associations with AMD stages and other imaging biomarkers.

RESULTS

CCFD% progressively increased with advancing dry AMD stages. Intermediate AMD eyes showed higher CCFD% than early AMD ones across all regions (p<0.001). GA eyes exhibited significantly higher CCFD% compared with early (p<0.001) and intermediate AMD eyes (p<0.001).SDDs were significantly associated with higher CCFD% in early (p<0.01) and intermediate AMD (p<0.05) for almost all regions examined, but not in GA (p>0.05). iRORA presence in iAMD and larger RPE atrophy in GA correlated with increased CCFD% (p<0.001).

CONCLUSIONS

This study provides a comprehensive reference database for CCFD% across the stages of dry AMD using SS-OCTA. CCFD% increased with AMD severity, iRORA, SDDs, particularly in early and intermediate stages, and RPE atrophy size. Our findings support CCFD% as a valuable biomarker for clinical and research applications, warranting longitudinal studies to validate its prognostic value.

Application of SS-OCTA to evaluate the effects of long-term hydroxychloroquine treatment on retinal structure and microcirculation in patients with systemic lupus erythematosus

PROPOSE

The application of swept-source optical coherence tomography angiography (SS-OCTA) technique is used to detect the effects of long-term use of hydroxychloroquine (HCQ) on retinal structure and microcirculation in patients with systemic lupus erythematosus (SLE) before visual dysfunction occurs.

METHODS

Retrospective case-control study. A total of 73 SLE patients (73 eyes) who had taken HCQ regularly for a long period of time were included as the SLE patient group, while 21 healthy individuals (21 eyes) were included as the control group. Based on the duration of HCQ use (HCQ course), the SLE patient group was divided into baseline group (6 months ≤ medication time < 1 year), low-risk group ( 1 year ≤ medication time < 5 years), and high-risk group (medication time ≥ 5 years). All participants underwent bilateral SS-OCTA macular imaging (6 mm*6 mm), slit-lamp examination, non-contact tonometry, computerized visual field (30 - 2) test, and fundus autofluorescence imaging (FAF).

RESULTS

Compared among the groups, the full-layer retinal thickness and superficial blood vessel density of the fovea, below the inner circle, temporal side of the outer circle and above the outer circle decreased in the macular area (6 mm*6 mm) in high-risk group of SLE patients, while the area and circumference of FAZ increased (P < 0.0125). Correlation analysis suggested that the duration of SLE disease and HCQ cumulative dose were negatively correlated with superficial retinal capillary plexus vessel density (SCP-VD) in the three regions of inner retina, full-layer retinal thickness in the fovea, fovea, temporal side of the inner circle, and above the inner circle (r < 0,P < 0.05), and positively correlated with the area and circumference of FAZ (r > 0,P < 0.05).

CONCLUSION

Analysis by SS-OCTA examination showed that long-term HCQ treatment had adverse effects on the inner retina, SCP-VD and FAZ parameters in subclinical SLE patients without visual impairment.

Advances in Choroid-Glaucoma Structural-Functional Correlations Using swept-source optical coherence tomography

The choroid is a highly vascularized tissue that provides the main blood flow supply, mostly oxygen and nutrients, to the retina. The choroid is thought to play an important role in the progression of glaucoma because of its special structure and rich blood flow. However, the exact mechanism remains unclear due to limitations in research techniques. In this review, the pathophysiology of glaucoma is elucidated by combining swept-source optical coherence tomography (SS-OCT) results with noninvasive angiography data to comprehensively assess the anatomy and blood flow in the choroids of glaucoma patients. Our analyses suggest that functional and structural changes in the choroid are evident in glaucoma patients as the disease progresses and that the action mechanism varies across different types of glaucoma. This review highlights the potential of SS-OCT to improve the early diagnosis and monitoring of glaucoma. Understanding the role of the choroid in glaucoma may lead to the development of new therapeutic approaches and thus facilitate the early detection, diagnosis and treatment of glaucoma.

Global trends and hotspots in artificial intelligence for high myopia: a bibliometric analysis

Purpose

This study aims to conduct a bibliometric analysis of global publications on the application of artificial intelligence (AI) in high myopia (HM).

Methods

We retrieved publications on AI in HM from the Web of Science Core Collection (WoSCC) database, MEDLINE and Chinese Science Citation Database (CSCD) with data up to 2024. The analysis focused on publication and citation trends, identifying key articles, influential countries, institutions, authors, and journals. Additionally, we explored research domains and emerging keywords.

Results

A total of 167 relevant publications were included. The first AI-related paper on HM was published in 2017, with a significant surge in 2021, followed by a consistent increase in publication and citation counts over the next 3 years. China emerged as the most productive country, with the most extensive international collaboration. East Asian authors dominated the top 10 most influential authors. Yang, Weihua and Investigative Ophthalmology & Visual Science (IOVS) contributed the most publications among authors and institutions, respectively. Keyword analysis revealed that retinal imaging-related terms remained a consistent research focus, while newly emerging keywords included "automated detection" and "childhood."

Conclusion

Recent advancements in AI applications for HM have been significant and are expected to continue. Future research will likely focus on multimodal imaging and improving algorithm accessibility. Our findings offered the first comprehensive overview of global research on AI in HM, thus providing valuable insights for researchers to understand the current status and future trends in this field.

Application of Artificial Intelligence to Deliver Healthcare From the Eye

Importance

Oculomics is the science of analyzing ocular data to identify, diagnose, and manage systemic disease. This article focuses on prescreening, its use with retinal images analyzed by artificial intelligence (AI), to identify ocular or systemic disease or potential disease in asymptomatic individuals. The implementation of prescreening in a coordinated care system, defined as Healthcare From the Eye prescreening, has the potential to improve access, affordability, equity, quality, and safety of health care on a global level. Stakeholders include physicians, payers, policymakers, regulators and representatives from industry, government, and data privacy sectors.

Observations

The combination of AI analysis of ocular data with automated technologies that capture images during routine eye examinations enables prescreening of large populations for chronic disease. Retinal images can be acquired during either a routine eye examination or in settings outside of eye care with readily accessible, safe, quick, and noninvasive retinal imaging devices. The outcome of such an examination can then be digitally communicated across relevant stakeholders in a coordinated fashion to direct a patient to screening and monitoring services. Such an approach offers the opportunity to transform health care delivery and improve early disease detection, improve access to care, enhance equity especially in rural and underserved communities, and reduce costs.

Conclusions and Relevance

With effective implementation and collaboration among key stakeholders, this approach has the potential to contribute to an equitable and effective health care system.

Diagnostic value of choroidal vascular density in predicting the progression of diabetic retinopathy

By utilizing widefield swept-source optical coherence tomography angiography (WSS-OCTA) to quantify choroidal vascular density (VD) in order to identify early fundus changes in diabetic patients and to predict the progression of diabetic retinopathy (DR). A total of 101 eyes, including patients with type 2 diabetes mellitus and controls, were included in the cross-sectional study. Diabetic patients were stratified into three groups based on disease severity: non-DR (NDR), nonproliferative DR (NPDR), and proliferative DR (PDR). Fundus images obtained through WSS-OCTA were segmented into nine 2 mm × 2 mm regions centered on the macula: supratemporal (ST), superior (S), supranasal (SN), temporal (T), central macular area (C), nasal (N), inferotemporal (IT), inferior (I), and inferonasal (IN). Changes in choroidal VD in the choriocapillaris (CC) and mid-large choroidal vasculature (MLCV) layers were evaluated in each region among patients with DR. Additionally, the diagnostic value of choroidal VD in distinguishing different stages of DR was assessed using the area under the receiver operating characteristic (ROC) curve. In comparison to the NDR group, the VD of MLCV (S) was found to decrease significantly in the NPDR group. Furthermore, the VD of CC (S) was significantly lower in the PDR group compared to the NPDR group. The VD of MLCV (IN) demonstrated potential in distinguishing between healthy eyes and those with NDR. Additionally, the VD of CC (SN) and MLCV (S, SN, C, I) showed relatively high area under the curve (AUC) values in discriminating between NDR and NPDR. Lastly, the VD of CC (S) exhibited good diagnostic accuracy in distinguishing between NPDR and PDR patients. As DR advances, MLCV and CC are sequentially compromised to varying degrees. In clinical diagnosis, the VD of the IN region in the MLCV layer serves as a more sensitive early imaging biomarker for detecting preclinical DR, while a decrease in the VD of the S region in the CC layer indicates the onset of PDR.

MULTIPLE CHOROIDAL NEOVASCULARIZATIONS IN CHOROIDAL OSTEOMA TREATED WITH ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR INJECTIONS: A 6-YEAR FOLLOW-UP CASE REPORT

PURPOSE

The objective of this study was to report a case of multiple choroidal neovascularizations (CNVs) secondary to choroidal osteoma injected with a total of 13 anti-vascular endothelial growth factor drugs over a long-term follow-up of 6-year period.

METHODS

This was a case report.

RESULTS

A 29-year-old woman presented with a peripapillary choroidal osteoma in her left eye with the best-corrected visual acuity of 20/25. After 2 years of follow-up, two foci of CNV (one was at the infranasal of the optic disc and the other was near the subtemporal vascular arch) and massive subretinal hemorrhage developed overlying the osteoma, causing decreased best-corrected visual acuity of 20/33. The patient was treated with four consecutive intravitreal injections of conbercept, and the two CNVs regressed with the best-corrected visual acuity recovered to 20/25. While 17 months later, the third CNV lesion locating at the fovea appeared and nine more injections of aflibercept were given during which repeated recurrence of it occurred. At the last follow-up, 6 years from baseline, all the three CNV foci were controlled, with the final best-corrected visual acuity of 20/33.

