UCLA

En Face Optical Coherence Tomography in Diagnosis of Persistent Subretinal Fluid & Outer Retinal Folds after Rhegmatogenous Retinal Detachment Repair

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Purpose To evaluate the role of en face optical coherence tomography (OCT) as a diagnostic tool for the detection of persistent subretinal fluid (PSRF) and outer retinal folds (ORF) following successful rhegmatogenous retinal detachment (RRD) repair. Design Observational post hoc analysis of two prospective surgical trials. Participants All patients with gradable (signal strength ≥ 5 and no segmentation error) 6x6 mm macular cube scans using spectral-domain OCT (SD-OCT) (Carl Zeiss Meditec, Jena, Germany) obtained between 1 and 2 months postoperatively were included in this study. Methods Scans were assessed for the presence or absence of PSRF or ORFs using en face OCT and cross-sectional B scans by two masked graders with any disagreements adjudicated by the third senior masked grader. Main Outcome Measure Sensitivity, specificity and predictive accuracy {using area under curve (AUC)} of en face OCT in comparison to cross-sectional OCT as the gold standard Results Two hu...

Tunable image-mapping optical coherence tomography

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Tunable image-mapping optical coherence tomography We present tunable image-mapping optical coherence tomography (TIM-OCT), which can provide optimized imaging performance for a given application by using a programmable phase-only spatial light modulator in a low-coherence full-field spectral-domain interferometer. The resultant system can provide either a high lateral resolution or a high axial resolution in a snapshot without moving parts. Alternatively, the system can achieve a high resolution along all dimensions through a multiple-shot acquisition. We evaluated TIM-OCT in imaging both standard targets and biological samples. Additionally, we demonstrated the integration of TIM-OCT with computational adaptive optics in correcting sample-induced optical aberrations.

Pregnancy associated hypertension screening with optical coherence tomography angiography

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Objective Hypertensive disorders are a common complication in pregnancy, occurring in 6-8% of U.S pregnancies, and often present with a prodrome of ocular manifestations. Optical Coherence Tomography Angiography (OCTA) is a technique for imaging the retina in cross section. As perfusion in the eye decreases, such as in hypertensive disorders, vessels increase in length in order to maintain perfusion in the area. We sought to identify if these subclinical ocular changes on OCTA could predict pregnancy associated hypertension (PAH). Study Design This is a retrospective cohort study of a prospective analysis of pregnant subjects undergoing OCTA after recruitment from a Fetal Diagnostic Unit at a large academic institution between February 2018 and December 2021. Study participants were in the third trimester with a singleton fetus and were categorized as healthy controls with no prior medical history or those who developed PAH. The PAH group was defined as those who developed gesta...

Reverse engineering for reconstructing baseline features of dry age-related macular degeneration in optical coherence tomography

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Age-related macular degeneration (AMD) is the most widespread cause of blindness and the identification of baseline AMD features or biomarkers is critical for early intervention. Optical coherence tomography (OCT) imaging produces a 3D volume consisting of cross sections of retinal tissue while fundus fluorescence (FAF) imaging produces a 2D mapping of retina. FAF has been a good standard for assessing dry AMD late-stage geographic atrophy (GA) while OCT has been used for assessing early AMD biomarkers beyond as well. However, previous approaches in large extent defined AMD features subjectively based on clinicians’ observation. Deep learning—an objective artificial intelligence approach, may enable to discover ’true’ salient AMD features. We develop a novel reverse engineering approach which bases on the backbone of a fully convolutional neural network to objectively identify and visualize AMD early biomarkers in OCT from baseline exams before significant atrophy occurs. Utilizing ...

The OCT angular sign of Henle fiber layer (HFL) hyperreflectivity (ASHH) and the pathoanatomy of the HFL in macular disease

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The Henle fiber layer (HFL) is comprised of bundles of unmyelinated photoreceptor axons intermingled with outer Müller cell processes. The photoreceptor axons extend from the cell bodies located in the outer nuclear layer and radially project toward the outer plexiform layer, the inner third of which includes the synaptic junctional complexes and the outer two-thirds of which includes the HFL. The oblique path of the HFL provides unique structural and reflectance properties and this radial anatomy is highlighted in many macular disorders including those with macular star exudation and HFL hemorrhage. Recent investigations using multimodal imaging techniques, especially cross sectional and en face optical coherence tomography (OCT), have provided new perspectives regarding HFL disruption in retinal diseases. The aim of this review is to highlight the pathoanatomy and multimodal imaging, especially OCT, associated with HFL disruption that is present in various macular diseases. A...

