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

USE OF HAND-HELD OPTICAL COHERENCE TOMOGRAPHY DURING RETINOPATHY OF PREMATURITY SCREENING DEMONSTRATES AN INCREASED OUTER RETINA FROM EARLY POSTMENSTRUAL AGE IN PRETERM INFANTS WITH RETINOPATHY OF PREMATURITY

PURPOSE

To identify structural markers of active retinopathy of prematurity (ROP) in foveal and parafoveal retinal layers using hand-held optical coherence tomography.

METHODS

Hand-held optical coherence tomography images (n = 278) were acquired from a prospective mixed cross-sectional longitudinal observational study of 87 participants (23-36 weeks gestational age; n = 30 with ROP, n = 57 without ROP) between 31 and 44 weeks postmenstrual age excluding treated ROP and features of cystoid macular edema. Six retinal layer thicknesses from the fovea to the parafovea were analyzed at five locations up to 1,000 µ m, temporally and nasally.

RESULTS

The mean outer retinal thickness during active ROP increased at the fovea and parafovea from postmenstrual age 33 weeks to 39 weeks ( P < 0.001), whereas the parafoveal inner nuclear layer and retinal nerve fiber layer reduced ( P < 0.001). Outer retinal thickness at the fovea from 33 weeks to 39 weeks postmenstrual age was consistently thicker in infants with ROP across all levels of prematurity (gestational age).

CONCLUSION

Increased foveal and parafoveal outer retina measured using hand-held optical coherence tomography shows potential as a marker for ROP screening.

Phenotypic Features Determining Visual Acuity in Albinism and the Role of Amblyogenic Factors

Albinism is a spectrum disorder causing foveal hypoplasia, nystagmus, and hypopigmentation of the iris and fundus along with other visual deficits, which can all impact vision. Albinism is also associated with amblyogenic factors which could affect monocular visual acuity. The foveal appearance in albinism can range from mild foveal hypoplasia to that which is indistinguishable from the peripheral retina. The appearance can be quickly and easily graded using the Leicester Grading System in the clinic. However, interquartile ranges of 0.3 logMAR for the grades associated with albinism limit the accuracy of the grading system in predicting vision. Here, we discuss the potential role of nystagmus presenting evidence that it may not be a major source of variability in the prediction of visual acuity. We also show that interocular differences in visual acuity are low in albinism despite high levels of amblyogenic factors indicating that active suppression of vision in one eye in albinism is uncommon.

Vitreoretinal biomarkers of retinopathy of prematurity using handheld optical coherence tomography: a review

Retinopathy of prematurity (ROP) is caused by abnormal retinal vascularization in premature infants that has the potential for severe long-term vision impairment. Recent advancements in handheld optical coherence tomography (OCT) have enabled noninvasive, high-resolution, cross-sectional imaging of the infant eye at the bedside. The use of handheld OCT devices in the diagnosis of ROP in premature infants has furthered our understanding of disease state and progression. This review discusses the known and novel biomarkers of ROP severity in premature infants identified through handheld OCT and potential for future directions.

Structural impact of arrested foveal development in children born extremely preterm without ROP at 6.5 years of age

Objectives

To characterize changes of foveal topography and microstructure of persisting foveal immaturity at 6.5 years of age in children born extremely preterm without retinopathy of prematurity (EPT-NoROP).

Methods

Images from previous optical coherence tomography examinations of 37 EPT-NoROP and 92 control eyes were selected from a regional cohort of the EXPRESS (Extremely Preterm Infants in Sweden) study. Thickness of ganglion cell + inner plexiform layer (GCL+), outer nuclear layer (ONL), retinal thickness (RT) at the foveal centre (FC), foveal depth (FD) and RT at the foveal rim were evaluated.

Results

Layer thickness of GCL+, ONL and RT was increased at FC in the EPT-NoROP group. More than two-thirds had thickness values above the control limit (control mean +2 SD) at FC (GCL + 68%, ONL 76%, and RT 68%), and 50% had reduced FD compared to controls. All parameters showed a high correlation within the EPT-NoROP group, whereas no or weaker correlation was seen in control eyes. The EPT-NoROP sub-groups, divided based on the control limit, did not differ in terms of associated factors such as gestational age, birth weight, visual acuity, and refraction.

Conclusions

Extreme prematurity without impact of ROP is associated with increased GCL + , ONL, and RT thickness at FC as well as reduced FD compared to full-term controls at age 6.5. This indicates that prematurity per se may have a profound effect on foveal anatomical maturation during the first months after birth. Our results suggest RT at FC to be a simple and useful measure of foveal anatomical immaturity.

RETINAL THICKNESS AND FOVEAL HYPOPLASIA IN ADULTS BORN PRETERM WITH AND WITHOUT RETINOPATHY OF PREMATURITY: The Gutenberg Prematurity Eye Study

PURPOSE

This study analyses whether prematurity, retinopathy of prematurity (ROP), and associated factors lead to altered foveal shape in adulthood and whether these alterations are associated with visual acuity.