CONCLUSION

Multiple CNVs may appear simultaneously at different locations in one osteoma, and prompt treatment with intravitreal anti-vascular endothelial growth factor may be a good option to control the progression and recurrence of these CNVs. Long-term follow-up and multimodal imaging are vital in the management of CO-associated CNV.

Prospective and dichotomous study of biomarkers with swept-source OCT and OCT-angiography in naive patients with diabetic macular edema

BACKGROUND

We used state-of-the-art high-resolution retinal imaging to explore the treatment (loading dose of aflibercept) of diabetic macular edema (DME) among treatment-naive patients. Swept-source (SS) OCT and OCT-Angiography (SS-OCTA) were performed, and a dichotomous analysis was conducted to compare responders and treatment-resistant patients (responsive and resistant). Furthermore, treatment responses were evaluated based on the subdivision of choroidal thickness.

MATERIALS AND METHODS

This prospective, noncomparative, interventional case series study examined the following biomarkers: best-corrected visual acuity (BCVA), central macular thickness (CMT), central choroidal thickness (CCT), avascular area of the superficial plexus (AASP), avascular area of the deep plexus (AADP), and vessel density (VD). Data from the baseline and 4-month examinations were compared.

RESULTS

Twenty-eight eyes from 25 patients were included. Significant improvements were observed in BCVA (0.7250 ± 0.23 to 0.3957 ± 0.21; p < 0.000), CMT µm (339.04 ± 66.19 to 265.21 ± 55.75; p < 0.000), CCT µm (221.71 ± 69.69 to 209.07 ± 70.92; p < 0.000), VD (17.90 ± 7.82 to 15.35 ± 5.80; p < 0.038), AASP µm2 (235,374 ± 91,299 to 157,326 ± 77,815; p < 0.000) and AADP µm2 (996,335 ± 1,000,047 to 362,161 ± 277,225; p < 0.000). Dichotomous analysis revealed that 15 patients were responsive (53.57%), and 13 resistant (46.43%). There were no significant differences between any of the pretreatment biomarkers. In the subdivision of choroidal thickness, which ranged from 211 to 270 µm (group 3), we found greater reductions in the CCT, AADP and CD. The choroidal thickness ranged from 181 to 210 µm (group 2): BCVA and AASP exhibited the greatest reductions.

CONCLUSION

BCVA, CMT, CCT, AASP, AADP and VD were improved after treatment. The pretreatment biomarkers did not predict treatment response between the responsive and resistant. Regarding choroidal stratification, values within the normal range of CCT showed the greatest reductions, indicating that these values may be more responsive to treatment. Notably, this is the first study to analyze biomarkers provided by SS OCT and OCTA, stratify the choroid, and perform a dichotomous analysis.

Recent advances and applications of optical coherence tomography angiography in diabetic retinopathy

Introduction

Optical coherence tomography angiography (OCTA), a noninvasive imaging technique, is increasingly used in managing ophthalmic diseases like diabetic retinopathy (DR). This review examines OCTA's imaging principles, its utility in detecting DR lesions, and its diagnostic advantages over fundus fluorescein angiography (FFA).

Methods

We systematically analyzed 75 articles (2015-2024) from the Web of Science Core Collection, focusing on OCTA's technical principles, clinical applications in DR diagnosis, and its use in diabetes mellitus (DM) without DR and prediabetes. The use of artificial intelligence (AI) in OCTA image analysis for DR severity evaluation was investigated.

Results

OCTA effectively identifies DR lesions and detects early vascular abnormalities in DM and prediabetes, surpassing FFA in noninvasiveness and resolution. AI integration enhances OCTA's capability to diagnose, evaluate, and predict DR progression.

Discussion

OCTA offers significant clinical value in early DR detection and monitoring. Its synergy with AI holds promise for refining diagnostic precision and expanding predictive applications, positioning OCTA as a transformative tool in future ophthalmic practice.

A Quantitative Normative Database for Expanded Field Swept-source OCT Angiography in the Pediatric Population

BACKGROUND AND OBJECTIVE

To report quantitative vascular metrics of healthy control eyes of children, using expanded field swept-source optical coherence tomography angiography (SS-OCTA), as a baseline to compare with pathologic findings.

PATIENTS AND METHODS

A cross-sectional observational study of healthy eyes of children (age 6 to 18) who were imaged on the PLEX Elite 9000 instrument at 100-kHz scanning rate using 3 × 3-mm, 6 × 6-mm, and 12 × 12-mm protocols centered on the fovea (2019 to 2023). Scans were uploaded to the ARI Network (Zeiss Portal v5.4) and processed with the macular density algorithm (v.0.7.3.3) to calculate vessel density (VD) and vessel skeletonized density (VSD) in the superficial capillary plexus (SCP), deep capillary plexus, and whole retina (WR) and foveal avascular zone (FAZ) metrics.

RESULTS

Forty-eight eyes of 39 children (72% male) were included. Median age was 14 years (interquartile range 10 to 16). Male sex was associated with lower VD and VSD compared to female sex (P < 0.05). Older age was associated with higher VD and VSD (6 × 6-mm) (P < 0.05) and lower FAZ circularity (P = 0.017). Non-Hispanic White children had a lower VD and VSD of the SCP in the inner superior ring (3 × 3-mm), a higher VD and VSD of the SCP and WR in the central ring (6 × 6-mm), and a lower FAZ area (6 × 6-mm) (P < 0.05).

CONCLUSIONS

This study presents a database for expanded field vascular metrics in pediatric subjects across various angiogram sizes. The VD increases throughout childhood and the FAZ circularity diminishes. Future studies using SS-OCTA will need to account for influencing factors such as sex, age, race, and ethnicity. [Ophthalmic Surg Lasers Imaging Retina 2025;56:212-218.].

The evaluation of the macular and optic nerve head microvasculature in amblyopic and non-amblyopic patients with constant exotropia in comparison to healthy controls

OBJECTIVE

To evaluate the retinal microvascular changes in strabismic amblyopia and compare them to the strabismic cases without amblyopia and controls.

DESIGN

Cross-sectional study.

PARTICIPANTS

Three groups of patients, including 25 amblyopic cases with exotropia (XT), 25 constant XT cases without amblyopia, and 25 healthy subjects as controls, are included in the study. Both eyes of the included participants are evaluated.

METHODS

All the patients underwent a thorough ophthalmic examination, BCVA assessment, and macular and optic nerve head OCTA with the AngioVue™ Imaging System.

MAIN OUTCOME MEASURES

The vascular density (VD) of various layers (Deep and superficial capillary plexus (DCP and SCP) in different regions of the macula, optic nerve head, and FAZ area were evaluated as the target variables.

RESULTS

42 females and 33 males with a mean age of 32.2 (95%CI:29.8-34.6) entered our study. The median exotropia in both groups was 35 PD. The parafoveal DCP VD was significantly lower in both eyes of amblyopic cases than in controls (53.56 and 52.31 vs. 56.13%, p:0.021, <0.001). The parafoveal SCP VD was only lower in the dominant eye of the amblyopic cases than in the controls (50.53 vs. 53.54%, p:0.002). The foveal and peripapillary VD showed no significant difference between the groups. The FAZ area was significantly larger in amblyopic eyes than the fellow eyes (0.250 vs. 0.194 mm2, p:0.025) and correlated with worse BCVA (Correlation Coefficient: 0.358, p: 0.011).

CONCLUSIONS

The amblyopia could be accompanied by a lower parafoveal DCP VD and a larger FAZ area in strabismic amblyopia.

Accidental diode laser-induced full-thickness macular hole: a case report

Accidental ocular injuries caused by laser devices used in non-medical settings are rare but potentially vision-threatening. This case report describes a 24-year-old woman who sustained a full-thickness macular hole (FTMH) in the right eye following accidental diode laser exposure during a hair removal procedure at a beauty center. The injury occurred when the laser probe was inadvertently activated, striking the patient's unprotected eye. The patient presented with profound visual loss in the affected eye, with visual acuity reduced to the level of hand motion. Comprehensive ophthalmological examination revealed a FTMH in the right eye, confirmed by optical coherence tomography (OCT), which showed complete disruption of the foveal retinal layers and cystic changes at the margins of the hole. The patient underwent surgical intervention with pars plana vitrectomy (PPV), internal limiting membrane (ILM) peeling, and gas tamponade to promote macular hole closure and restore retinal integrity. Despite successful anatomical closure of the macular hole, the patient's visual prognosis remained guarded due to extensive photothermal damage to the retinal pigment epithelium and photoreceptor layers. This case underscores the devastating consequences of inadequate laser safety protocols in non-medical environments, the critical role of OCT in diagnosing and managing laser-induced retinal injuries, and the importance of timely surgical intervention.

Comparison of choroidal thickness and vascularity in patients with subretinal drusenoid deposits and large drusen using swept-source optical coherence tomography

PURPOSE

The aim of this study is to assess the choroidal features in patients diagnosed with non-advanced age-related macular degeneration (AMD) using Swept-source Optical Coherence Tomography (SS-OCT) and compare the findings of those with subretinal drusenoid deposits (SDD) and those with large drusen.

