Handheld Optical Coherence Tomography Research Articles

Foveal Differentiation and Inner Retinal Displacement Are Arrested in Extremely Premature Infants.

PurposeChildren with a history of prematurity often have poorly developed foveae but when during development foveal differences arise. We hypothesize that the course of foveal development is altered from the time of preterm birth.MethodsEyes of 102 preterm infants undergoing retinopathy of prematurity screening examinations in the STudy of Eye imaging in Premature infantS (BabySTEPS) (NCT02887157) were serially imaged between 30 and 42 weeks postmenstrual age (PMA) using handheld optical coherence tomography systems. Total retinal thickness, inner retinal layer (IRL) thickness, and outer retinal layer (ORL) thickness were measured at the foveal center and parafovea. Foveal put depth, IRL thickness, and ORL thickness were compared between infants born at different gestational ages using mixed effects models.ResultsFoveal pit depth and IRL thickness were inversely related to gestational age; on average, the most premature infants had the thickest IRL and shallowest pits at all PMAs. Differences were evident by 30 weeks PMA and persisted through 42 weeks PMA. The foveal pits of the most premature infants did not progressively deepen, and the IRLs did not continue to thin with increasing chronological age.ConclusionsFoveation in extremely preterm infants is arrested from the earliest observed ages and fails to progress through term equivalent age. The developmental displacement of the IRL from the foveal center into the parafovea does not occur normally after preterm birth. These observations suggest that foveal hypoplasia seen in children with history of prematurity is due to disturbances in foveal development that manifest within weeks of birth.

Pediatric Vitreoretinal Surgery and Integrated Intraoperative Optical Coherence Tomography.

Intraoperative portable handheld and microscope-integrated OCT enhance the pediatric vitreoretinal surgeon's diagnostic abilities during examination under anesthesia and surgery, particularly in children who are challenging to examine preoperatively due to young age or ocular trauma. Improved OCT-guided visualization of vitreoretinal anatomic relationships has the potential to improve surgical safety and efficiency. In retinopathy of prematurity and other pediatric retinal vascular conditions, intraoperative OCT can be critical for distinguishing between retinoschisis and retinal detachment and highlighting abnormalities of the vitreoretinal interface that may contribute to development of tractional retinal detachments. During retinal detachment repair, intraoperative OCT aids identification of subtle retinal breaks, residual subretinal fluid, retained perfluorocarbon, preretinal membranes, and residual hyaloid, among other findings. In macular surgery, intraoperative OCT has demonstrated value in confirming completion or lack thereof of epiretinal and internal limiting membrane peeling and differentiating between lamellar and full-thickness macular holes. OCT-guided subretinal bleb formation and genetic vector delivery are critical to ensuring accurate localization of subretinal gene delivery for inherited retinal degenerations. Research on development of OCT-compatible surgical instruments, real-time three-dimensional volumetric OCT imaging, and integration with intraoperative OCT angiography are anticipated to further increase the utility of intraoperative OCT in pediatric vitreoretinal surgical decision-making.

Handheld optical coherence tomography for clinical assessment of dental plaque and gingiva.

.Significance: Optical coherence tomography (OCT) offers high spatial resolution and contrast for imaging intraoral structures, yet few studies have investigated its clinical feasibility for dental plaque and gingiva imaging in vivo. Furthermore, the accessibility is often limited to anterior teeth due to bulky imaging systems and probes.Aim: A custom-designed, handheld probe-based, spectral-domain OCT system with an interchangeable attachment was developed to assess dental plaque and gingival health in a clinical setting.Approach: Healthy volunteers and subjects with gingivitis and sufficient plaque were recruited. The handheld OCT system was operated by trained dental hygienists to acquire images of dental plaque and gingiva at various locations and after one-week use of oral hygiene products.Results: The handheld OCT can access premolars, first molars, and lingual sides of teeth to visualize the plaque distribution. OCT intensity-based texture analysis revealed lower intensity from selected sites in subjects with gingivitis. The distribution of the dental plaque after one-week use of the oral hygiene products was compared, showing the capability of OCT as a longitudinal tracking tool.Conclusions: OCT has a strong potential to display and assess dental plaque and gingiva in a clinical setting. Meanwhile, technological challenges remain to perform systematic longitudinal tracking and comparative analyses.