METHODS

The Gutenberg Prematurity Eye Study is a German cohort study with a prospective ophthalmologic examination (participants aged 18-52 years) of individuals born preterm and full-term that were examined with spectral domain optical coherence tomography. Participants were grouped according to gestational age (GA) and postnatal ROP status. Multivariable linear regression analyses for foveolar retinal thickness, foveal hypoplasia, and posterior vitreous status were performed.

RESULTS

A total of 755 eyes of 414 preterm and full-term individuals were included (aged 28.6 ± 8.6 years, 233 female individuals). Central foveal retinal thickness increased as GA decreased. The prevalence of foveal hypoplasia was 2% (control group), 9% (GA 33-36), 18% (GA 29-32), 48% (GA ≤28), 50% (ROP without treatment), and 82% of eyes (with ROP requiring treatment). In multivariable analyses, central foveal thickness was independently associated with GA and advanced stages of ROP requiring treatment while foveal hypoplasia was only associated with GA. Posterior vitreous was more frequently visible as partially detached in full-term than in preterm individuals. Lower distant-corrected visual acuity correlated with increased foveolar thickness (rho = 0.08; P = 0.03) and with foveal hypoplasia (rho = 0.15, P < 0.001).

CONCLUSION

Our findings indicate that there are fetal origins affecting foveal shape, resulting in foveal hypoplasia potentially affecting the visual acuity in adulthood.

The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques

The field of ophthalmic imaging has grown substantially over the last years. Massive improvements in image processing and computer hardware have allowed the emergence of multiple imaging techniques of the eye that can transform patient care. The purpose of this review is to describe the most recent advances in eye imaging and explain how new technologies and imaging methods can be utilized in a clinical setting. The introduction of optical coherence tomography (OCT) was a revolution in eye imaging and has since become the standard of care for a plethora of conditions. Its most recent iterations, OCT angiography, and visible light OCT, as well as imaging modalities, such as fluorescent lifetime imaging ophthalmoscopy, would allow a more thorough evaluation of patients and provide additional information on disease processes. Toward that goal, the application of adaptive optics (AO) and full-field scanning to a variety of eye imaging techniques has further allowed the histologic study of single cells in the retina and anterior segment. Toward the goal of remote eye care and more accessible eye imaging, methods such as handheld OCT devices and imaging through smartphones, have emerged. Finally, incorporating artificial intelligence (AI) in eye images has the potential to become a new milestone for eye imaging while also contributing in social aspects of eye care.

Characterization of Foveal Development in Treatment-Naïve Extremely Preterm Infants

Objective

To characterize and quantify foveal development in treatment-naïve extremely preterm infants using optical coherence tomography.

Methods

In this cross-sectional study, eyes treated for retinopathy of prematurity before imaging were excluded. Inner retinal thickness and outer retina thickness at foveal center and foveal rim were assessed. Extremely preterm (EPT, <28 weeks gestational age) eyes were compared with infants more than 28 weeks of gestation using a multivariable dimension reduction analysis (principal component analysis) and a bilinear factor mode analysis (partial least square discriminant analysis) to determine group intervariability. Further analyses were performed to investigate the effects of gestation on foveal development.

Results

Twenty-six infants born at gestational ages ranging from 22 to 39 weeks were imaged between 32 and 80 weeks postmenstrual age. A principal component analysis and partial least squares discriminant analysis revealed that the foveal inner retina thickness was the main difference between EPT infants and non-EPT infants. This difference was reflected by comparing their inner retinal thickness over time (32-80 weeks postmenstrual age), which revealed a sustained thicker foveal inner retina for EPT infants when compared with non-EPT infants. The foveal pit seemed to be shallower in EPT infants when compared with non-EPT infants.

Conclusions

Twenty-eight weeks of gestation seems to be a critical timepoint for foveal development; EPT infants had altered foveal inner retinal development throughout early postnatal development, which led to a thicker foveal inner retina and a shallower foveal pit soon after birth.

Translational Relevance

Measuring untreated foveal parameters informs about the effects of prematurity on the fovea and provides a baseline when comparing with post-treatment foveal development.

Insights into the developing fovea revealed by imaging

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 smaller foveal avascular zone, and delayed development of the photoreceptors have been described in preterm infants when compared to full-term infants. Notably these abnormalities, which are consistent with a partial arrest of foveal development, appear to persist into later childhood and adulthood in these eyes of individuals born prematurely. Understanding normal foveal development is vital to interpreting these pathologic findings associated with prematurity. In this review, we first discuss the various advanced imaging technologies that have been adapted for imaging the infant eye. We then review the key events and steps in the development of the normal structure of the fovea and contrast structural features in normal and preterm retina from infancy to childhood. Finally, we discuss the development of the perifoveal retinal microvasculature and highlight future opportunities to expand our understanding of the developing fovea.

Recognition of intracranial hypertension using handheld optical coherence tomography in children (RIO Study): a diagnostic accuracy study protocol

INTRODUCTION

Paediatric intracranial hypertension (IH) is a rare but serious condition that can pose deleterious effects on the brain and vision. Estimating intracranial pressure (ICP) in children is difficult. Gold standard direct ICP measurement is invasive and carries risk. It is impractical to routinely perform direct ICP measurements over time for all children at risk of IH. This study proposes to assess the diagnostic accuracy of handheld optical coherence tomography (OCT), a non-invasive ocular imaging method, to detect IH in children.