METHODS

Individuals aged 50 years and above, presenting with either SDD or large drusen alongside non-advanced AMD, underwent a thorough ophthalmic assessment. OCT scans were acquired using SS-OCT. Choroidal thickness (CT) maps within the early treatment diabetic retinopathy study (ETDRS) subfields were obtained. Choroidal vascularity index (CVI) was obtained from a foveal horizontal OCT scan, and it was determined as the ratio of luminal area to the total choroidal area. The data obtained were compared between the groups.

RESULTS

Forty-three eyes of 27 patients with SDD and 40 eyes of 21 patients with large drusen were included in the study. The mean age was 72.0 ± 8.6 years in the SDD group and 71.3 ± 5.6 years in the large drusen group with no significant difference (p = 0.717). In the choroidal thickness maps CT and CT in all ETDRS subfields were significantly lower in SDD group compared to the large drusen group. CVI values were not significantly different between SDD (0.628 ± 0.18) and large drusen groups (0.629 ± 0.20) (p = 0.812).

CONCLUSION

Non-advanced AMD patients with SDD exhibited reduced choroidal thickness compared to those with large drusen. Choroidal vascularity index did not significantly differ, suggesting that choroidal thickness may play a more substantial role than vascularity changes in the pathogenesis of SDD.

ASSESSING THE REPEATABILITY OF INNER CHOROID FLOW DEFICIT PERCENTAGE IN INTERMEDIATE AGE-RELATED MACULAR DEGENERATION AND CONTROLS: A Comparative Study Between Different Post-Processing Approaches

PURPOSE

To assess repeatability of macular inner choroid flow deficit percentage in intermediate age-related macular degeneration and controls using various postprocessing approaches.

METHODS

Cross-sectional, observational study. The authors included 1) 22 intermediate age-related macular degeneration and 24 control eyes, with 2) age >50 years, 3) visual acuity >20/32, and 4) no additional ocular and systemic confounders. Participants underwent four consecutive 6 × 6-mm optical coherence tomography angiography scans (2 acquired at 100-kHz and 2 at 200-kHz speed; PLEX Elite 9000) for intrasession analysis. Same protocol was repeated after 30 minutes for intersession analysis. Three slabs of different thicknesses were generated underneath Bruch membrane (4-14, 4-19, 4-24 µ m). All slabs were processed with: 1) binarization-only using Phansalkar method (r = 4-15 pixels); 2) compensation + binarization; 3) averaging + binarization; 4) averaging + compensation + binarization. Inner choroid flow deficit percentage was measured within 3-mm and 5-mm circles, and measurements were repeated after excluding drusen areas. Repeatability was analyzed with generalized linear mixed-effects models, intraclass correlation coefficients, and Levene variance test.

RESULTS

Most postprocessing approaches demonstrated high repeatability (intraclass correlation coefficient >0.75) with no significant test-retest differences ( P > 0.05). Compensation + binarization of 15- µ m slabs at 200 kHz showed the highest repeatability (intraclass correlation coefficient: 0.96-0.98). Excluding drusen did not significantly affect inner choroid flow deficit percentage measurements ( P > 0.05), showing increased intraclass correlation coefficients for 10-µm-thick and binarized-only slabs.

CONCLUSION

Strong repeatability can be achieved with various postprocessing methods for assessing inner choroid flow deficit percentage, especially with compensation + binarization of 15- µ m slabs acquired at 200 kHz. Drusen removal does not seem to affect repeatability in intermediate age-related macular degeneration when using a swept-source device, except for specific settings. These results contribute to refining choriocapillaris assessment, paving the way for future applications.

Clinical and imaging characteristics associated with foveal neovascularization in proliferative diabetic retinopathy

PURPOSE

To assess the prevalence of foveal neovascularization (FNV) and its associated clinical features in proliferative diabetic retinopathy (PDR) eyes.

METHODS

Cross-sectional observational study. Participants underwent ultra-widefield photography, optical coherence tomography (OCT), and swept-source OCT angiography (SS-OCTA). FNV was defined as a hyperreflective lesion breaching the internal limiting membrane and displaying flow signal on OCTA, within 1-mm of foveal avascular zone. Vascular metrics were obtained from the ARI Network portal. Ischemic index (ISI) and inner choroid flow deficit percentage were calculated using FIJI from 12 × 12 and 6 × 6-mm scans, respectively. Logistic regression models were used to compare eyes with and without FNV.

RESULTS

We included 249 eyes of 164 patients (age: 58 [50-65] years). FNV was identified in 20 eyes (8%). Univariate logistic regression revealed significant associations between FNV and younger age (p = 0.03), higher maximal HbA1c (p = 0.04), worse visual acuity (VA) (p = 0.01), presence of disorganization of retinal inner layers (DRIL) (p = 0.01), no macular posterior vitreous detachment (PVD) (p = 0.03), neovascularization elsewhere (NVE) and at the disc (NVD) (p = 0.01 and p = 0.001), and greater ISI (p = 0.04). In multivariable analysis, a significant association remained between FNV and worse VA (p = 0.04), NVD (p < 0.001), DRIL (p < 0.001), and absence of macular PVD (p = 0.01). No associations were found with SS-OCTA vascular metrics.

CONCLUSIONS

This study provides a comprehensive characterization of FNV in PDR. FNV was identified in 8% of our cohort, being more prevalent in younger patients with severe PDR, as evidenced by NVD and DRIL presence. The absence of macular PVD may explain its association with younger age.

KEY MESSAGES

What is known • Neovascularization at the fovea occurs rarely in proliferative diabetic retinopathy. • OCT and OCT-angiography can be used to evaluate foveal neovascularization, which may be associated with choroidal vascular abnormalities. What is new • Foveal neovascularization was seen in 8% of eyes with proliferative diabetic retinopathy in this cohort. • Risk factors for foveal neovascularization included younger age, absence of macular posterior vitreous detachment, presence of neovascularization of the disc, and presence of disorganization of retinal inner layers. • We did not identify an association between foveal neovascularization and choroidal perfusion abnormalities in this study.

Correlation Between Photoreceptor and Vascular Parameters in Diabetic Retinopathy Using Adaptive Optics

BACKGROUND AND OBJECTIVE

This study aimed to investigate correlations between photoreceptor and vascular parameters in varying stages of diabetic retinopathy (DR) using adaptive optics (AO) imaging.

PATIENTS AND METHODS

In this single-center, prospective cohort study, 29 participants (46 eyes) were classified into control/mild non-proliferative DR (NPDR), moderate/severe NPDR, and proliferative DR. AO images of photoreceptors and retinal vasculature were analyzed, and Spearman's correlation (ρ) was used to assess relationships between photoreceptor density and vascular parameters.

RESULTS

Higher cone density was inversely associated with total vessel (ρ = 0.22, P = 0.03) and lumen diameters (ρ = -0.24, P = 0.01), while higher dispersion was associated with total vessel (ρ = 0.19, P = 0.06) and lumen diameters (ρ = 0.21, P = 0.04). These associations were primarily significant in mild NPDR. No significant correlations were found in advanced DR stages.

CONCLUSION

This study underscores intricate neurovascular correlations in early-stage DR, suggesting these parameters may aid in early disease detection. Further research is needed to understand whether similar correlations exist in advanced DR. [Ophthalmic Surg Lasers Imaging Retina 2025;56:150-158.].

Optical Coherence Tomography Angiography Analysis of Peripapillary Choroidal Microvascular Density in Normal Tension Glaucoma and Primary Open Angle Glaucoma

PRCIS

Glaucoma patients had a reduction in the inner annulus peripapillary choroidal microvascular density (PCMD) that became worse as the glaucoma severity progressed, which might provide new evidence supporting the vascular theory.

PURPOSE

To compare PCMD among normal tension glaucoma (NTG), primary open angle glaucoma (POAG), and healthy controls using optical coherence tomography (OCT) angiography (OCTA).

MATERIALS AND METHODS

The study included 40 POAG, 25 NTG, and 33 healthy controls. All subjects underwent OCT and OCTA testing. The inner annulus and outer annulus PCMD, as well as peripapillary vessel density (VD), were calculated. One-way analysis of variance was used to compare the vascular parameters of the 3 groups. Pearson correlation analysis or Spearman correlation test was used to evaluate the correlation between PCMD and glaucomatous severity factors. The spatial positional relationship between PCMD and corresponding peripapillary retinal nerve fiber layer (RNFL) thickness and visual field (VF) mean deviation (MD) was also assessed.

RESULTS

The average and 4 quadrants of the inner annulus PCMD and peripapillary VD in the 2 glaucomatous groups were significantly lower than in normal eyes ( P <0.05). Strong correlations were found between inner annulus PCMD and VF MD, peripapillary VD, and RNFL in POAG patients. Similarly, the inner annulus PCMD in NTG patients was strongly correlated with peripapillary VD and RNFL (all r >0.5). Strong positional correlations were found between inner superior quadrantal PCMD and RNFL thickness in both POAG and NTG patients ( r =0.566 and 0.731, respectively). Likewise, inner inferior quadrantal PCMD exhibited a strong correlation with RNFL thickness in POAG patients ( r =0.608). Strong positional correlations were also found between inner superior PCMD and VF MD in both POAG and NTG patients ( r =0.589 and 0.622, respectively). Inner inferior PCMD exhibited a moderate correlation with VF MD in both POAG and NTG patients ( r =0.487 and 0.440, respectively).