Repeatability and Reproducibility of Axial and Lateral Measurements on Handheld Optical Coherence Tomography Systems Compared with Tabletop System.

PurposeTo compare the repeatability and reproducibility of axial and lateral retinal measurements using handheld optical coherence tomography (OCT) systems and a tabletop OCT system.MethodsGraders measured central foveal thickness (CFT), optic nerve-to-fovea distance (OFD), and retinal nerve fiber layer (RNFL) thickness on OCT scans of the right eye of 10 healthy adults. Three OCT systems were used: handheld Leica Envisu, investigational handheld swept-source OCT (UC3), and Heidelberg Spectralis tabletop system. All eyes were imaged five times with each OCT system by each of two imagers. A components of variance analysis provided estimates of repeatability (variation due to random error) and reproducibility (variation due to imager, grader, and random error) expressed as standard deviation and (coefficient of variation %).ResultsRepeatability of CFT (µm) for Envisu, UC3, and Spectralis was 5.9 (2.6%), 6.9 (2.9%), and 4.7 (2.1%), and the reproducibility was 6.1 (2.7%), 7.3 (3.1%), and 4.7 (2.1%), respectively. The repeatability of OFD (mm) was 0.13 (2.9%), 0.10 (2.3%), and 0.07 (1.6%), and the reproducibility was 0.13 (3.0%), 0.10 (2.3%), and 0.07 (1.6%,) respectively. The repeatability for RNFL thickness (µm) for Envisu, UC3, and Spectralis was 4.3 (7.8%), 2.7 (5.4%), and 2.9 (4.9%), and the reproducibility was 4.5 (8.3%), 2.9 (5.8%), and 2.9 (4.9%), respectively.ConclusionsAll three OCT systems had good repeatability and reproducibility with coefficients of variation of less than 3.5% for CFT and OFD measurements, and less than 8.5% for RNFL thickness.Translational RelevanceOur findings inform the repeatability and reproducibility of retinal axial and lateral measurements on handheld OCT and are useful for both clinical research and patient care.

Birth Weight Is a Significant Predictor of Retinal Nerve Fiber Layer Thickness at 36 Weeks Postmenstrual Age in Preterm Infants

To assess retinal nerve fiber layer (RNFL) thickness in preterm infants. Prospective observational study. We imaged 83 awake infants (159 eyes) at 36 ± 1weeks postmenstrual age (defined as the time elapsed between the first day of the last maternal menstrual period and the time at imaging) using a handheld optical coherence tomography (OCT) system at the bedside. Blinded graders semi-automatically segmented RNFL in the papillomacular bundle (-15 to+15° relative to the fovea-optic nerve axis). We correlated RNFL thickness and 7 characteristics of interest (sex, race, ethnicity, gestational age, birth weight, stage of retinopathy at prematurity, and presence of pre-plus or plus disease) via univariable and multivariable regressions. RNFL was 3.4μm thicker in the right eyes than in the left eyes (P < .001). Among 7 characteristics, birth weight was the only independent predictor of RNFL thickness (P < .001). A 250-g increase in birth weight was associated with 5.2μm (95% confidence interval: 3.3-7.0) increase in RNFL thickness. Compared with very preterm infants, extremely preterm infants had thinner RNFL (58.0 ± 10.7μm vs 63.4 ± 10.7μm, P= .03), but the statistical significance disappeared after adjustment for birth weight (P= .25). RNFL thickness was 11.2μm thinner in extremely low birth weight infants than in very low birth weight infants (55.5 ± 8.3μm vs. 66.7 ± 10.2μm; P < .001). The difference remained statistically significant after adjustment for gestational age. Birth weight is a significant independent predictor of RNFL thickness near birth, implying that the retinal ganglion cells reserve is affected by intrauterine processes that affect birth weight.

