Early Single-Examination Optical Coherence Tomography Biomarkers for Treatment-Requiring Retinopathy of Prematurity.

Purpose: Optical coherence tomography (OCT) is an emerging adjunct imaging modality to evaluate retinopathy of prematurity (ROP). From an 11-year research database, we identify early OCT biomarkers that predict treatment-requiring ROP (TR-ROP). Methods: For preterm infants with acceptable OCT images at 32 ± 1 weeks postmenstrual age (PMA), we extracted the following measures: total retina, inner retinal layer (IRL), and outer retinal layer (ORL) thicknesses at the fovea and the parafovea, inner nuclear layer (INL) and choroidal thickness, parafovea/fovea (P/F) ratio, and presence of macular edema. Using univariable and multivariable logistic regression models, we evaluated the association between retinal and choroidal OCT measurements at 32 ± 1 weeks PMA and development of TR-ROP. Results: Of 277 eyes (145 infants) with usable OCT images, 67 eyes had TR-ROP. Lower P/F ratio (P < 0.0001), thicker foveal IRL (P = 0.0001), and thinner choroid (P = 0.03) were associated with TR-ROP in univariable analysis, but lost significance of association when adjusted for gestational age and race. Absence of macular edema was associated with TR-ROP when adjusted for gestational age and race (P = 0.01). In 185 eyes without macular edema, P/F ratio was associated with TR-ROP in both univariable analysis (P < 0.0001) and multivariable analysis (P = 0.02) with adjustment for gestational age and race. Conclusions: Presence of macular edema at 32 ± 1 weeks PMA in infants with lower gestational age may be protective against TR-ROP. In infants without macular edema, P/F ratio may be an early OCT biomarker for development of TR-ROP. Incorporation of early OCT biomarkers may be useful in prediction of TR-ROP.

A pilot optical coherence tomography angiography classification of retinal neovascularization in retinopathy of prematurity.

Extraretinal neovascularization is a hallmark of treatment-requiring retinopathy of prematurity (ROP). Optical coherence tomography angiography (OCTA) offers vascular flow and depth information not available from indirect ophthalmoscopy and structural OCT, but OCTA is only commercially available as a tabletop device. In this study, we used an investigational handheld OCTA device to study the vascular flow in and around retinal neovascularization in seven preterm infants with treatment-requiring ROP and contrasted them to images of vascular flow in six infants of similar age without neovascular ROP. We showed stages of retinal neovascularization visible in preterm infants from 32 to 47 weeks postmenstrual age: Intraretinal neovascularization did not break through the internal limiting membrane; Subclinical neovascular buds arose from retinal vasculature with active flow through the internal limiting membrane; Flat neovascularization in aggressive ROP assumed a low-lying configuration compared to elevated extraretinal neovascular plaques; Regressed neovascularization following treatment exhibited decreased vascular flow within the preretinal tissue, but flow persisted in segments of retinal vessels elevated from their original intraretinal location. These findings enable a pilot classification of retinal neovascularization in eyes with ROP using OCTA, and may be helpful in detailed monitoring of disease progression, treatment response and predicting reactivation.

Longitudinal Choroidal Development in Preterm Infants.