CONCLUSION

The study found that the inner annulus PCMD decreased to varying degrees in NTG and POAG patients. The inner annulus PCMD was closely related to the structural and visual function parameters of glaucoma in both NTG and POAG. Furthermore, inner PCMD demonstrated a spatial correlation with corresponding RNFL thickness and VF MD.

Evaluation of the effects of ND: YAG laser capsulotomy on choroidal thickness and choroidal vascularity index

Posterior capsular opacification (PCO) is a common complication after cataract surgery, which is commonly treated using neodymium: yttrium-aluminum-garnet (Nd-YAG) laser capsulotomy. The purpose of this study is to investigate the impact of Nd-YAG laser capsulotomy on retinal and choroidal structures. Thirty-four eyes from 32 patients with PCO were included. Patients underwent Nd-YAG laser capsulotomy, and assessments were performed preoperatively, at 1st week, and 1st month postoperatively. OCT scans were acquired using Swept-source Optical Coherence Tomography (SS OCT). Choroidal thickness (CT) maps within the early treatment diabetic retinopathy study (ETDRS) subfields were obtained. Choroidal Vascularity Index (CVI) was calculated from OCT scans using Image J software. The preoperative, postoperative first week and first month measurements were compared. The mean age of patients was 68.7 ± 8.6 years. Visual acuity significantly improved postoperatively (p < 0.001), while IOP remained unchanged (p = 0.170). No significant change in central macular thickness (CMT) was observed across time points. CVI significantly increased postoperatively (p = 0.004). Choroidal thickness remained stable in most sectors, except for significant reduction in the inner inferior sector at 1 month (p = 0.025). Nd-YAG laser capsulotomy did not affect central macular thickness but caused localized change in choroidal thickness. Increased CVI was found which may be linked to postoperative inflammation. These findings suggest capsulotomy may affect choroidal structure and vasculature.

Coronary artery and retinal vascularization by optical coherence tomography angiography: are eyes the window to the heart?

PURPOSE

Coronary artery disease (CAD) is the leading cause of death in the United States and its assessment still relies on invasive diagnostic procedures requiring contrast, such as coronary angiography (CAG) or computed tomography angiography (CCTA). The retinal vasculature is the only microvascular site in the human body that can be assessed non-invasively, and it has been described as a promising method for predicting cardiovascular risk since the classification of hypertensive retinopathy in the 19th century. Unfortunately, most classifications still rely on qualitative findings, which exhibit high rates of interobserver and intraobserver variability. With advances in ophthalmology exams, particularly the advent of optical coherence tomography angiography (OCTA), the capability of quantitatively assessing retinal vasculature can enable a more reliable non-invasive exam that could aid in estimating cardiovascular risk and assessing coronary lesions. This review aims to provide an extensive overview of the available evidence establishing the correlation of retinal and choroidal microvascular damage observed in OCTA and parameters such as coronary stenosis grade, number of affected vessels and scores like Gensini and SYNTAX evaluated via CAG or CCTA.

METHODS

Review of the literature published until December 2024 on PubMed/MEDLINE, SCOPUS and EMBASE by searching "optical coherence tomography angiography" or "OCTA" AND "Coronary artery disease" or "Coronary heart disease".

RESULTS

Findings from sixteen studies suggest a potential correlation between vascular parameters in OCTA and results from coronary exams. Reductions in vessel density analysis of the retinal plexus, especially the superficial capillary plexus (SCP), could improve patient selection and diagnostic yield for more invasive diagnostic procedures, such as CAG and CCTA.

CONCLUSION

OCTA is a non-invasive technology that can provide visualization and quantification of retinal microvascular disfunction that may correlate with macrovascular disease, particularly in the coronary circulation. Longitudinal assessment of quantitative OCTA parameters may provide biomarkers for monitoring CAD patients over time.

Expanded Field OCT Angiography Biomarkers for Predicting Clinically Significant Outcomes in Non-Proliferative Diabetic Retinopathy

PURPOSE

To evaluate the utility of extended field swept-source Optical Coherence Tomography Angiography (SS-OCTA) imaging biomarkers in predicting the occurrence of clinically significant outcomes in eyes with Non-Proliferative Diabetic Retinopathy (NPDR).

DESIGN

Retrospective clinical case-control study.

METHODS

Single-center clinical study. Eighty-eight eyes with NPDR from 57 participants (median age: 64.0 years; mean duration of diabetes: 15.8 years) with at least 2 consecutive SS-OCTA scans over a follow-up period of at least 6 months were included. The presence of intraretinal microvascular abnormalities (IRMAs) at baseline and the stability of IRMAs during follow-up period on 12 × 12-mm angiograms were evaluated. Baseline nonperfusion ischemia index (ISI) and other SS-OCTA metrics were calculated on FIJI and ARI Network. Significant clinical outcomes were defined as occurrence of one or more of the following events at the last available clinical visit:1. significant DR progression (2-step DR progression or progression to proliferative DR (PDR)); 2) development of new center-involving diabetic macular edema (CI-DME); and 3) initiation of treatment with PRP or anti-VEGF injections during the follow-up period. Mixed-effects Cox regression models was used to explore these outcomes.

RESULTS

Following a clinical follow-up period lasting 25.1 ± 10.8 months, we observed significant clinical outcomes in 17 eyes (19.3%). Among these, 7 eyes (8.0%) experienced significant progression and 4 eyes (4.5%) developed CI-DME. Anti-VEGF injections were initiated in 15 eyes (17.0%), while PRP was initiated in 2 eyes (2.3%). Upon adjusting for age, the duration of DM, and prior Anti-VEGF treatments, our analysis revealed that non-stable IRMAs during the follow-up periods and a higher ischemia index at baseline were significantly associated with the occurrence of significant clinical outcomes with HRs of 3.88 (95% CI: 1.56-9.64; p = .004) and 1.05 (95% CI: 1.02-1.09; p = .004), respectively.

CONCLUSIONS

In conclusion, NPDR eyes with non-stable IRMAs over time and more ischemia at baseline are in higher risk of developing significant clinical outcomes. Our findings suggest that expanded field SS-OCTA may offer additional prognostic benefits for clinical DR staging and predicting high-risk patients.

Recent advances of photodiagnosis and treatment for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) are the most common type of head and neck tumor that severely threatens human health due to its highly aggressive nature and susceptibility to distant metastasis. The diagnosis of HNSCC currently relies on biopsy and histopathological examination of suspicious lesions. However, the early mucosal changes are subtle and difficult to detect by conventional oral examination. As for treatment, surgery is still the primary treatment modality. Due to the complex anatomy and the lack of intraoperative modalities to accurately determine the incision margins, surgeons are in a dilemma between extensive tumor removal and improving the quality of patient survival. As more knowledge is gained about HNSCC, the increasing recognition of the value of optical imaging has been emphasized. Optical technology offers distinctive possibilities for early preoperative diagnosis, intraoperative real-time visualization of tumor margins, sentinel lymph node biopsies, phototherapy. Fluorescence imaging, narrow-band imaging, Raman spectroscopy, optical coherence tomography, hyperspectral imaging, and photoacoustic imaging have been reported for imaging HNSCC. This article provides a comprehensive overview of the fundamental principles and clinical applications of optical imaging in the diagnosis and treatment of HNSCC, focusing on identifying its strengths and limitations to facilitate advancements in this field.

Analysis of the effect of congenital unilateral trochlear nerve paresis on retinal vascular density: a retrospective study

PURPOSE

To use swept-source optical coherence tomography angiography (SS-OCTA) to investigate the alterations in retinal vascular density (VD) in patients presenting with congenital unilateral trochlear nerve palsy.

METHODS

The medical records of patients diagnosed with congenital unilateral trochlear nerve palsy and those of a healthy control group were reviewed retrospectively. Comprehensive ocular examinations and SS-OCTA imaging were conducted. The study population was divided into three subgroups of eyes: paretic eyes, fellow eyes, and controls. All participants underwent comprehensive ophthalmic examinations, which included assessments of ocular motility, cycloplegic refraction, and axial length measurement. Various strabismus tests-the cover-uncover test, prism and alternate cover test, Krimsky test, and Parks-Bielschowsky test-were conducted to confirm the diagnosis and evaluate the extent of the condition.

RESULTS

A total of 34 patients and 39 healthy controls were included. Sex and age distributions were similar between groups. Significant differences were observed in central VD of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) between paretic eyes, fellow eyes, and control eyes. The fellow eye exhibited lower central VD compared to the paretic and control eyes. Inverse correlations between deviation angle and VD were noted in different SCP and DCP quadrants in paretic eyes.

CONCLUSIONS

In our study cohort, there were significant changes in retinal VD in fellow eyes of patients with trochlear nerve palsy, which we speculate may be related to compensatory head position.

Multi-modality imaging technologies and machine learning for non-invasive, precise assessment of rabbit endometrium

Developing a minimally invasive, real-time diagnostic tool to accurately assess endometrial conditions is critical to increasing pregnancy rates in assisted reproductive technology (ART). In this research, fiberoptic bronchoscopy and optical coherence tomography (OCT) were used before and after alcohol injury and human chorionic gonadotropin (hCG)-induced pseudopregnancy to monitor changes in the rabbit endometrium. Histological analysis and electron microscopy were performed on 1 cm uterine sections while simultaneously training a conditional generative adversarial network (cGAN) to convert OCT images into virtual hematoxylin and eosin H&E stained sections. By combining these optical elements, we have managed to non-invasively observe changes in the endometrium at different stages. Traditional endoscopy assesses surface changes such as mucosal color changes, congestion, and fibrous adhesions, while OCT provides detailed views of superficial and submucosal changes and can correspond to pathological H&E sections. Machine learning improves OCT by converting images to H&E format, enabling real-time, non-invasive assessment of endometrial status and improving the accuracy of endometrial receptivity assessment.