Aphakic contact lens use for improved handheld optical coherence tomography imaging in pediatric aphakic patients

Handheld optical coherence tomography (OCT) makes it possible to acquire intraoperative and clinical imaging in infants and children for whom standard OCT is not possible. In patients with a retinal pathology who are left aphakic after surgery, however, image clarity is affected by insufficient refractive correction with handheld OCT. We describe a technique for supplementing the refractive power of the handheld OCT device with an aphakic contact lens to improve image clarity.

Reliability and Recommended Settings for Pediatric Circumpapillary Retinal Nerve Fiber Layer Imaging Using Hand-Held Optical Coherence Tomography.

PurposeTo investigate feasibility and reliability of 3-dimensional full circumpapillary retinal nerve fiber layer (cpRNFL) analysis in children, with and without glaucoma, without the use of sedation and to recommend a protocol for hand-held optical coherence tomography use.MethodsA cohort of pediatric glaucoma patients and normal children were imaged with hand-held optical coherence tomography to assess the feasibility of obtaining full cpRNFL. Two consecutive scans were acquired in a smaller sample to investigate test–retest repeatability and interassessor reproducibility. The cpRNFL thickness was assessed in four quadrants, at several visual angles from the optic nerve center.ResultsScanning was attempted in both eyes of 90 children with pediatric glaucoma and 180 controls to investigate feasibility (mean age, 6.98 ± 4.42 years). Scanning was not possible in 68 eyes of glaucoma children mainly owing to nystagmus, unclear optical media, or high refractive errors. Where three-dimensional imaging was possible, success at obtaining full cpRNFL was 67% in children with glaucoma and 89% for controls. Seventeen children with pediatric glaucoma and 34 controls contributed to reliability analysis (mean age, 6.3 ± 3.63 years). For repeatability intraclass correlation coefficients across quadrants ranged from 0.63 to 0.82 at 4° and improved to 0.88 to 0.94 at 6°. Intraclass correlation coefficients for reproducibility were also highest at 6° (>0.97 across all quadrants).ConclusionsWe demonstrate that acquisition and measurement of cpRNFL thickness values using 3-dimensional hand-held optical coherence tomography volumes in awake children is both feasible and reliable and is optimal at 6° from optic nerve center.Translational RelevanceOur recommended protocol provides guidance on how pediatric optic nerve pathologies are managed by clinicians.

Low-cost, ultracompact handheld optical coherence tomography probe for in vivo oral maxillofacial tissue imaging.

.Significance: Optical coherence tomography (OCT) has proven useful for detecting various oral maxillofacial abnormalities. To apply it to clinical applications including biopsy guidance and routine screening, a handheld imaging probe is indispensable. OCT probes reported for oral maxillofacial imaging were either based on a bulky galvanometric mirror pair (not compact or long enough) or a distal-end microelectromechanical systems (MEMS) scanner (raised safety concerns), or adapted from fiber-optic catheters (ill-suited for oral cavity geometry).Aim: To develop a handheld probe featuring great compactness and excellent maneuverability for oral maxillofacial tissue imaging.Approach: A dual-axis MEMS scanner was deployed at the proximal end of the probe and the scanned beam was relayed to the distal end through a 4f configuration. Such design provides both a perfect dual-axis telecentric scan and excellent compactness.Results: A handheld probe with a rigid part 70 mm in length and 7 mm in diameter and weighing 25 g in total was demonstrated through both ex vivo and in vivo experiments, including structural visualization of various oral maxillofacial tissues and monitoring the recovery process of an oral mucosa canker sore.Conclusions: The proposed probe exhibits excellent maneuverability and imaging performance showing great potential in clinical applications.