Purpose: To characterize changes in subfoveal choroidal thickness in preterm infants from 30 to 60 weeks' postmenstrual age (PMA). Design: The prospective, observational Study of Eye Imaging in Preterm infantS (BabySTEPS) enrolled infants eligible for retinopathy of prematurity screening per the American Association of Pediatrics guidelines. Subjects: Infants imaged with an investigational, handheld OCT at ≥ 4 distinct imaging sessions between 30 to 60 weeks' PMA as part of BabySTEPS. Methods: Average choroidal thickness across the central subfoveal 1 mm in each eye at each time point was measured using custom segmentation software, and errors were manually corrected by a trained grader. We prospectively collected birth history data. A segmented mixed model was used to analyze the change in choroidal thickness as a function of PMA, birth weight, and gestational age (GA). Main Outcome Measures: Characterization of normative subfoveal choroidal thickness values and choroidal growth rate between 30 to 60 weeks' PMA. Results: We included 592 imaging sessions of 79 preterm infants (152 eyes). Mean (± standard deviation) GA was 27.5 ± 2.5 weeks. Mean choroidal thickness was 141.4 ± 34.5 µm at 30 weeks, 272.2 ± 83.9 µm at 38 weeks, and 306.2 ± 77.4 µm between 56 and 60 weeks. Between 30 and 60 weeks' PMA, choroidal growth followed a biphasic model, with a linear growth rate of 14.8 µm per week (95% confidence interval [CI], 13.6-16.0) from 30 until 38.4 weeks, then cessation of growth, with a growth rate of 0.3 µm per week (95% CI, -1.1 to 1.6) from 38.4 to 60 weeks. Infants with extremely low birth weight (ELBW; < 1000 g) and extremely preterm (GA < 28 weeks) infants had significantly slower initial growth rates compared with very low and low birth weight and very preterm and preterm infants (ELBW 13.0 vs. 21.0 µm per week; P < 0.0001 and extremely preterm 13.2 vs. 18.0 µm per week; P = 0.003). Conclusions: Preterm infant choroidal thickness experiences rapid linear growth from 30 to 38 weeks' PMA, at which time growth nearly stops. These foundational measurements and identification of the impact of extremes of low birth weight and prematurity on choroidal development will be essential as researchers begin to understand the role of choroidal development in ocular and retinal health in human infants. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Preterm infant retinal OCT markers of perinatal health and retinopathy of prematurity.

The increasing survival of preterm infants has led to the importance of improving long-term outcomes associated with preterm birth. Antenatal and perinatal insults not only impact mortality, but also long-term disability. While in the intensive care nursery, preterm infants are also exposed to various stressors that lead to long-term cognitive deficits. It is therefore critical to identify early, low-stress, non-invasive biomarkers for preterm infant health. Optical coherence tomography (OCT) is a powerful imaging modality that has recently been adapted to the infant population and provides noninvasive, high-resolution, cross-sectional imaging of the infant eye at the bedside with low stress relative to conventional examination. In this review we delve into discussing the associations between preterm systemic health factors and OCT-based retinal findings and their potential contribution to the development of non-invasive biomarkers for infant health and for retinopathy of prematurity (ROP).

Reducing the Impact of the COVID-19 Pandemic on Retinopathy of Prematurity Screening: Successful Strategies Learnt from a Multi-Center Tele-Medicine Program in India.

PURPOSE: Control of blindness due to retinopathy of prematurity (ROP) requires timely screening and treatment within 48-72 h. Anticipating that the coronavirus disease 2019 (COVID-19) pandemic would disrupt ROP services, we devised strategies ''on-the''-go"" to ameliorate this possiblity. We describe the successful outcomes of this approach in preventing infant blindness during the pandemic. METHODS: Data on the number of preemies recruited, screened and treated in the Karnataka Internet-assisted Diagnosis of Retinopathy of Prematurity (KIDROP) program were collected in a retrospective (2019, interval 1) - prospective (2020, interval 2) manner. We summarize 10 key strategies that were developed as we faced logistic, operational and implementation challenges. These included pragmatic methods of enhancing enrolment, transporting for screening and ensuring timely treatment in the outreach. RESULTS: The total number of ROP screening sessions was 20,598 (7,197 new) and 14,371 (5,773 new) during interval 1 and 2 respectively. Of these, 166 (2.3%) and 157 (2.7%) infants required treatment during interval 1 and 2 respectively. All infants needing treatment during the COVID period, were treated on time which was possible due to successful implementation of the 'on-the-go' strategies throughout the state of Karnataka. The fiscal equivalent of the blindness prevented during this period is USD 15.6 million. CONCLUSION: The greater decline in the number of ROP screening episodes in neonatal units in government hospitals was because several were converted to 'COVID only" hospitals. KIDROP's multi-zonal, decentralized strategy, which uses non-physician-based imaging in a telemedicine network, ensured that essential ROP services continued even during the lockdown.