Comparison of macular retinal thickness measurements using spectral-domain and swept-source optical coherence tomography in healthy eyes

Aim

This study compares retinal thickness measurements in healthy eyes using one SD-OCT and two SS-OCT devices to assess differences and consistency for clinical application.

Methods

Forty-eight eyes with a mean age of 28.15 ± 8.85 years were enrolled. Retinal thickness was measured using Heidelberg Spectralis SD-OCT, Svision VG200 SS-OCT, and TowardPi En Face SS-OCT. Normally distributed data were presented as mean ± SD; non-normal data as median (P25-P75). Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to assess agreement, with a 7 μm error threshold.

Results

Significant differences were found between the three devices (p < 0.001). SD-OCT measurements were consistently lower than SS-OCT (p < 0.001), while the two SS-OCT devices showed no significant differences except in the nasal region (p = 0.006). ICC values between SD-OCT and SS-OCT devices were low (0.125-0.532), while SS-OCT devices showed better agreement (ICC: 0.369-0.922). Bland-Altman analysis found only 8.33% of SD-OCT and SS-OCT measurements within the 7 μm error range, compared to 81.25-83.33% for SS-OCT devices.

Conclusion

The measurements of macular retinal thickness using SD-OCT and SS-OCT devices showed poor consistency and cannot be used interchangeably. However, measurements obtained from different SS-OCT devices demonstrated good consistency. To enhance the accuracy of results, it is recommended to maintain consistency in the devices used for follow-up examinations in the same patient.

Trajectories of choriocapillaris perfusion in healthy individuals and patients with diabetes mellitus: a prospective cohort study

PURPOSE

To evaluate the longitudinal rate of choriocapillaris flow deficits (CFD) in healthy participants and patients with diabetes mellitus.

METHODS

This prospective cohort study included healthy individuals and diabetic patients without diabetic retinopathy (non-DR) or with mild-to-moderate non-proliferative DR (NPDR). The swept-source optical coherence tomography angiography (OCTA) was adopted for quantifying CFD annually, and linear mixed models were used to analyse the CFD change and its 95% CI overtime.

RESULTS

A total of 1025 individuals were included, including 465 healthy controls, 454 in the non-DR group and 106 in the NPDR group. Significant increase in CFDs was observed in NPDR group (0.423%, 95% CI 0.230% to 0.616%) and non-DR group (0.319%, 95% CI 0.225% to 0.412%), which were higher than the CFD in healthy controls (0.173%, 95% CI 0.079% to 0.266%). After adjusting for other factors, the non-DR and NPDR group had a greater annual elevation of CFD by 0.171% (95% CI 0.060% to 0.283%; p=0.003) and 0.258% (95% CI 0.068% to 0.449%; p=0.008) in comparisons with controls. Furthermore, higher serum creatinine and glycated haemoglobin levels, poorer best-corrected visual acuity, lower OCTA image quality scores and smaller CFD at baseline were independently related to accelerated CFD worsening (all p<0.05).

CONCLUSIONS

The CFD among healthy individuals and patients with diabetes increased consistently overtime, regardless of the presence or absence of DR, suggesting that CFD alterations could be an early indicator of microvascular complications, potentially aiding in the earlier DR detection.

Photoreceptor metabolic window unveils eye-body interactions

Photoreceptors are specialized neurons at the core of the retina's functionality, with optical accessibility and exceptional sensitivity to systemic metabolic stresses. Here we show the ability of risk-free, in vivo photoreceptor assessment as a window into systemic health and identify shared metabolic underpinnings of photoreceptor degeneration and multisystem health outcomes. A thinner photoreceptor layer thickness is significantly associated with an increased risk of future mortality and 13 multisystem diseases, while systematic analyses of circulating metabolomics enable the identification of 109 photoreceptor-related metabolites, which in turn elevate or reduce the risk of these health outcomes. To translate these insights into a practical tool, we developed an artificial intelligence (AI)-driven photoreceptor metabolic window framework and an accompanying interpreter that comprehensively captures the metabolic landscape of photoreceptor-systemic health linkages and simultaneously predicts 16 multisystem health outcomes beyond established approaches while retaining interpretability. Our work, replicated across cohorts of diverse ethnicities, reveals the potential of photoreceptors to inform systemic health and advance a multisystem perspective on human health by revealing eye-body connections and shared metabolic influences.

A Survey on Optical Coherence Tomography-Technology and Application

This paper reviews the main research on Optical Coherence Tomography (OCT), focusing on the progress and advancements made by researchers over the past three decades in its methods and medical imaging applications. By analyzing existing studies and developments, this review aims to provide a foundation for future research in the field.

New Directions for Ophthalmic OCT - Handhelds, Surgery, and Robotics

The introduction of optical coherence tomography (OCT) in the 1990s revolutionized diagnostic ophthalmic imaging. Initially, OCT's role was primarily in the adult ambulatory ophthalmic clinics. Subsequent advances in handheld form factors, integration into surgical microscopes, and robotic assistance have expanded OCT's utility and impact outside of its initial environment in the adult outpatient ophthalmic clinic. In this review, we cover the use of OCT in the neonatal intensive care unit (NICU) environment with a handheld OCT, recent developments in intraoperative OCT for data visualization and measurements, and recent work and demonstration of robotically aligned OCT systems outside of eye clinics. Of note, advances in these areas are a legacy of our colleague, the late Joseph Izatt. OCT has been an important innovation for ocular diagnostics, and these advances have helped it continue to extend in new directions.

SFNet: Spatial and Frequency Domain Networks for Wide-Field OCT Angiography Retinal Vessel Segmentation

Automatic segmentation of blood vessels in fundus images is important to assist ophthalmologists in diagnosis. However, automatic segmentation for Optical Coherence Tomography Angiography (OCTA) blood vessels has not been fully investigated due to various difficulties, such as vessel complexity. In addition, there are only a few publicly available OCTA image data sets for training and validating segmentation algorithms. To address these issues, we constructed a wild-field retinal OCTA segmentation data set, the Retinal Vessels Images in OCTA (REVIO) dataset. Second, we propose a new retinal vessel segmentation network based on spatial and frequency domain networks (SFNet). The proposed model are tested on three benchmark data sets including REVIO, ROSE and OCTA-500. The experimental results show superior performance on segmentation tasks compared to the representative methods.

Extensive macular atrophy with pseudodrusen-like appearance (EMAP) clinical characteristics, diagnostic criteria, and insights from allied inherited retinal diseases and age-related macular degeneration

Extensive macular atrophy with pseudodrusen-like appearance (EMAP) was first described in France in 2009 as a symmetric and rapidly progressive form of macular atrophy primarily affecting middle-aged individuals. Despite the recent identification of a significant number of cases in Italy and worldwide, EMAP remains an underrecognized condition. The clinical triad typical of EMAP consists of vertically oriented macular atrophy with multilobular borders, pseudodrusen-like deposits across the posterior pole and mid-periphery, and peripheral pavingstone degeneration. Nonetheless, recent research has portrayed EMAP as a highly stage-dependent condition, allowing the identification of novel disease hallmarks, including a diffuse separation between the Bruch's membrane and the retinal pigment epithelium, along with consistent sparing of a region temporal to the macula. Additionally, retinal electrophysiology is particularly useful in distinguishing EMAP from age-related macular degeneration (AMD). Supported by unpublished data from the largest EMAP cohorts worldwide, this review aims to provide a comprehensive and updated description of EMAP, now recognized as a severely blinding disease characterized by diffuse chorioretinal atrophy and photoreceptor dysfunction. Furthermore, we propose a set of diagnostic criteria that incorporate clinical, imaging, and functional tests, to facilitate the recognition of this clinical entity. Lastly, we aim to shed light on its pathogenesis by comparing it with AMD and monogenic retinal disorders exhibiting similar phenotypes.

-Net: Retinal OCTA Image Stitching via Multi-Scale Representation Learning and Dynamic Location Guidance

Optical coherence tomography angiography (OCTA) plays a crucial role in quantifying and analyzing retinal vascular diseases. However, the limited field of view (FOV) inherent in most commercial OCTA imaging systems poses a significant challenge for clinicians, restricting the possibility to analyze larger retinal regions of high resolution. Automatic stitching of OCTA scans in adjacent regions may provide a promising solution to extend the region of interest. However, commonly-used stitching algorithms face difficulties in achieving effective alignment due to noise, artifacts and dense vasculature present in OCTA images. To address these challenges, we propose a novel retinal OCTA image stitching network, named -Net, which integrates multi-scale representation learning and dynamic location guidance. In the first stage, an image registration network with a progressive multi-resolution feature fusion is proposed to derive deep semantic information effectively. Additionally, we introduce a dynamic guidance strategy to locate the foveal avascular zone (FAZ) and constrain registration errors in overlapping vascular regions. In the second stage, an image fusion network based on multiple mask constraints and adjacent image aggregation (AIA) strategies is developed to further eliminate the artifacts in the overlapping areas of stitched images, thereby achieving precise vessel alignment. To validate the effectiveness of our method, we conduct a series of experiments on two delicately constructed datasets, i.e., OPTOVUE-OCTA and SVision-OCTA. Experimental results demonstrate that our method outperforms other image stitching methods and effectively generates high-quality wide-field OCTA images, achieving a structural similarity index (SSIM) score of 0.8264 and 0.8014 on the two datasets, respectively.