Vitreous Findings by Handheld Spectral-Domain OCT Correlate with Retinopathy of Prematurity Severity

To evaluate the association between retinopathy of prematurity (ROP) and vitreous findings in premature infants detected by handheld spectral-domain (SD) OCT. Prospective, observational cohort study. Consecutive sample of 92 premature infants requiring ROP screening at 2 academic neonatal intensive care units between July 2015 and March2018. Infants underwent handheld SD OCT at the time of routine ROP examinations. Two masked, trained graders analyzed right-eye vitreoretinal findings, including semiautomated quantification of punctate hyperreflective vitreous opacities within 5 foveal or parafoveal B-scans (vitreous opacity ratio). Excluding posttreatment data, vitreous findings were compared with clinical ROP diagnoses. Agreement between image graders for all vitreoretinal findings was 91% (κ= 0.86; 95% confidence interval, 0.82-0.90; P < 0.001). Among 92 infants undergoing 280 imaging sessions (52% male; mean gestational age, 28.3 ± 2.8 weeks; mean birthweight, 1014.5 ± 285.0 g), 36 of 92 (39%) demonstrated ROP. Punctate hyperreflective vitreous opacities were identified in 61 of 92 infants (66%). The presence of punctate hyperreflective vitreous opacities at least once was associated with a diagnosis of ROP (62% vs. 29% without opacities; P= 0.003), maximum ROP stage (P= 0.001), preplus or plus disease (24% vs. 5%; P= 0.005), and type 1 disease (14% vs. 2%; P= 0.03). Among 29 infants (45 imaging sessions) with right-eye punctate hyperreflective vitreous opacities, the vitreous opacity ratio from 2 graders (F1 score, 0.82 ± 0.36; Dice coefficient, 0.97 ± 0.04) correlated with ROP stage (P= 0.02). Tractional vitreous bands on imaging correlated with plus disease status (29% vs. 5% without bands; P= 0.05). Punctate hyperreflective vitreous opacities and tractional vitreous bands predict the presence and severity of ROP. Further studies should explore handheld OCT as a noninvasive ROP screening tool.

Optical Coherence Tomography (OCT) for the evaluation of internal adaptation of class V resin restorations on Dentin.

Internal adaptation of adhesive restorations affects their longevity. In a clinical setting, the dentists use visual and tactile examination to evaluate marginal adaptation, while radiographs provide somewhat reliable information about adaptation or secondary caries present. For class V restorations located on the vestibular (buccal) surfaces, none of the tools available can provide any information about the internal adaptation or the presence of secondary caries. OCT has been proven to be a useful tool for non-destructive assessment of internal adaptation of adhesive restorations. This paper is evaluating the use of a new high-resolution handheld OCT prototype with a pen-shaped intraoral tip and an imaging depth of 8mm to examine the internal adaptation and the presence of demineralization under resin restorations on the vestibular dentin surface. The Axsun OCT system helped evaluate the internal adaptation of composite restorations, differentiate between healthy and demineralised dentin, adhesive, and restoration layers. OCT provided a unique visualization and characterization of internal structures as well as non-contact assessment of marginal adaptation.

Reliability of Handheld Optical Coherence Tomography in Children Younger Than Three Years of Age Undergoing Vigabatrin Treatment for Childhood Epilepsy.