Associations between systemic health and retinal nerve fibre layer thickness in preterm infants at 36 weeks postmenstrual age.

BACKGROUND/AIMS: Neonatal insults from systemic diseases have been implicated in the pathway of impaired neurodevelopment in preterm infants. We aimed to investigate the associations between systemic health factors and retinal nerve fibre layer (RNFL) thickness in preterm infants. METHODS: We prospectively enrolled infants and imaged both eyes at 36±1 weeks postmenstrual age (PMA) using a hand-held optical coherence tomography system at the bedside in the Duke intensive care nurseries. We evaluated associations between RNFL thickness and 29 systemic health factors using univariable and multivariable regression models. RESULTS: 83 infants with RNFL thickness measures were included in this study. Based on the multivariable model, RNFL thickness was positively associated with infant weight at imaging and was negatively associated with sepsis/necrotising enterocolitis (NEC). RNFL thickness was 10.4 µm (95% CI -15.9 to -4.9) lower in infants with than without sepsis/NEC in the univariable analysis (p<0.001). This difference remained statistically significant after adjustment for confounding variables in various combinations (birth weight, birthweight percentile, gestational age, infant weight at imaging and growth velocity). A 250 g increase in infant weight at imaging was associated with a 3.1 µm (95% CI 2.1 to 4.2) increase in RNFL thickness in the univariable analysis (p<0.001). CONCLUSIONS: Low infant weight and sepsis/NEC were independently associated with thinner RNFL in preterm infants at 36 weeks PMA. To our knowledge, this study is the first to suggest that sepsis/NEC may affect retinal neurodevelopment. Future longitudinal studies are needed to investigate this relationship further.

Biphasic change in retinal nerve fibre layer thickness from 30 to 60 weeks postmenstrual age in preterm infants.

BACKGROUND/AIMS: The optic nerve development during the critical postnatal weeks of preterm infants is unclear. We aimed to investigate the change of retinal nerve fibre layer (RNFL) in preterm infants. METHODS: We used an investigational handheld optical coherence tomography (OCT) system to serially image awake preterm infants between 30 and 60 weeks postmenstrual age (PMA) at the bedside. We assessed RNFL thickness in the papillomacular bundle and nasal macular ganglion cell layer+inner plexiform layer (GCL+IPL) thickness. We applied a segmented mixed model to analyse the change in the thickness of RNFL and GCL+IPL as a function of PMA. RESULTS: From 631 OCT imaging sessions of 101 infants (201 eyes), RNFL thickness followed a biphasic model between 30 and 60 weeks, with an estimated transition at 37.8 weeks PMA (95% CI: 37.0 to 38.6). RNFL thickness increased at 1.8 µm/week (95% CI: 1.6 to 2.1) before 37.8 weeks and decreased at -0.3 µm/week (95% CI: -0.5 to -0.2) afterwards. GCL+IPL thickness followed a similar biphasic model, in which the thickness increased at 2.9 µm/week (95% CI: 2.5 to 3.2) before 39.5 weeks PMA (95% CI: 38.8 to 40.1) and then decreased at -0.8 µm/week (95% CI: -0.9 to -0.6). CONCLUSION: We demonstrate the feasibility of monitoring RNFL and GCL+IPL thickness from OCT during the postnatal weeks of preterm infants. Thicknesses follow a biphasic model with a transition age at 37.8 and 39.5 weeks PMA, respectively. These findings may shed light on optic nerve development in preterm infants and assist future study designs.

Association Between Retinal Microanatomy in Preterm Infants and 9-Month Visual Acuity.