The Effect of Axial Length on Macular Vascular Density in Eyes with High Myopia

Objective

To evaluate the relationship between optical coherence tomography angiography (OCTA) findings and axial length (AL) in eyes with high myopia.

Materials and Methods

A total of 122 eyes from 78 patients were included. Seventy-five eyes with an AL ranging between 26.00 and 27.49 mm comprised Group 1, and 47 with an AL of ≥ 27.50 mm comprised Group 2. Spectral-domain OCT was performed to measure the central macular thickness, subfoveal choroidal thickness (SCT) and swept-source OCTA was utilized to obtain the data on foveal avascular zone (FAZ) and vascular density (VD) values at the superficial and deep capillary plexuses (SCP and DCP), outer retina (OuR), and choriocapillaris (CC) segments.

Results

While no significant differences were found in terms of the mean superficial-FAZ and deep-FAZ areas (p=0.284 and p=0.952, respectively), there were significant differences between the groups in terms of the mean foveal VD in the SCP (p=0.001), the mean total VD (p=0.045) and foveal VD in the DCP (p<0.001), the mean foveal VD (p=0.019) and superior parafoveal VD in the OuR (p=0.008), the mean total (p=0.005), temporal parafoveal (p=0.034), inferior parafoveal (p=0.029), and nasal parafoveal VDs in the CC segments (p=0.005).

Discussion

The findings of the present study highlight the complex interplay between axial elongation and retinal microvasculature, suggesting that factors beyond mechanical stretching may contribute to these alterations. The variability in the existing literature on this topic arises from inconsistencies in the definition of high myopia, the use of different OCTA devices, and heterogeneous study populations. By including eyes with myopic maculopathy and employing axial length-based classification, this study provides a broad representation of high myopia. However, its retrospective design, single-center setting, and monoracial cohort represent limitations. Future large-scale, prospective studies involving diverse populations are needed to elucidate further the pathophysiology of high myopia and its impact on retinal and choroidal microcirculation.

Conclusions

Our study revealed that high-myopic eyes with longer ALs exhibited increased total VD in the DCP and increased foveal VD in the SCP, DCP, and OuR segments, while they showed decreased total VD and temporal, inferior, and nasal parafoveal VDs in the CC segment compared to high-myopic eyes with shorter ALs.

VASCULAR CHANGES AND IRREVERSIBLE COMPLICATIONS IN 120° FUNDUS USING WIDEFIELD SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN VOGT-KOYANAGI-HARADA DISEASE

PURPOSE

To characterize the changes in fundus corresponding to 120° field of view in chronic Vogt-Koyanagi-Harada disease in the quiescent phase and explore the associations with irreversible complications in the fundus using widefield swept-source optical coherence tomography angiography.

METHODS

Prospective cross-sectional study. Sixty-nine patients with chronic Vogt-Koyanagi-Harada disease (115 eyes) and 55 healthy control subjects (110 eyes) were included and underwent widefield swept-source optical coherence tomography angiography. Univariate analyses of variations in retinal and choroidal vessel density (VD), choroidal volume, and choroidal vascularity index in patients with Vogt-Koyanagi-Harada with different disease durations and the control subjects were conducted. Logistic regression analysis was used to identify the associations with irreversible complications, including choroidal neovascularization, vasoproliferative tumor of the retina, and chorioretinal atrophy.

RESULTS

The Welch analysis of variance showed lower VD of superficial retina, deep retina, choriocapillaris, and large-sized and medium-sized vessels of the choroid, and choroidal volume and choroidal vascularity index in the patients with disease duration of >24 months compared with those with disease duration of ≤24 months (all P ≤ 0.011). The regression analysis revealed that the disease duration ( P = 0.008; OR = 1.02, 95% CI, 1.005-1.035) and VD of large-sized and medium-sized vessels of the choroid ( P = 0.001; OR = 0.707, 95% CI, 0.575-0.87) were significantly correlated with the irreversible complications.

CONCLUSION

Patients with chronic Vogt-Koyanagi-Harada in the quiescent phase with disease duration of >24 months exhibit more severe decreased VD in each layer of the retina and choroid, reduced choroidal volume, and sparse choroidal vascularity compared with those with disease duration ≤24 months. Prolonged duration and decreased VD of large-sized and medium-sized vessels of the choroid were associated with irreversible complications in the fundus.

Compartmental analysis of retinal vascular parameters and thickness in myopic eyes using SS-OCTA

Background

This study aimed to comprehensively explore the thickness and topographic distributions of retinal vessel alterations of different myopic eyes by using swept-source OCT angiography (SS-OCTA).

Methods

One hundred myopes were included in this observational cross-sectional study. All participants underwent a series of ocular examinations of biometrical parameters, including spherical equivalent refraction (SER), axial length (AL), intraocular pressure (IOP), curvature radius (CR), and others. Retinal parameters like vessel density (VD) of different compartments of papillary and peripapillary sectors were measured by SS-OCTA, respectively. Two sample-independent T-test was applied to identify intraocular differences in retinal biometrical indicators between groups, and correlation analysis was used to explore potential relationships between AL/CR ratio and some ocular variables.

Results

For high myopic participants, they exhibited a lower vessel density, a lower small vessel density, and a lower flow area, especially in the superficial layer and the nerve fiber layer (RNFL), along with a thinner superficial layer, RNFL and retina. More alterations were proved in nasal peripapillary sectors in high myopes. We also explored their hidden relationship with AL/CR ratio. We found that in non-high myopes, the thickness of the whole retina, RNFL and the superficial layer were all negatively correlated with AL/CR ratio in the papillary and peripapillary zone. In contrast, the vessel density and flow area of several vessel layers were positively correlated. However, there wasn't so much significance found in high myopic eyes.

Conclusion

Retinal vessel microstructure was more easily affected in highly myopic eyes, especially in superficial blood vessels, and compartmental analysis showed that alterations in nasal peripapillary sectors were more evident. Additionally, we highlighted hidden correlations between AL/CR ratio and blood flow characteristics of specific vascular layers, which could serve as sensitive biometrical indicators of early retinal damages.

Associations of quantitative contrast sensitivity with vascular metrics on widefield swept-source OCT angiography across stages of diabetic retinopathy

PURPOSE

To investigate structure-function associations between contrast sensitivity (CS) and widefield swept-source optical coherence tomography angiography (WF SS-OCTA) vascular metrics across stages of non-proliferative (NPDR) and proliferative diabetic retinopathy (PDR), without diabetic macular oedema.

METHODS

Prospective cross-sectional study in 140 eyes of 99 patients: 33 mild NPDR, 24 moderate/severe NPDR, 15 PDR, 33 diabetic without DR (DMnoDR) and 46 control eyes. Mixed-effects multivariable regression models to evaluate associations between quantitative contrast sensitivity function (Adaptive Sensory Technology) and vessel density (VD) and vessel skeletonised density (VSD) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) on same-day imaging with WF SS-OCTA (Plex Elite 9000, Carl Zeiss Meditec).

RESULTS

Standardised β coefficients for area under the logarithm of contrast sensitivity function curve (AULCSF) versus visual acuity (VA) at 3×3 mm scans: SCP VSD (β=0.32, p<0.001 vs -0.18, p=0.044), DCP VSD (β=0.30, p<0.001 vs -0.21, p=0.02), SCP VD (β=0.25, p=0.004 vs -0.13, p=0.129), DCP VD (β=0.26, p=0.003 vs -0.19, p=0.034). AULCSF was significantly reduced in mild NPDR (β=-0.28, p<0.001) and DMnoDR (β=-0.19, p=0.005) versus controls, while VA was not significantly different. AULCSF performed better than VA in differentiating between controls and DMnoDR (0.69 vs 0.50), controls and mild NPDR (0.76 vs 0.61) and controls and moderate/severe NPDR (0.89 vs 0.73).

CONCLUSIONS

DR-induced microvascular changes on OCTA are associated with larger changes on CS than in VA. CS is affected earlier than VA in the course of DR and performed better in discriminating between controls, DMnoDR and across DR stages.

Artificial intelligence-based prediction of neurocardiovascular risk score from retinal swept-source optical coherence tomography-angiography

The recent rise of artificial intelligence represents a revolutionary way of improving current medical practices, including cardiovascular (CV) assessment scores. Retinal vascular alterations may reflect systemic processes such as the presence of CV risk factors. The value of swept-source retinal optical coherence tomography-angiography (SS OCT-A) imaging is significantly enhanced by image analysis tools that provide rapid and accurate quantification of vascular features. We report on the interest of using machine-learning (ML) and deep-learning (DL) models for CV assessment from SS OCT-A microvasculature imaging. We assessed the accuracy of ML and DL algorithms in predicting the CHA2DS2-VASc neurocardiovascular score based on SS OCT-A retinal images of patients from the open-source RASTA dataset. The ML and DL models were trained on data from 491 patients. The ML models tested here achieved good performance with area under the curve (AUC) values ranging from 0.71 to 0.96. According to a classification into two neurocardiovascular risk groups, the EfficientNetV2-B3, a well suited DL model for retinal OCT-A images, predicted risk correctly in 68% of cases, with a mean absolute error (MAE) of approximately 0.697. Our models enable a confident prediction of the CHA2DS2-VASc score from SS OCT-A imaging, which could be a useful tool contributing to the assessment of neurocardiovascular profiles in the future.

