ULTRA-WIDEFIELD IMAGING DETECTION RATE IN IDENTIFYING PERIPHERAL RETINAL TEARS IN SINGLE VERSUS MONTAGE OF PERIPHERAL STEERING.

PURPOSE: To compare the detection rate of orthogonal, directed peripheral steering, and automontaged images with ultra-widefield imaging and the factors influencing the ability to identify retinal breaks. DESIGN: Retrospective cohort study. METHODS: Three hundred and seventy-six treatment-naive eyes (349 patients) that underwent laser retinopexy for retinal breaks between 2015 and 2021 were included. Pretreatment ultra-widefield orthogonal, peripheral steering, and automontage were cross-referenced to scleral-depressed examination to determine whether images successfully visualized all retinal breaks. Total relative retinal area (RRA) visualized was divided by its optic disk area (pixels) to calculate relative retinal area. Potential associations were assessed by linear regression analysis. RESULTS: One hundred and sixty two eyes (154 patients) met inclusion criteria. Orthogonal, peripheral steering, and automontage images showed detection rates of 47.5%, 90.7%, and 80.0%, respectively. Relative retinal area increased from orthogonal versus montage by 34.7% ± 26.5% (mean ± SD), which increased the detection rate by 90.8% ( P = 0.006). In linear probability models, vertical meridian tears decreased probability of identification in orthogonal, peripheral steering, and automontage by -26.6%, -86.2%, and -68.7%, respectively ( P < 0.001), and horizontal meridian tears increased the probability by 62.2%, 92.9%, and 85.5%, respectively, ( P < 0.001). Tears posterior to the equator in orthogonal images increased the probability (91.4%, P < 0.001). Artifacts such as lids/lashes, reflection, and face guard decreased the probability in directed peripheral steering by -28.6%, -50.0%, and -66.7%, respectively, ( P = 0.020, P = 0.049, and P = 0.016). CONCLUSION: Using directed peripheral steering and automontage increases RRA and detection rate of identifying peripheral retinal breaks. Tears in horizontal meridians or posterior to the equator increase the probability of identification. Common ultra-widefield imaging artifacts can significantly limit the probability of identifying retinal tears.

Ultrasound Assessment of Gaze-induced Posterior Eyewall Deformation in Highly Myopic Eyes.

Purpose: To establish a quantitative metric of posterior eyewall deformability in different directions of gaze in highly myopic eyes with and without posterior staphyloma. Methods: A prospective study was performed on 53 highly myopic patients (106 eyes). Ultrasound scans were acquired in primary, up, downward, nasal, and temporal gazes. A validated intensity-based segmentation algorithm was used to quantify the posterior eyewall geometry on digitalized B-scan images. Posterior eyewall local curvature (K) and distance (L) to the transducer were calculated. The associations between directions of gaze, axial length (AL), and presence of staphyloma with the K and L parameters were assessed. Results: A total of 53 participants (106 eyes) were studied. Multivariate regression analysis demonstrated that, after accounting for longer AL, and presence of staphyloma, eccentric gaze was often independently associated with various K and L parameters. Specifically, downward gaze was associated with increased posterior eyewall concavity as reflected in the maximum of K (KMax) (ß = 0.050, P < 0.001) and absolute value of KMax (ß = 0.041, P = 0.011). Both downward gaze and upgaze were independently associated with increase in the derivative of absolute KMax (which is consistent with more apparent, steeper staphyloma ridges), local KMax (which detects KMax at smaller intervals), and Kstd (which represents likelihood of staphyloma presence) and decrease in maximum of L (which represents movement of the staphyloma apex) with all P < 0.05. The ß coefficients for downward gaze were consistently greater in magnitude compared with those in upgaze. After accounting for AL and presence of staphyloma, horizontal gazes were independently associated only with decrease in the standard deviation of L (which also represents likelihood of staphyloma presence) and maximum of L. Conclusions: Downward gaze results in a significant increase in posterior eyewall concavity in highly myopic eyes after accounting for AL and staphyloma presence. In comparison with downward gaze, upgaze resulted in a lower magnitude, but significant changes in staphyloma ridge steepness and the likelihood of staphyloma presence. Horizontal gazes seemed to be associated with less posterior eyewall geometric parameters. Studies are required to further assess the association between downward gaze during near work on posterior eyewall concavity and possible effects on myopia development and progression.

Quadrant Asymmetry in Optical Coherence Tomography Angiography Metrics in Ischemic Versus Non-Ischemic Central Retinal Vein Occlusion Eyes.

Purpose: To determine whether quadrant asymmetry (QA) of optical coherence tomography angiography (OCTA) metrics differs between non-ischemic versus ischemic central retinal vein occlusion (CRVO). Methods: Fifty-eight eyes (21 non-ischemic, 10 ischemic CRVO, and 27 contralateral control eyes) underwent 3 × 3 mm spectral-domain OCTA scans with quantification of the superficial retinal layer vessel length density (VLD) and perfusion density (PD). QA, defined as the maximum-minus-minimum value among four parafoveal Early Treatment Diabetic Retinopathy Study (ETDRS) quadrants, was compared by linear regression including fixed effects for each eye. Results: Mean age was 73.6 ± 11.4 (range 39-88), 73.8 ± 12.4 (range 39-91) and 77.2 ± 9.83, (range 60-88); and QA was 3.46 ± 1.76, 3.14 ± 1.57, and 4.88 ± 2.42 for VLD and 0.072 ± 0.038, 0.062 ± 0.036, and 0.11 ± 0.056 for PD for control, non-ischemic, and ischemic, respectively. QA was significantly higher in ischemic (0.109 ± 0.056) than non-ischemic CRVO eyes (0.062 ± 0.036; P = 0.02) and control eyes for PD (0.072 ± 0.038; P = 0.03). QA was also greater in ischemic (4.875 ± 2.418) than non-ischemic CRVO (3.141 ± 1.572) for VLD (P = 0.04). In terms of identifying which particular quadrant is most affected by ischemia, multivariate regression analysis comparing intra-quadrant effect on the presence of ischemia versus non-ischemia showed no quadrant was significantly affected (P > 0.05 for all quadrants). Conclusions: Ischemic CRVO increases intraeye QA of OCTA metrics when compared to non-ischemic CRVO and control eyes. No specific ETDRS quadrant appears to be more affected. Translational Relevance: This work uses an intraeye method to delineate between ischemic and non-ischemic CRVO by OCTA imaging, overcoming inter-eye variables encountered in clinical care.