Importance: Preterm infants are at risk for poor visual acuity (VA) outcomes, even without retinal problems on ophthalmoscopy. Infant retinal microanatomy may provide insight as to potential causes. Objective: To evaluate the association between preterm infant retinal microanatomy and VA at 9 months' corrected age. Design, Setting, and Participants: This prospective observational study took place from November 2016 and December 2019 at a single academic medical center and included preterm infants enrolled in Study of Eye Imaging in Preterm Infants (BabySTEPS). Infants were eligible for enrollment in BabySTEPS if they met criteria for retinopathy of prematurity (ROP) screening, were 35 weeks' postmenstrual age or older at the time of first OCT imaging, and a parent or guardian provided written informed consent. Of 118 infants enrolled in BabySTEPS, 61 were included in this analysis. Data were analyzed from March to April 2021. Exposures: Bedside optical coherence tomography (OCT) imaging at a mean (SD) 39.85 (0.79) weeks' postmenstrual age and monocular grating VA measurement at 9 months' corrected age. Main Outcomes and Measures: Presence and severity of macular edema and presence of ellipsoid zone at the fovea measured by extracting semiautomated thicknesses of inner nuclear layer, inner retina, and total retina at the foveal center; choroid across foveal 1 mm; and retinal nerve fiber layer (RNFL) across the papillomacular bundle (PMB). Pearson correlation coefficients were calculated and 95% CIs were bootstrapped for the association between retinal layer thicknesses and continuous logMAR VA. Associations were analyzed between retinal microanatomy and normal (3.70 cycles/degree or greater) vs subnormal grating VA at 9 months' corrected age using logistic regression and with logMAR VA using linear regression, adjusting for birth weight, gestational age, and ROP severity at the time of OCT imaging and accounting for intereye correlation using generalized estimating equations. Results: The mean (SD; range) gestational age of included infants was 27.6 (2.8; 23.0-34.6) weeks, and mean (SD; range) birth weight was 958.2 (293.7; 480-1580) g. In 122 eyes of 61 infants, the correlations between retinal layer thicknesses and logMAR VA were as follows: r, 0.01 (95% CI, -0.07 to -0.27) for inner nuclear layer; r, 0.19 (95% CI, 0.01 to 0.35) for inner retina; r, 0.15 (95% CI, -0.02 to 0.31) for total retina; r, -0.22 (95% CI, -0.38 to -0.03) for choroid; and r, -0.27 (95% CI, -0.45 to 0.10) for RNFL across the PMB. In multivariable analysis, thinner RNFL across the PMB (regression coefficient, -0.05 per 10-µm increase in RNFL thickness; 95% CI, -0.10 to -0.01; P = .046) and prior ROP treatment (regression coefficient, 0.33 for ROP treatment; 95% CI, 0.11 to 0.56; P = .003) were independently associated with poorer 9-month logMAR VA. Conclusions and Relevance: In preterm infants, RNFL thinning across the PMB was associated with poorer 9-month VA, independent of birth weight, gestational age, need for ROP treatment, and macular microanatomy. Evaluation of RNFL thickness using OCT may help identify preterm infants at risk for poor vision outcomes.

Integrated Visualization Highlighting Retinal Changes in Retinopathy of Prematurity From 3-Dimensional Optical Coherence Tomography Data.