PurposeVigabatrin-associated retinal toxicity manifests as reduction in the clinical electroretinogram and retinal nerve fiber layer (RNFL) thinning. This observational investigation of RNFL thickness in young vigabatrin-treated children was to identify intravisit and intervisit reliabilities of peripapillary RNFL thickness measurements performed with Envisu (optical coherence tomography) OCT. Secondarily, a longitudinal assessment investigated the presence and extent of RNFL thinning.MethodsWe measured the handheld OCT in sedated children to evaluate the RNFL thickness using segmentation software. Intraclass correlation coefficient (ICC) statistics identified intravisit and intervisit reliabilities for RNFL thickness.ResultsTwenty-nine children (10.1 ± 6.0 months old) underwent handheld optical coherence tomography (OCT). Fourteen of these completed follow-up assessments. Intravisit reliability was good for the right eye (ICCs = 0.82−0.98) and the left eye (ICCs = 0.75−0.89) for each of the 4 retinal quadrants. Inter-visit ICCs for each of the 4 retinal quadrants were good (ICC = 0.82−0.98). There was no consistent change in RNFL thickness longitudinally.ConclusionsIn this pediatric cohort, RNFL thickness measures using handheld OCT provided good reliability within a single visit and between consecutive visits supporting its use as an adjunctive tool in the clinical setting. Further long-term follow-up is required to understand RNFL thickness changes in this specific population and its association with vigabatrin toxicity.Translational RelevanceThe findings of good reliability and clinical feasibility would provide an opportunity for the handheld OCT to monitor reliably for vigabatrin-associated retinal toxicity in children who often show noncompliance to traditional testing approaches.

Understanding the variability of handheld spectral-domain optical coherence tomography measurements in supine infants.

PurposeCentral foveal thickness (CFT) measurements from optical coherence tomography (OCT) scans provide a precise measure of severity of pathologic changes in the fovea, progress of disease and response to treatment. Although these measures are additionally valuable to assess foveal development in infants, their reproducibility is not known. The goal of this retrospective study is to evaluate the variation and reproducibility of CFT measurements using handheld spectral-domain OCT (hh-SDOCT) in supine infants compared to conventional adult tabletop imaging.MethodsImaging sessions with multiple macular, volume scans in one eye were selected for analysis from two participant groups: Group 1, 25 imaging sessions from 21 preterm infants without macular edema imaged supine in the nursery using hh-SDOCT (Leica/Bioptigen Envisu C2300, RTP, NC); Group 2, 25 imaging sessions from 25 adults imaged using tabletop Bioptigen SDOCT. For each imaging session, three macular OCT volumes with acceptable image quality were selected for analysis. CFTs were measured using a customized script for automatic segmentation. An expert grader and a typical grader corrected the segmentation lines for the central foveal frame. Coefficient of variations (CV) and intraclass correlation coefficients (ICC) were calculated for graders and systems and compared to the previous literature on OCT reproducibility.ResultsCFT measurements were repeatable and reproducible for both handheld and tabletop SDOCT systems. For handheld, grader ICC (CI) and mean CV were 0.94 (0.90–0.97) and 3.8 (typical) and 0.98 (0.96–0.99) and 2.9 (expert), and for tabletop were 0.91(0.83–0.96) and 2.1 (typical) and 0.92 (0.86–0.96) and 1.9 (expert). Intergrader reproducibility of handheld and tabletop SDOCT systems were ICC(CI) 0.97 (0.95–0.98) and 0.93 (0.89–0.96) respectively, and both are comparable to previously reported reproducibility of tabletop systems.ConclusionHandheld SDOCT is a reproducible instrument to measure foveal thicknesses in supine infants. It can be used in clinical research to evaluate foveal changes during retinal development and pathological conditions.

HANDHELD SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY FINDINGS OF X-LINKED RETINOSCHISIS IN EARLY CHILDHOOD.