Overturning the mechanisms of cochlear amplification via area deformations of the organ of Corti

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The mammalian ear embeds a cellular amplifier that boosts sound-induced hydromechanical waves as they propagate along the cochlea. The operation of this amplifier is not fully understood and is difficult to disentangle experimentally. In the prevailing view, cochlear waves are amplified by the piezo-electric action of the outer hair cells (OHCs), whose cycle-by-cycle elongations and contractions inject power into the local motion of the basilar membrane (BM). Concomitant deformations of the opposing (or “top”) side of the organ of Corti are assumed to play a minor role and are generally neglected. However, analysis of intracochlear motions obtained using optical coherence tomography calls this prevailing view into question. In particular, the analysis suggests that (i) the net local power transfer from the OHCs to the BM is either negative or highly inefficient; and (ii) vibration of the top side of the organ of Corti plays a primary role in traveling-wave amplification....

Optical Coherence Tomography Biomarkers for Conversion to Exudative Neovascular Age-related Macular Degeneration

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Purpose To identify optical coherence tomography (OCT) biomarkers, including thin and thick double layer sign (DLS) for the progression from intermediate AMD (iAMD) to exudative macular neovascularization (MNV) over 24 months. Design Retrospective cohort study Methods Setting: Retina Consultants of Texas Patient Population 458 eyes of 458 subjects with iAMD in at least one eye with 24 months of follow-up data. Main Outcomes Measures The following biomarkers were assessed at baseline: high central drusen volume (≥0.03 mm 3 ), intraretinal hyperreflective foci (IHRF), subretinal drusenoid deposits, hyporeflective drusen cores, thick DLS, thin DLS, and central choroidal thickness. A binary logistic regression was computed to investigate the association between baseline OCT covariates and the conversion to exudative MNV within 24 months. In addition, fellow eye status was also included in the model. Results During follow-up, 18.1% (83/458) of eyes with iAMD progressed to exudative MN...

Optical Coherence Tomography Risk Factors for Development of Atrophy in Eyes with Intermediate Age-related Macular Degeneration

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Purpose To determine the frequency of multiple optical coherence tomography (OCT) biomarkers of intermediate age-related macular degeneration (iAMD) and their relationship with the development of complete retinal pigment epithelium and outer retinal atrophy (cRORA) after 2 years. Design Retrospective cohort study. Participants This retrospective analysis included 330 eyes of 330 consecutive patients with iAMD in at least one eye who had 24 months of follow-up data. Methods Spectralis OCT volumes scans (49 B-scans over 6x6mm, ART = 6, fovea-centered) at baseline were evaluated for previously described iAMD biomarkers including a high central drusen volume (DV; ≥0.03 mm 3 ), intraretinal hyperreflective foci (IHRF), subretinal drusenoid deposits (SDD), hypo-reflective drusen cores (hDC), and a thin or thick (multi-layered) double layer sign (DLS). The AMD status in the fellow eye was also assessed and classified as normal or early AMD, iAMD, exudative macular neovascularization (MN...

Insights into the developing fovea revealed by imaging

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Early development of the fovea has been documented by histological studies over the past few decades. However, structural distortion due to sample processing and the paucity of high-quality post-mortem tissue has limited the effectiveness of this approach. With the continuous progress in high-resolution non-invasive imaging technology, most notably optical coherence tomography (OCT) and OCT angiography (OCT-A), in vivo visualization of the developing retina has become possible. Combining the information from histologic studies with this novel imaging information has provided a more complete and accurate picture of retinal development, and in particular the developing fovea. Advances in neonatal care have increased the survival rate of extremely premature infants. However, with enhanced survival there has been an attendant increase in retinal developmental complications. Several key abnormalities, including a thickening of the inner retina at the foveal center, a shallower foveal pit...

A Metascore of Multiple Imaging Methods to Measure Long-Term Glaucoma Structural Progression

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Purpose : To develop a structural metascore (SMS) that combines measurements from different devices and expresses them on a single scale to facilitate their long-term analysis. Methods : Three structural measurements (Heidelberg Retina Tomograph II [HRT] rim area, HD-Cirrus optical coherence tomography [OCT] average retinal nerve fiber layer [RNFL] thickness, Spectralis OCT RNFL global thickness) were normalized on a scale of 0 to 100 and converted to a reference value. The resultant metascores were plotted against time. SMS performance was evaluated to predict future values (internal validation), and correlations between the average grades assigned by three clinicians were compared with the SMS slopes (external validation). Results : The linear regression fit with the variance approach, and adjustment to a Spectralis equivalent was the best-performing approach; this was denominated metascore. Plots were created for 3416 eyes of 1824 patients. The average baseline age (± stan...