Importance: Early diagnosis of plus disease is critical in the management of retinopathy of prematurity (ROP). However, there is substantial interexpert disagreement in the diagnosis of plus disease based on vascular changes alone. Information derived from optical coherence tomography (OCT) may help characterize the severity of vascular and structural abnormalities in ROP. Objective: To describe integrated visualization of 3-dimensional (3-D) data from investigational swept-source OCT optimized to delineate retinal vascular and microanatomical features in eyes with and without ROP. Design, Setting, and Participants: This cross-sectional, observational report of OCT was captured in the prospective Study of Eye Imaging in Preterm Infants (BabySTEPS) designed in July 2016 at the Duke Health Intensive Care Nursery. Between December 2018 and August 2019, 2 preterm infants born at 24 and 30 weeks' gestation were enrolled, underwent ROP screening, and were imaged at those screening visits. Data at 36 weeks' postmenstrual age were analyzed via this visualization developed between September 2020 and May 2021. Main Outcomes and Measures: Superimposed en face retinal vascular shadow view (RVSV) montages and thickness maps were used along with OCT B-scans to evaluate retinal vasculature and cross-section in eyes with and without ROP. Results: In the right eyes of 2 infants, 3-D data were integrated and visualized from investigational bedside OCT imaging at the posterior pole. In the infant who developed type 1 ROP, RVSV-OCT confirmed presence of dilated and tortuous posterior pole vessels, shunting, and incomplete perifoveal vascular development, resulting in a temporal notch of avascular retina in zone 1. The thickness map revealed irregular pockets of thickening and thinning, and integrated visualization outlined the demarcation between thicker vascularized retina and thinner avascular fovea and presence of extraretinal neovascularization overlying elevated vessels in the superior arcades. In the infant without ROP (stage 0), RVSV-OCT revealed no abnormal vascular findings at the posterior pole. The integrated visualization showed a dome-shaped retinal thickening at the fovea, which was confirmed as macular edema. Conclusions and Relevance: In 2 preterm infants in BabySTEPS, 3-D visualization of OCT findings during the ongoing ROP disease process demonstrated supplemental information about the retinal vasculature and microanatomy that can be useful to clinicians. These additional details provided by OCT could be integrated into future ROP screening methods with artificial intelligence-based analytics.

Evaluating Contrast Sensitivity in Asian Indian Pre-Term Infants With and Without Retinopathy of Prematurity.

Purpose: The purpose of this study was to evaluate the contrast threshold in Asian Indian preterm infants with and without retinopathy of prematurity (ROP) using Newborn Contrast Cards measured during the first ROP screening and to correlate with final outcome and visual acuity at 3 months of corrected age. Methods: Preterm infants born ≤ 2000 grams birth weight (BW) and/or ≤ 34 weeks gestational age (GA) undergoing ROP screening were enrolled prospectively. Visual acuity was recorded using Teller Acuity Cards. Contrast threshold was measured with Newborn Contrast Cards at first screening visit and at the end of ROP screening at 40 weeks of postmenstrual age or older. Results: Of the 173 study infants, 134 (77.5%) did not have any stage of ROP. Of the remaining 39 (22.5%), 34 (87%) had type 2 ROP and 5 (13%) had type 1 ROP requiring treatment. The mean contrast threshold at the first visit of the no ROP type 1 and type 2 groups was 0.36 ± 0.07, 0.65 ± 0.19, and 0.46 ± 0.09, respectively (P < 0.001). Contrast threshold had a significant correlation with BW (R = -0.291, P = < 0.001) and gestational age (R = -0.47, P = < 0.001). The contrast threshold at the first visit correlated with visual acuity measured at 3 months of corrected age in logMAR (R = 0.36, P = 0.01). Other than BW and GA, no other systemic risk factors correlated with contrast threshold measured at the first screening visit. Conclusions: Newborn Contrast Cards are a viable tool to test contrast threshold in preterm infants. The association between contrast threshold and ROP, and its correlation with visual acuity, suggest that contrast threshold measurement may help predict the clinical vision outcome among prematurely born infants. Translational Relevance: Contrast threshold measurement may prove to be a useful tool in the estimation of visual potential in preterm infants.

Preterm Infant Stress During Handheld Optical Coherence Tomography vs Binocular Indirect Ophthalmoscopy Examination for Retinopathy of Prematurity.