Using handheld spectral domain optical coherence tomography (SDOCT) imaging to investigate in vivo microanatomic retinal changes and their progression over time in young children with juvenile X-linked retinoschisis (XLRS). This retrospective analysis was of handheld SD OCT images obtained under a prospective research protocol in children who had established XLRS diagnosis based on genetic testing or clinical history. Three OCT graders performed standardized qualitative and quantitative assessment of retinal volume scans, which were divided into foveal, parafoveal, and extrafoveal regions. Visual acuity data were obtained when possible. Spectral domain OCT images were available of both eyes in 8 pediatric patients with ages 7 months to 10 years. The schisis cavities involved inner nuclear layer in over 90% (15/16) of eyes in all 3 regions. Retinal nerve fiber and ganglion cell layer involvement was present only in the extrafoveal region in 63% (10/16) eyes and outer nuclear and plexiform layer in few others. In 7 children followed over 2 months to 15 months, the location of schisis remained consistent. Central foveal thickness decreased from the baseline to final available visit in 4/6 eyes. Ellipsoid zone disruption seemed to accompany lower visual acuity in 1/4 eyes. Early in life, the SD OCT findings in XLRS demonstrate differences in schisis location in fovea-parafoveal versus extrafoveal region, possible association between poor visual acuity and degree of ellipsoid zone disruption and decrease in central foveal thickness over time in this group. Furthermore, they illustrates that the pattern of XLRS in adults is already present in very young children, and unlike in older children and adults, those presenting with earlier disease may have a more aggressive course. Further studies in this early age group may provide more insights into treatment and prevention of progressive visual impairment in children with XLRS.

Can Structural Grading of Foveal Hypoplasia Predict Future Vision in Infantile Nystagmus?: A Longitudinal Study

PurposeTo evaluate structural grading and quantitative segmentation of foveal hypoplasia using handheld OCT, versus preferential looking (PL), as predictors of future vision in preverbal children with infantile nystagmus.DesignLongitudinal cohort study.ParticipantsForty-two patients with infantile nystagmus (19 with albinism, 17 with idiopathic infantile nystagmus, and 6 with achromatopsia) were examined.MethodsSpectral-domain handheld OCT was performed in preverbal children up to 36 months of age. Foveal tomograms were graded using our 6-point grading system for foveal hypoplasia and were segmented for quantitative analysis: photoreceptor length, outer segment (OS) length, and foveal developmental index (FDI; a ratio of inner layers versus total foveal thickness). Patients were followed up until they could perform chart visual acuity (VA) testing. Data were analyzed using linear mixed regression models. Visual acuity predicted by foveal grading was compared with prediction by PL, the current gold standard for visual assessment in infants and young children.Main Outcome MeasuresGrade of foveal hypoplasia, quantitative parameters (photoreceptor length, OS length, FDI), and PL VA were obtained in preverbal children for comparison with future chart VA outcomes.ResultsWe imaged 81 eyes from 42 patients with infantile nystagmus of mean age 19.8 months (range, 0.9–33.4 months; standard deviation [SD], 9.4 months) at the first handheld OCT scan. Mean follow-up was 44.1 months (range, 18.4–63.2 months; SD, 12.0 months). Structural grading was the strongest predictor of future VA (grading: r = 0.80, F = 67.49, P < 0.0001) compared with quantitative measures (FDI: r = 0.74, F = 28.81, P < 0.001; OS length: r = 0.65; F = 7.94, P < 0.008; photoreceptor length: r = 0.65; F = 7.94, P < 0.008). Preferential looking was inferior to VA prediction by foveal grading (PL: r = 0.42, F = 3.12, P < 0.03).ConclusionsHandheld OCT can predict future VA in infantile nystagmus. Structural grading is a better predictor of future VA than quantitative segmentation and PL testing. Predicting future vision may avert parental anxiety and may optimize childhood development.

Electrically tunable lens integrated with optical coherence tomography angiography for cerebral blood flow imaging in deep cortical layers in mice.