Characteristics of optical coherence tomography in patients with iron deficiency anemia : a systematic review and meta-analysis

OBJECTIVE

The primary objective of this systematic review and meta-analysis was to assess the association between iron deficiency anemia (IDA) and retinal changes via optical coherence tomography (OCT).

METHODS

The search was conducted in MEDLINE, Scopus, Embase, Web of Science, and Google Scholar until February 1, 2024. Two independent researchers included the articles based on the inclusion and exclusion criteria. Data regarding the study design, patient characteristics, number of patients with and without IDA, mean and SD of the retinal nerve fiber layer (RNFL), C/D ratio, foveal avascular zone (FAZ) area and perimeter, foveal density and superficial and deep capillary plexus (SCP and DCP) vascular density (VD) were collected. STATA version 17.0 was used to compute pooled measures of the standardized mean difference. I2 and chi-square tests were used to assess heterogeneity between studies.

RESULTS

We found 1378 nonduplicate studies, 35 of which were potentially relevant. 19 articles met the inclusion criteria and were included in the review. The meta-analysis confirmed that there was a statistically significant association between IDA and RNFL thickness reduction (SMD = -0.76, 95% CI: -1.09 to -0.44 ; p-value = 0.001, I2 = 86.88%), FAZ area (SMD =-0.35, 95% CI: -0.67 to -0.02; p value = 0.04, I2 = 59.76%) and SCP VD (SMD = -1.12, 95% CI: -1.85 to -0.39; p-value = 0.001, I2 = 83.15%). The associations between IDA and the C/D ratio (SMD = 0.07, 95% CI: -0.13 to 0.28; p value = 0.49, I2 = 0.0%) and DCP VD (SMD = -0.30, 95% CI: -0.89 to 0.29; ,p-value = 0.32 ,I2 = 77.20%) were not significant. There was no considerable publication bias.

CONCLUSION

The results of this meta-analysis demonstrated that, compared with healthy controls, individuals with IDA presented a thinner RNFL, a smaller FAZ, and lower SCP and DCP vascular densities. However, further studies are needed to reach more conclusive results.

Optical coherence tomography angiography of the retina and choroid in systemic diseases

Optical coherence tomography angiography (OCTA) has transformed ocular vascular imaging, revealing microvascular changes linked to various systemic diseases. This review explores its applications in diabetes, hypertension, cardiovascular diseases, and neurodegenerative diseases. While OCTA provides a valuable window into the body's microvasculature, interpreting the findings can be complex. Additionally, challenges exist due to the relative non-specificity of its findings where changes observed in OCTA might not be unique to a specific disease, variations between OCTA machines, the lack of a standardized normative database for comparison, and potential image artifacts. Despite these limitations, OCTA holds immense potential for the future. The review highlights promising advancements like quantitative analysis of OCTA images, integration of artificial intelligence for faster and more accurate interpretation, and multi-modal imaging combining OCTA with other techniques for a more comprehensive characterization of the ocular vasculature. Furthermore, OCTA's potential future role in personalized medicine, enabling tailored treatment plans based on individual OCTA findings, community screening programs for early disease detection, and longitudinal studies tracking disease progression over time is also discussed. In conclusion, OCTA presents a significant opportunity to improve our understanding and management of systemic diseases. Addressing current limitations and pursuing these exciting future directions can solidify OCTA as an indispensable tool for diagnosis, monitoring disease progression, and potentially guiding treatment decisions across various systemic health conditions.

Segmentation of choroidal area in optical coherence tomography images using a transfer learning-based conventional neural network: a focus on diabetic retinopathy and a literature review

BACKGROUND

This study aimed to evaluate the effectiveness of DeepLabv3+with Squeeze-and-Excitation (DeepLabv3+SE) architectures for segmenting the choroid in optical coherence tomography (OCT) images of patients with diabetic retinopathy.

METHODS

A total of 300 B-scans were selected from 21 patients with mild to moderate diabetic retinopathy. Six DeepLabv3+SE variants, each utilizing a different pre-trained convolutional neural network (CNN) for feature extraction, were compared. Segmentation performance was assessed using the Jaccard index, Dice score (DSC), precision, recall, and F1-score. Binarization and Bland-Altman analysis were employed to evaluate the agreement between automated and manual measurements of choroidal area, luminal area (LA), and Choroidal Vascularity Index (CVI).

RESULTS

DeepLabv3+SE with EfficientNetB0 achieved the highest segmentation performance, with a Jaccard index of 95.47, DSC of 98.29, precision of 98.80, recall of 97.41, and F1-score of 98.10 on the validation set. Bland-Altman analysis indicated good agreement between automated and manual measurements of LA and CVI.

CONCLUSIONS

DeepLabv3+SE with EfficientNetB0 demonstrates promise for accurate choroid segmentation in OCT images. This approach offers a potential solution for automated CVI calculation in diabetic retinopathy patients. Further evaluation of the proposed method on a larger and more diverse dataset can strengthen its generalizability and clinical applicability.

Techniques for imaging the choroid and choroidal blood flow in vivo

The choroid, which is a highly vascularized layer between the retina and sclera, is essential for supplying oxygen and nutrients to the outer retina. Choroidal vascular dysfunction has been implicated in numerous ocular diseases, including age-related macular degeneration, central serous chorioretinopathy, polypoidal choroidal vasculopathy, and myopia. Traditionally, the in vivo assessment of choroidal blood flow relies on techniques such as laser Doppler flowmetry, laser speckle flowgraphy, pneumotonometry, laser interferometry, and ultrasonic color Doppler imaging. While the aforementioned methods have provided valuable insights into choroidal blood flow regulation, their clinical applications have been limited. Recent advancements in optical coherence tomography and optical coherence tomography angiography have expanded our understanding of the choroid, allowing detailed visualization of the larger choroidal vessels and choriocapillaris, respectively. This review provides an overview of the available techniques that can investigate the choroid and its blood flow in vivo. Future research should combine these techniques to comprehensively image the entire choroidal microcirculation and develop robust methods to quantify choroidal blood flow. The potential findings will provide a better picture of choroidal hemodynamics and its effect on ocular health and disease.

Artificial Intelligence-Assisted Perfusion Density as Biomarker for Screening Diabetic Nephropathy

Purpose

To identify a reliable biomarker for screening diabetic nephropathy (DN) using artificial intelligence (AI)-assisted ultra-widefield swept-source optical coherence tomography angiography (UWF SS-OCTA).

Methods

This study analyzed data from 169 patients (287 eyes) with type 2 diabetes mellitus (T2DM), resulting in 15,211 individual data points. These data points included basic demographic information, clinical data, and retinal and choroidal data obtained through UWF SS-OCTA for each eye. Statistical analysis, 10-fold cross-validation, and the random forest approach were employed for data processing.

Results

The degree of retinal microvascular damage in the diabetic retinopathy (DR) with the DN group was significantly greater than in the DR without DN group, as measured by SS-OCTA parameters. There were strong associations between perfusion density (PD) and DN diagnosis in both the T2DM population (r = -0.562 to -0.481, P < 0.001) and the DR population (r = -0.397 to -0.357, P < 0.001). The random forest model showed an average classification accuracy of 85.8442% for identifying DN patients based on perfusion density in the T2DM population and 82.5739% in the DR population.

Conclusions

Quantitative analysis of microvasculature reveals a correlation between DR and DN. UWF PD may serve as a significant and noninvasive biomarker for evaluating DN in patients through deep learning. AI-assisted SS-OCTA could be a rapid and reliable tool for screening DN.

Translational Relevance

We aim to study the pathological processes of DR and DN and determine the correspondence between their clinical and pathological manifestations to further clarify the potential of screening DN using AI-assisted UWF PD.

Asynchronous, semi-reverberant elastography

Optical coherence elastography measures elasticity-a property correlated with pathologies such as tumors due to fibrosis, atherosclerosis due to heterogeneous plaque composition, and ocular diseases such as keratoconus and glaucoma. Wave-based elastography, including reverberant elastography, leverages the properties of shear waves traveling through tissue primarily to infer shear modulus. These methods have already seen significant development over the past decade. However, existing implementations in OCT require robust synchronization of shear wave excitation with imaging, complicating widespread clinical adoption. We present a method for complete recovery of the harmonic shear wave field in an asynchronous, conventional frame-rate, raster-scanning OCT system by modeling raster-scanning as an amplitude modulation of the displacement field. This technique recovers the entire spatially and temporally coherent complex valued shear wave field from just two B-scans, while reducing the time scale for sensitivity to motion from minutes to tens of milliseconds. To the best of our knowledge, this work represents the first successful demonstration of reverberant elastography on a human subject in vivo with a conventional frame-rate, raster-scanning OCT system, greatly expanding opportunity for widespread translation.