IMPORTANCE: Binocular indirect ophthalmoscopy (BIO) examination for retinopathy of prematurity (ROP) is a well-known cause of repeated preterm infant stress. OBJECTIVE: To compare stress during investigational optical coherence tomography (OCT) imaging to that during BIO for ROP. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study examined infants at the bedside in the intensive care nursery. Consecutive preterm infants enrolled in Study of Eye Imaging in Preterm Infants (BabySTEPS) who had any research OCT imaging as part of the study. Patients were recruited from June to November 2019, and analysis began April 2020. MAIN OUTCOMES AND MEASURES: Infant stress was measured using modified components of a neonatal pain assessment tool before (baseline) and during OCT imaging and BIO examination of each eye. RESULTS: For 71 eye examinations of 16 infants (mean [SD] gestational age, 27 [3] weeks; birth weight, 869 [277] g), change from baseline to each eye examination was lower during OCT imaging than during BIO and the difference between OCT imaging and BIO at each eye examination was significant for the following: infant cry score (first eye examination: mean [SD], 0.03 [0.3] vs 1.68 [1.2]; -1.65 [95% CI, -1.91 to -1.39]; second eye examination: mean [SD], 0.1 [0.3] vs 1.97 [1.2]; -1.87 [95% CI, -2.19 to -1.54]), facial expression (first eye: 3 [4%] vs 59 [83%]; -79% [95% CI, -87% to -72%]; second eye: 4 [6%] vs 61 [88%]; -83% [95% CI, -89% to -76%]), and heart rate (first eye: mean [SD], -7 [16] vs 13 [18]; -20 [95% CI, -26 to -14]); second eye: mean [SD], -3 [18] vs 20 [20] beats per minute; -23 [95% CI, -29 to -18]) (P < .001 for all). Change in respiratory rate and oxygen saturation did not differ between OCT imaging and BIO. CONCLUSIONS AND RELEVANCE: While the role of OCT alone or in combination with BIO is currently unknown for ROP, these findings suggest that investigational OCT imaging of ROP is less stressful than BIO examination by a trained ophthalmologist.

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

Purpose: Children 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. Methods: Eyes 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. Results: Foveal 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. Conclusions: Foveation 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.

Optical coherence tomography angiography in preterm-born children with retinopathy of prematurity.

PURPOSE: To describe the foveal avascular zone (FAZ) and vessel density (VD) in the superficial and deep capillary plexus in children with a history of prematurity on optical coherence tomography angiography (OCTA) and their correlation with gestational age (GA) and birth weight (BW). METHODS: We enrolled 81 preterm- and eight term-born children in this prospective observational study. The Optovue RTVue AVANTI (Optovue Inc., Fremont, CA) was used to procure the OCTA images. The 3 × 3 mm scan protocol centered on the fovea and the central 1 mm of the grid along with the FAZ of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) was acquired. RESULTS: The mean SCP-VD was comparable between the preterms and term controls (p = 0.315) in the central fovea (1-mm grid). However, the SCP-VD of the 3-mm grid was lower in the preterms born without ROP, with type 1 ROP, and with type 2 ROP (47.61, 47.90, and 48.82 respectively) compared to that in the term group (51.38; p = 0.031). The FAZ in the SCP (p = 0.003) and DCP (p = 0.003) was significantly smaller in the preterms compared to that in the controls. Based on the GA sub-analysis, the FAZ was significantly smaller in the SCP and DCP of preterms born < 31 weeks and > 31 weeks GA (p < 0.000, p < 0.035, respectively). Based on the BW, the difference between the FAZ in the SCP (p = 0.002) and DCP (p = 0.003) was significant. There was no association between the visual acuity and FAZ. CONCLUSION: Optical coherence tomography angiography findings in this study show an altered foveal morphology and vascularity in preterms with and without ROP.

Macular OCT Characteristics at 36 Weeks' Postmenstrual Age in Infants Examined for Retinopathy of Prematurity.