Quantitative assessment of the choroidal vasculature in myopic macular degeneration with optical coherence tomographic angiography.

Background: To assess and compare choroidal morphometric vascular parameters, using optical coherence tomographic angiography (OCTA), in highly myopic adults with and without myopic macular degeneration (MMD). Methods: This is a clinic-based observational study of 148 eyes with axial length (AL) ≥25mm, enrolled from the high myopia clinic of the Singapore National Eye Centre. MMD was graded from fundus photographs. Swept source OCT (SS-OCT) and OCTA were performed and assessed for choroidal layer thickness (CT) and choroidal vasculature (choroidal vessel density (CVD), choroidal branch area (CBA) and mean choroidal vessel width (MCVW)) in the different choroidal layers (overall choroidal layer (CL), medium-vessel choroidal layer (MVCL), large-vessel choroidal layer (LVCL)). Results: CTCL (r=-0.58, p<0.001), CTMVCL (r=-0.22, p=0.04), MCVWCL (r=-0.58, p<0.001), and CVDCL (r=-0.19, p=0.02) were negatively correlated with AL, while CBACL (r=0.61, p<0.001) was positively correlated. Compared to eyes with no MMD, eyes with MMD2 had lower CTCL (120.37±47.18µm vs 218.33±92.70µm, p<0.001), CTMVCL (70.57±15.28µm vs 85.32±23.71µm, p=0.04), CTLVCL (101.65±25.36µm vs 154.55±68.41µm, p=0.001) and greater CVDCL (71.10±3.97% vs 66.97±3.63%, p<0.001), CVDMVCL (66.96±2.35% vs 65.06±2.69%, p=0.002), CVDLVCL (68.36±2.56% vs 66.58±2.88%, p=0.012), MCVWMVCL (6.14±0.34µm vs 5.90±0.35µm, p=0.007), and CBACL (12.69±1.38% vs 11.34±1.18%, p<0.001). After adjusting for age, thicker CTCL (odds ratio (OR) 0.98, 95% confidence interval (CI) 0.97-0.99, p<0.001), CTMVCL (OR 0.97 (0.94-0.99), p=0.002) and CTLVCL (OR 0.97 (0.96-0.98, p<0.001) were significantly associated with lower odds of MMD2, while increased CVDCL (OR 1.37 (1.20-1.55), p<0.001), CVDMVCL (OR 1.39 (1.12-1.73), p=0.003), CVDLVCL (OR 1.31 (1.07-1.60), p=0.009), CBACL (OR 2.19 (1.55-3.08), p<0.001) and MCVWMVCL (OR 6.97 (1.59-30.51), p=0.01) was significantly associated with higher odds of MMD2. Conclusion: Decrease in choroidal vessel width, density and thickness, and an increase in vascular branching were observed in eyes with long AL. A thinner and denser choroid with greater branching area and vessel width, which may all be signs of hypoxia, were associated with greater odds of MMD2.

Correlation of Diabetic Disease Severity to Degree of Quadrant Asymmetry in En Face OCTA Metrics.

Purpose: To determine if diabetic retinopathy (DR) severity affects quadrant asymmetry (QA) of optical coherence tomography angiography (OCTA) metrics differentially. Methods: Ninety eyes (60 patients) with no diabetes mellitus (DM) (n = 39) or varying levels of DR (n = 51) had OCTA images (3 × 3 mm, Cirrus5000) acquired five times and averaged. The vessel length density (VLD) and perfusion density (PD) of the superficial retinal layer (SRL) and deep retinal layer (DRL) were measured. QA was defined as the maximum minus minimum value among four parafoveal Early Treatment Diabetic Retinopathy quadrants, and compared with DR severity by linear regression including fixed effects for each individual and eye. Results: The mean patient age was 55.5 years (range, 24-88 years) and 60% were male. Comparing severe nonproliferative DR or proliferative DR versus no DM/DR eyes, QA was significantly higher for SRL VLD, and PD (+0.67 ± 0.16 and +0.014 ± 0.003; P < 0.001) and DRL VLD, and PD (+1.25 ± 0.16 and +0.032 ± 0.003; P < 0.001). When comparing mild or moderate nonproliferative DR versus no DM/DR, the DRL VLD, and PD were significantly higher (+0.51 ± 0.13 and +0.015 ± 0.003; P < 0.001). For every step increase in DR severity, there was a +0.20 QA for SRL VLD, +0.004 SRL PD, +0.33 DRL VLD and +0.009 DRL PD (P < 0.001). Regression analysis comparing intraquadrant effect on DR severity demonstrated that the superior quadrant was most affected for all OCTA metrics. Conclusions: DR severity affects VLD and PD more asymmetrically across Early Treatment Diabetic Retinopathy quadrants with a linear increase in QA for each worsening level of DR. Individual intraeye metrics such as QA can accurately quantify DR severity without concerns for intereye variabilities that could affect the reproducibility and reliability of OCTA quantification.