We report the use of an electrically tunable lens (ETL) in a 1.3μm spectral-domain optical coherence tomography (SD-OCT) system to overcome the depth of focus (DOF) limitation in conventional OCT systems for OCT angiography (OCTA) in a mouse cerebral cortex. The ETL provides fast and dynamic control of the axial focus of the probe beam along the entire range of the mouse cortex, upon which we performed cerebral blood flow imaging of all cortical layers by stitching the OCTA images automatically captured at six focal depths. Capillary vasculature and axial blood flow velocity were revealed in distinctive cortical layers and, for the first time, to the best of our knowledge, in white matter. The results have shown the system capability to conveniently investigate the hemodynamics in deep cortical layers in the mouse brain. More importantly, the compact integration of an ETL will benefit the future design of handheld or intra-cavity OCT probes for a wide range of applications in research and clinical fields.

Secondary Prevention of Retinoblastoma Revisited: Laser Photocoagulation of Invisible New Retinoblastoma

Invisible retinoblastoma tumors are now detected with screening for retinal tumors in at-risk neonates (those inheriting RB1 pathogenic alleles from affected parents) using handheld OCT. Laser photocoagulation is challenging, requiring exact localization of a tumor invisible to indirect ophthalmoscopy and standard imaging. We describe OCT-guided localization and photocoagulation of these invisible tumors with 1-year follow-up. Retrospective, noncomparative, single-institutional, observational case series. Children with any clinically invisible retinoblastoma tumor that was detected on OCT posterior pole screening. OCT revealed round homogeneous invisible tumors within the inner nuclear layer. Software calipers placed beside anatomic retinal landmarks (branched/curved vessels, fovea, or optic disc) mapped the tumor location and extent. A single laser (532 nm) burn flagged the location, and OCT evaluated the tumor-laser burn relationship; laser treatment was then continued in the correct location. Post-laser OCT ensured complete treatment. Accuracy (frequency of geographic miss and skip areas), effectiveness (recurrence rate), and burden (scar size and characteristics at final follow-up) of laser treatment. Eleven new invisible posterior pole tumors in 7 eyes of 5 children were treated by this technique. Localization and tumor-laser burn relationships were accurate in 11 of 11 tumors (100%, 95% confidence interval [CI], 49.9-100), and all showed swelling and hyper-reflectiveness of the tumor in post-laser OCT. Two photocoagulation sessions (2 weeks apart) were sufficient to successfully manage 9 of 11 tumors (82%, 95% CI, 37.4-100) with resulting permanent flat scars. One tumor (9%, 95% CI, 0.2-50.6) developed OCT-detected subclinical recurrences within 3 months, treated by 1 laser session. No treatment scar showed gliosis, foveal involvement, or retinal traction at 1-year follow-up. Scar expansion occurred in 1 tumor (9%, 95% CI, 0.2-50.6), and all scars (100%, 95% CI, 49.9-100) showed pigmentary changes. The OCT-guided localization and photocoagulation technique is valuable in achieving precision results in managing invisible new retinoblastoma tumors. This technique shows a potential to improve outcomes of secondary prevention screening for retinoblastoma.

POTENTIAL UTILITY OF FOVEAL MORPHOLOGY IN PRETERM INFANTS MEASURED USING HAND-HELD OPTICAL COHERENCE TOMOGRAPHY IN RETINOPATHY OF PREMATURITY SCREENING.

To investigate dynamic foveal morphology with postmenstrual age, in preterm infants with and without retinopathy of prematurity using hand-held optical coherence tomography, adjusting for gestational age (GA) and birthweight (BW). Prospective mixed cross-sectional/longitudinal observational study of 87 participants (23-36 weeks GA; n = 30 with, n = 57 without retinopathy of prematurity) using hand-held optical coherence tomography images (n = 278) acquired between 31 weeks and 44 weeks postmenstrual age excluding treated retinopathy of prematurity. Measurements included foveal width, area, depth, central foveal thickness, maximum slope, and parafoveal retinal thickness at 1,000 µm nasal and temporal to the central fovea. Retinopathy of prematurity was significantly correlated with only foveal width in either GA or BW adjusted statistical models. In contrast, severity of prematurity (GA, BW) correlated with foveal area (P < 0.005), depth (P ≤ 0.001), and slope (P < 0.01), although central foveal thickness (P = 0.007) and parafoveal retinal thickness (P < 0.001) correlated with GA, but not with BW. Foveal width is independent of GA and BW with potential in retinopathy of prematurity screening assessment using hand-held optical coherence tomography. Foveal morphology could be graded in prematurity during development, with possible implications for future management of preterm infants.