PURPOSE: To report our ability to capture,-grade reliably, and analyze bedside macular OCT images from preterm infants and relate OCT findings to biological factors and retinopathy of prematurity (ROP) status at a single time window in the Study of Eye Imaging in Preterm Infants (BabySTEPS). DESIGN: Prospective, observational study. PARTICIPANTS: Preterm infants eligible for ROP screening with parental consent for research and a 36 ± 1 weeks' postmenstrual age (PMA) visit. METHODS: We imaged both eyes of preterm infants with an investigational noncontact, handheld swept-source (SS) OCT at the time of clinical ROP examinations. Macular OCT features and layer thicknesses for untreated eyes of infants at 36 ± 1 weeks' PMA were compared with demographic data and clinical ROP examination performed by experts. Statistical analyses accounted for the use of both eyes of infants. MAIN OUTCOME MEASURES: Macular OCT features and layer thicknesses, gender, race or ethnicity, gestational age, birth weight, ROP stage, and plus disease. RESULTS: We captured macular OCT from 169 eyes (1 eye excluded because of prior ROP treatment) at 36 ± 1 weeks' PMA. The quality of OCT volumes was excellent in 33 eyes (19%), acceptable in 112 eyes (67%), poor in 24 eyes (14%), and unusable in 0 eyes (0%). Macular edema was present in 60% of eyes and was bilateral in 82% of infants with edema. At the fovea, retinal and inner nuclear layer thickness increased with edema severity: 183 ± 36 µm and 51 ± 27 µm in mild (16% of eyes), 308 ± 57 µm and 163 ± 53 µm in moderate (25%), and 460 ± 76 µm and 280 ± 83 µm in severe edema (12%), respectively. With an increase in ROP stage from 0 to 2, the mean ± standard deviation retinal thickness at the fovea increased from 227± 124 µm to 297 ± 99 µm (P < 0.001). The choroid was thinner, 155 ± 72 µm, with preplus or plus disease versus without, 236 ± 79 µm (P = 0.04), whereas retinal thickness did not vary. CONCLUSIONS: We demonstrated the reliability of methods and the prevalence of OCT findings in preterm infants enrolled in BabySTEPS at a single time point of 36 ± 1 weeks' PMA. Variations in layer thicknesses in infants at this time point may reflect abnormalities resulting from delay in foveal development that may be impacted by macular edema, ROP, or both.

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

PURPOSE: To assess retinal nerve fiber layer (RNFL) thickness in preterm infants. DESIGN: Prospective observational study. METHODS: We imaged 83 awake infants (159 eyes) at 36 ± 1 weeks 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. RESULTS: RNFL was 3.4 µm 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 5.2 µm (95% confidence interval: 3.3-7.0) increase in RNFL thickness. Compared with very preterm infants, extremely preterm infants had thinner RNFL (58.0 ± 10.7 µm vs 63.4 ± 10.7 µm, P = .03), but the statistical significance disappeared after adjustment for birth weight (P = .25). RNFL thickness was 11.2 µm thinner in extremely low birth weight infants than in very low birth weight infants (55.5 ± 8.3 µm vs. 66.7 ± 10.2 µm; P < .001). The difference remained statistically significant after adjustment for gestational age. CONCLUSION: 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.

Systemic Factors Associated with a Thinner Choroid in Preterm Infants.