Applications of optical coherence tomography angiography in glaucoma: current status and future directions

Glaucoma is a leading cause of irreversible blindness worldwide, with its pathophysiology remaining inadequately understood. Among the various proposed theories, the vascular theory, suggesting a crucial role of retinal vasculature deterioration in glaucoma onset and progression, has gained significant attention. Traditional imaging techniques, such as fundus fluorescein angiography, are limited by their invasive nature, time consumption, and qualitative output, which restrict their efficacy in detailed retinal vessel examination. Optical coherence tomography angiography (OCTA) emerges as a revolutionary imaging modality, offering non-invasive, detailed visualization of the retinal and optic nerve head microvasculature, thereby marking a significant advancement in glaucoma diagnostics and management. Since its introduction, OCTA has been extensively utilized for retinal vasculature imaging, underscoring its potential to enhance our understanding of glaucoma's pathophysiology, improving diagnosis, and monitoring disease progression. This review aims to summarize the current knowledge regarding the role of OCTA in glaucoma, particularly its potential applications in diagnosing, monitoring, and understanding the pathophysiology of the disease. Parameters pertinent to glaucoma will be elucidated to illustrate the utility of OCTA as a tool to guide glaucoma management.

Update on Clinical Trial Endpoints in Gene Therapy Trials for Inherited Retinal Diseases

Inherited retinal diseases (IRDs) encompass a wide spectrum of rare conditions characterized by diverse phenotypes associated with hundreds of genetic variations, often leading to progressive visual impairment and profound vision loss. Multiple natural history studies and clinical trials exploring gene therapy for various IRDs are ongoing. Outcomes for ophthalmic trials measure visual changes in three main categories-structural, functional, and patient-focused outcomes. Since IRDs may range from congenital with poor central vision from birth to affecting the peripheral retina initially and progressing insidiously with visual acuity affected late in the disease course, typical outcome measures such as central visual acuity and ocular coherence tomography (OCT) imaging of the macula may not provide adequate representation of therapeutic outcomes including alterations in disease course. Thus, alternative unique outcome measures are necessary to assess loss of peripheral vision, color vision, night vision, and contrast sensitivity in IRDs. These differences have complicated the assessment of clinical outcomes for IRD therapies, and the clinical trials for IRDs have had to design novel specialized endpoints to demonstrate treatment efficacy. As genetic engineering and gene therapy techniques continue to advance with growing investment from industry and accelerated approval tracks for orphan conditions, the clinical trials must continue to improve their assessments to demonstrate safety and efficacy of new gene therapies that aim to come to market. Here, we will provide an overview of the current gene therapy approaches, review various endpoints for measuring visual function, highlight those that are utilized in recent gene therapy trials, and provide an overview of stage 2 and 3 IRD trials through the second quarter of 2024.

ChoroidSeg-ViT: A Transformer Model for Choroid Layer Segmentation Based on a Mixed Attention Feature Enhancement Mechanism

Purpose

To develop a Vision Transformer (ViT) model based on the mixed attention feature enhancement mechanism, ChoroidSeg-ViT, for choroid layer segmentation in optical coherence tomography (OCT) images.

Methods

This study included a dataset of 100 OCT B-scans images. Ground truths were carefully labeled by experienced ophthalmologists. An end-to-end local-enhanced Transformer model, ChoroidSeg-ViT, was designed to segment the choroid layer by integrating the local enhanced feature extraction and semantic feature fusion paths. Standard segmentation metrics were selected to evaluate ChoroidSeg-ViT.

Results

Experimental results demonstrate that ChoroidSeg-ViT exhibited superior segmentation performance (mDice: 98.31, mIoU: 96.62, mAcc: 98.29) compared to other deep learning approaches, thus indicating the effectiveness and superiority of this proposed model for the choroid layer segmentation task. Furthermore, ablation and generalization experiments validated the reasonableness of the module design.

Conclusions

We developed a novel Transformer model to precisely and automatically segment the choroid layer and achieved the state-of-the-art performance.

Translational Relevance

ChoroidSeg-ViT could segment precise and smooth choroid layers and form the basis of an automatic choroid analysis system that would facilitate future choroidal research in ophthalmology.

Peripheral Superficial Retina Vascular Density and Area of Radial Peripapillary Capillaries Changes in Myopic Individuals: A Wide-Field OCT Angiography Study

Purpose

Using swept-source optical coherence tomography (SS-OCT) to explore the effect of high myopia on superficial retina vascular density (SVD) of the peripheral region and the area of radial peripapillary capillaries (RPCs).

Methods

In this cross-sectional study, a total of 91 volunteers (34 male subjects and 57 female subjects) were recruited and 34 individuals in the high myopic group (group A) and 57 individuals in the low myopic group (group B). Using the wide-field OCT-angiography (OCTA; 24 × 20 mm, 120 degrees angular field) compared the peripheral SVD and the area of RPC between the two groups and investigated its correlation with ocular axial length and diopter.

Results

Peripheral SVD of group B around the supratemporal (SVD1), supranasal (SVD2), infratemporal (SVD3), and infranasal (SVD4) directions were significantly higher than those of group A (all P < 0.05). The RPC area of group B around the supranasal (RPC2) and infranasal (RPC4) were significantly larger than that of group A (all P < 0.01). Ocular axial length and diopter were significantly correlated with SVD2 and SVD4 (all P < 0.05), and they also have a significant correlation with the supratemporal (RPC1), RPC2, and RPC4 (all P < 0.05).

Conclusions

Peripheral SVD was decreased and the RPC area was mainly reduced on the nasal side in the high myopic group. Peripheral SVD and area of RPC are significantly correlated with ocular axial length and diopter.

Translational Relevance

The wide-field OCTA can be used for new detection of myopia's impact on the retinal peripheral SVD and area of peripapillary RPC, offering new insights into the progression of myopia.

Retinal oximetry and microvascular assessment after hypertensive pregnancy complications

PURPOSE

Women with hypertensive disorders of pregnancy (HDP) are at increased risk of developing premature cardiovascular disease (CVD). The mechanisms behind this are not fully understood, but microvascular alterations have been documented in retinal arterioles and venules. The aim of this study was to use non-invasive retinal imaging to investigate the structural and functional properties of arterioles, venules and capillaries in this patient group.

METHODS

We examined 27 women with previous HDP and 23 controls at 3 years postpartum. The retinal microvasculature was assessed by vessel calibre measurements, retinal oximetry and optical coherence tomography angiography. Differences were analysed using non-parametric tests and multiple regression analyses, adjusted for age and body mass index.

RESULTS

Median arteriolar oxygen saturation (SaO2; 94.2% vs. 93.0%), venular oxygen saturation (SvO2; 60.1% vs. 62.4%) and arteriovenous saturation difference (AV-difference; 32.8% vs. 32.3%) were similar across groups. Capillary vessel density (VD; 46.2% vs. 46.3%), skeletonised VD (VSD; 21.3 vs. 21.1 mm/mm2) and vessel diameter index (21.65 vs. 21.86) were also comparable. In the HDP group, mean arterial pressure (MAP) was positively correlated with AV-difference (R2 = 0.209) and negatively correlated with arteriolar diameter (CRAE; r2 = 0.382).

CONCLUSIONS

Structural microvascular alterations appear not to be key biomarkers for CVD risk after HDP as early as 3 years postpartum in otherwise healthy women. Further studies are needed to evaluate whether such changes occur later in life. MAP was associated with AV-difference only in the HDP group, suggesting specific mechanisms affecting functional microvascular properties in these women.

HDB-Net: hierarchical dual-branch network for retinal layer segmentation in diseased OCT images

Optical coherence tomography (OCT) retinal layer segmentation is a critical procedure of the modern ophthalmic process, which can be used for diagnosis and treatment of diseases such as diabetic macular edema (DME) and multiple sclerosis (MS). Due to the difficulties of low OCT image quality, highly similar retinal interlayer morphology, and the uncertain presence, shape and size of lesions, the existing algorithms do not perform well. In this work, we design an HDB-Net network for retinal layer segmentation in diseased OCT images, which solves this problem by combining global and detailed features. First, the proposed network uses a Swin transformer and Res50 as a parallel backbone network, combined with the pyramid structure in UperNet, to extract global context and aggregate multi-scale information from images. Secondly, a feature aggregation module (FAM) is designed to extract global context information from the Swin transformer and local feature information from ResNet by introducing mixed attention mechanism. Finally, the boundary awareness and feature enhancement module (BA-FEM) is used to extract the retinal layer boundary information and topological order from the low-resolution features of the shallow layer. Our approach has been validated on two public datasets, and Dice scores were 87.61% and 92.44, respectively, both outperforming other state-of-the-art technologies.

Contrast Sensitivity Better Reflects Wide-Field Swept-Source Optical Coherence Tomography Angiography Vascular Metrics Among Healthy Eyes Compared to Visual Acuity

BACKGROUND AND OBJECTIVE

To evaluate the association between widefield swept-source optical coherence tomography angiography (WF SS-OCTA) and visual function in healthy eyes.

PATIENTS AND METHODS

Fifty-seven eyes of 45 patients were evaluated with visual acuity (VA), contrast sensitivity (CS), and WF SS-OCTA (3 × 3, 6 × 6, and 12 × 12 mm images) on the same day. Mixed-effects multivariable regression analyses were performed.

RESULTS

Contrast sensitivity metrics, including CS between 6 to 18 cycles per degree (cpd) and area under the logarithm CS function, were significantly associated with vessel density (VD) and vessel skeletonized density (VSD), whereas VA was not. The largest effect size was between CS at 18 cpd and VD (β = 0.41, P = 0.007) and VSD (β = 0.42, P = 0.006) on 12 × 12 mm images.

CONCLUSIONS

Reduced VSD and VD on WF SSOCTA was significantly associated with decreased CS, whereas VA was not. These results suggest CS could serve as a screening tool for early stage retinal and neurologic disorders. [Ophthalmic Surg Lasers Imaging Retina 2024;55:494-502.].