Handheld spectrally encoded coherence tomography and reflectometry for motion-corrected ophthalmic optical coherence tomography and optical coherence tomography angiography.

.Optical coherence tomography (OCT) is the gold standard for quantitative ophthalmic imaging. The majority of commercial and research systems require patients to fixate and be imaged in a seated upright position, which limits the ability to perform ophthalmic imaging in bedridden or pediatric patients. Handheld OCT devices overcome this limitation, but image quality often suffers due to a lack of real-time aiming and patient eye and photographer motion. We describe a handheld spectrally encoded coherence tomography and reflectometry (SECTR) system that enables simultaneous en face reflectance and cross-sectional OCT imaging. The handheld probe utilizes a custom double-pass scan lens for fully telecentric OCT scanning with a compact optomechanical design and a rapid-prototyped enclosure to reduce the overall system size and weight. We also introduce a variable velocity scan waveform that allows for simultaneous acquisition of densely sampled OCT angiography (OCTA) volumes and widefield reflectance images, which enables high-resolution vascular imaging with precision motion-tracking for volumetric motion correction and multivolumetric mosaicking. Finally, we demonstrate in vivo human retinal OCT and OCT angiography (OCTA) imaging using handheld SECTR on a healthy volunteer. Clinical translation of handheld SECTR will allow for high-speed, motion-corrected widefield OCT and OCTA imaging in bedridden and pediatric patients who may benefit ophthalmic disease diagnosis and monitoring.

Handheld Optical Coherence Tomography Normative Inner Retinal Layer Measurements for Children

Measurements of the ganglion cell complex (GCC), comprising the retinal nerve fiber (RNFL), ganglion cell, and inner plexiform layers, can be correlated with vision loss caused by optic nerve disease. Handheld optical coherence tomography (HH-OCT) can be used with sedation in children who are not amenable to traditional imaging. We report GCC and RNFL measurements in normal children using HH-OCT. Prospective observational study of normal children ≤5 years of age. Healthy, full-term children ≤5 years of age undergoing sedation or anesthesia were enrolled. Exclusion criteria included prematurity and pre-existing neurologic, genetic, metabolic, or intraocular pathology. Demographic data, axial length (Master-Vu Sonomed Escalon, Lake Success, New York, USA), and HH-OCT macular and optic nerve volume scans at 0° (Bioptigen, Inc., Morrisville, North Carolina, USA) were obtained. Retinal segmentation was completed with DOCTRAP software, creating average volume thickness maps. Sixty-seven children (67 eyes, 31 males ranging in age from 3.4-70.9months) were enrolled. Average axial length was 21.2 ± 1.0mm with mean spherical equivalent+1.49 ± 1.34 diopters (range-2.25 to 4.25). Average GCC volume for the total retina was 0.28 ± 0.04mm3. Forty-seven of these eyes had RNFL analysis. Average RNFL thickness of the papillomacular bundle was 38.2 ± 9.5μm. There was no correlation between GCC volume, RNFL thickness, patient age, or axial length. Average GCC volume and RNFL thickness was stable from 6months to 5 years of age. This study provides normative data for GCC and RNFL obtained by HH-OCT in healthy eyes of young children, to serve in evaluating those with optic neuropathies.

Detection and characterisation of optic nerve and retinal changes in primary congenital glaucoma using hand-held optical coherence tomography

ObjectiveTo investigate (1) the feasibility of scanning the optic nerve (ON) and central retina with hand-held optical coherence tomography (HH-OCT) without sedation or anaesthesia in primary congenital glaucoma (PCG), (2)...