Purpose: To identify systemic health factors associated with a thinner choroid, which has been hypothesized as a cause of poor visual outcomes in low-birth weight infants. Design: The prospective, observational Study of Eye Imaging in Preterm Infants (BabySTEPS) enrolled infants recommended for retinopathy of prematurity screening based on the American Association of Pediatrics guidelines. Participants: Infants who underwent imaging with investigational handheld OCT at 36 ± 1 weeks' postmenstrual age (PMA) as part of BabySTEPS. Methods: Average choroidal thickness was measured across the central subfoveal 1 mm. We concurrently collected maternal and infant clinical health data. Univariate and multivariate linear regression analyses were performed to evaluate factors associated with choroidal thickness. The left and right eyes showed similar thicknesses, so their average was used for analysis. Main Outcomes Measures: Association between infant health factors and subfoveal choroidal thickness. Results: Subfoveal choroidal thickness was measurable in 82 of 85 infants and 94% of eyes. Mean choroidal thickness was 231 ± 78 µm. In the univariate analysis, a thinner choroid was associated with decreased growth velocity (P < 0.001), lower birth weight (P < 0.001), smaller head circumference (P < 0.001), younger gestational age (P = 0.01), the presence of patent ductus arteriosus (P = 0.05), sepsis or necrotizing enterocolitis (P = 0.03), bronchopulmonary dysplasia (P = 0.03), pulmonary interstitial emphysema (P = 0.002), more days on oxygen support (P < 0.001), and being on oxygen support at 36 weeks (P < 0.001) and at the time of imaging (P < 0.001). In the multivariate analysis, growth velocity (P = 0.002) and oxygen support at the time of OCT imaging (P = 0.004) remained associated with a thinner choroid. Conclusions: A thinner choroid is associated independently with growth velocity and receiving oxygen support at 36 ± 1 weeks PMA. This suggests that choroidal development in preterm infants may be related to growth rate in the first weeks of life and the prolonged use of supplemental oxygen. Longitudinal studies are needed to assess differences in choroidal thickness before 36 weeks PMA and to assess their impact on visual outcomes.

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

Purpose: To compare the repeatability and reproducibility of axial and lateral retinal measurements using handheld optical coherence tomography (OCT) systems and a tabletop OCT system. Methods: Graders 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 %). Results: Repeatability 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. Conclusions: All 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 Relevance: Our 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.

Morphological characteristics of early- versus late-onset macular edema in preterm infants.

Macular images of infants with early-onset edema (occurring at or before 33 weeks' postmenstrual age [PMA]) and infants with late-onset edema (at or after 36 weeks' PMA) were compared. At first appearance, early-onset edema has a more severe morphology, with foveal bulging and elongated cystoid spaces than late-onset edema, which presents as small cystoid spaces outside the foveal center. Morphological variations may be an indicator of the underlying cause of edema in preterm infants. The presence of mostly parafoveal small cystoid spaces in the late-onset edema group may be suggestive of an association with neurological injury.

Subclinical Retinal versus Brain Findings in Infants with Hypoxic Ischemic Encephalopathy.

PURPOSE: To detect retinal features and abnormalities on optical coherence tomography (OCT) without pupil dilation and relate these to brain injury in infants with a clinical diagnosis of hypoxic ischemic encephalopathy (HIE). METHODS: Under an institutional review board-approved protocol, we imaged eight infants without pharmacologic mydriasis, using handheld, non-contact spectral-domain (Leica Microsystems, IL) or investigational swept-source OCT at the bedside in an intensive care nursery, after birth (depending on primary clinical care team permission based on health status) and weekly until discharge. The newborn infant with HIE is neurologically unstable; therefore, pharmacologic mydriasis and stimulation with visible light for retinal examination are usually avoided. We analyzed images for retinal pathologies, central foveal thickness, and retinal nerve fiber layer (RNFL) thickness at the papillomacular bundle and compared them to historical controls and published normative data, HIE clinical assessment, and abnormalities on brain magnetic resonance imaging (MRI). RESULTS: On OCT, three of eight infants had bilateral multiple small macular and perimacular cystoid spaces; two of these three infants also had pronounced retinal ganglion cell layer thinning and severe brain injury on MRI and the third had bilateral paracentral acute middle maculopathy and mild brain injury on MRI. Other findings in HIE infant eyes included abnormally thin fovea and thin RNFL and markers of retinal immaturity such as the absence of sub-foveal photoreceptor development and sub-foveal fluid. CONCLUSIONS: Bedside handheld OCT imaging within the first 2 weeks of life revealed retinal injury in infants with HIE-related brain injury. Future studies may determine the relationship between acute/subacute retinal abnormalities and brain injury severity and neurodevelopmental outcomes in HIE.