Current and Future Advanced Imaging Modalities for the Diagnosis of Early Osteoarthritis of the Hip

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Hip osteoarthritis (OA) can be idiopathic or develop secondary to structural joint abnormalities of the hip joint (alteration of normal anatomy) and/or due to a systemic condition with joint involvement. Early osteoarthritic changes to the hip can be completely asymptomatic or may cause the development hip symptomatology without evidence of OA on radiographs. Delaying the progression of hip OA is critical due to the significant impact of this condition on the patient’s quality of life. Pre-OA of the hip is a newly established term that is often described as the development of signs and symptoms of degenerative hip disease but no radiographic evidence of OA. Advanced imaging methods can help to diagnose pre-OA of the hip in patients with hip pain and normal radiographs or aid in the surveillance of asymptomatic patients with an underlying hip diagnosis that is known to increase the risk of early OA of the hip. These methods include the delayed gadolinium-enhanced magnetic reson...

University of California at Los Angeles Received a 2022 NIH Grant for $567,451 for Intraocular Robotic Interventional and Surgical System for Automated Cataract Surgery

University of California at Los Angeles Received a 2022 NIH Grant for $567,451 for Intraocular Robotic Interventional and Surgical System for Automated Cataract Surgery. The principal investigator is Tsu-Chin Tsao. Below is a summary of the proposed work. The long-term goals of the present study are to improve surgical outcomes and reduce the risk of surgical complications of cataract surgery. It is our central hypothesis that intraoperative stabilization of the ocular structures, complete lens extraction, and accurate positioning of the intraocular lens implant through robotic manipulations and optical coherence tomography (OCT) feedback will significantly improve the safety of critical surgical steps in cataract surgery. Through improvements in visualization and tool control, we theorize that the risk of secondary cataracts, posterior capsule rupture, ametropia, and other surgical complications can be eliminated to improve safety and abate the costs associated with cataract surger...

Repeatability of new optical biometer and agreement with two validated optical biometers, all based on swept-source optical coherence tomography

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Purpose: to evaluate the repeatability of the measurements provided by a new optical biometer (EyeStar 900, Haag-Streit) based on swept-source optical coherence tomography (SS- OCT) and their agreement with the measurements given by two validated biometers based on the same technology, the IOLMaster 700 (Carl Zeiss Meditec) and Argos (Movu). Setting: IRCCS G.B. Bietti Foundation, Rome, Italy. Design: Prospective evaluation of diagnostic test. Methods: In a series of unoperated eyes, three consecutive scans were acquired with the EyeStar 900, and one with the IOLMaster 700 and the Argos. The following biometry parameters were analyzed: axial length (AL), keratometry (K), corneal astigmatism, central corneal thickness, corneal diameter (CD), anterior chamber depth (ACD), lens thickness (LT) and lens tilting. Repeatability was assessed using test-retest variability, the coefficient of variation (CoV), and the intraclass correlation coefficient (ICC); agreement was based on the 95% limi...

Age-related assessment of foveal avascular zone and surrounding capillary networks with swept source optical coherence tomography angiography in healthy eyes

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Aim To assess the macular capillary networks and foveal avascular zone (FAZ) with swept-source optical coherence tomography angiography in healthy eyes. Methods This cross-sectional, prospective, observational study enrolled 222 eyes of 116 healthy participants with no ocular or systemic disease. SS-OCTA images were captured using the PLEX Elite 9000 (Carl Zeiss Meditec Inc., Dublin, CA, USA) with a 6 × 6 mm pattern centered on the foveal center. Vessel length density (VLD), perfusion density (PD), and FAZ parameters were analyzed using the manufacturer’s automated software. Results A significant negative correlation was observed between age and average VLD in the superficial plexus, and average PD in both the superficial plexus and the whole retina. A significant positive correlation between age and foveal avascular zone perimeter and area was also noted. Age-wise comparisons showed a trend for an increase in VLD and PD until 40 years of age, with a...

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

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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...

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