METHODS AND ANALYSIS

This is a prospective study evaluating the diagnostic accuracy of handheld OCT for IH in at risk children. Inclusion criteria include clinical and/or genetic diagnosis of craniosynostosis, idiopathic intracranial hypertension, space occupying lesion or other conditions association with IH and age 0-18 years old. Exclusion criteria include patients older than 18 years of age and/or absence of condition placing the child at risk of IH. The primary outcome measures are handheld OCT and 48-hour ICP assessments, which will be used for diagnostic accuracy testing (sensitivity, specificity, positive predictive value, negative predictive value and accuracy). Main secondary outcome measures include visual acuity, fundoscopic examination, contrast sensitivity, visual field testing and visual evoked potentials, wherever possible.

ETHICS AND DISSEMINATION

Ethical approval was granted for this study by the East Midlands Nottingham 2 Research Ethics committee (UOL0348/IRAS 105137). Our findings will be disseminated through presentation at relevant meetings, peer-reviewed publication and via the popular media.

TRIAL REGISTRATION NUMBER

ISRCTN52858719.

Detection of intracranial hypertension in children using optical coherence tomography: a systematic review

OBJECTIVES

To evaluate the diagnostic capability of optical coherence tomography (OCT) in children aged under 18 years old with intracranial hypertension (IH).

DESIGN

Systematic review.

METHODS

We conducted a systematic review using the following platforms to search the keywords 'optical coherence tomography' and 'intracranial hypertension' from inception to 2 April 2020: Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, PubMed and Web of Science, without language restrictions. Our search returned 2729 records, screened by two independent screeners. Studies were graded according to the Oxford Centre for Evidence-Based Medicine and National Institutes of Health Quality Assessment Tool for observational studies.

RESULTS

Twenty-one studies were included. Conditions included craniosynostosis (n=354 patients), idiopathic IH (IIH; n=102), space-occupying lesion (SOL; n=42) and other pathology (n=29). OCT measures included optic nerve parameters, rim parameters (notably retinal nerve fibre layer thickness) and retinal parameters. Levels of evidence included 2b (n=13 studies), 3b (n=4) and 4 (n=4). Quality of 10 studies was fair and 11 poor. There was inconsistency in OCT parameters and reference measures studied, although OCT did demonstrate good diagnostic capability for IH in craniosynostosis, IIH and SOL.

CONCLUSIONS

This systematic review identified various studies involving OCT to assist diagnosis and management of IH in children with craniosynostosis, IIH, SOL and other pathology, in conjunction with established clinical measures of intracranial pressure. However, no level 1 evidence was identified. Validating prospective studies are, therefore, required to determine optimal OCT parameters in this role and to develop formal clinical guidelines.

PROSPERO REGISTRATION NUMBER

CRD42019154254.

Feasibility and Repeatability of Handheld Optical Coherence Tomography in Children With Craniosynostosis

Purpose

To determine whether handheld optical coherence tomography (OCT) is feasible and repeatable in children with craniosynostosis.

Methods

This was a prospective cross-sectional study. Children with syndromic and non-syndromic craniosynostosis 0 to 18 years of age were recruited between February 13, 2020, and October 1, 2020. Main outcome measures included feasibility (patient recruitment and handheld OCT success rates) and repeatability, which were assessed using intraclass correlation coefficients (ICCs) where repeated images of the optic nerve head (ONH) within the same visit were available. ONH parameters used for repeatability analysis included cup depth, width, and area; disc width; rim height; retinal thickness; retinal nerve fiber layer thickness; and Bruch's membrane opening minimum rim width.

Results

Fifty children were approached, and all 50 (100%) were successfully recruited. Median age was 51.1 months (range, 1.9-156.9; interquartile range, 37.0-74.2), and 33 of the children (66%) were male. At least one ONH image was obtained in 43 children (86%), and bilateral ONH imaging was successful in 38 children (76%). Factors boosting the likelihood of success included good understanding and cooperation of the child and parent/guardian and availability of an assistant. Repeatability analysis was performed in 20 children, demonstrating good repeatability (ICC range, 0.77-0.99; the majority exceeded 0.90). OCT correctly identified two cases of intracranial hypertension, one of which was undetected by prior fundoscopy.

Conclusions

Handheld OCT is feasible and repeatable in children with syndromic and non-syndromic forms of craniosynostosis.

Translational Relevance

Our handheld OCT approach could be used for the clinical surveillance of children with craniosynostosis.

Optical coherence tomography angiography in children with spontaneously regressed retinopathy of prematurity

PURPOSE

To assess optical coherence tomography angiography (OCTA) parameters in children born preterm who developed spontaneously regressed retinopathy of prematurity (sr-ROP, group 1), or had no ROP (PreT, group 2), compared with term-born age-matched controls (group 3).

METHODS

Cross-sectional comparative case series. Children aged 6-8 years had a complete ocular examination and OCT and OCTA imaging (Optovue RTVue AVANTI instrument). Foveal avascular zone (FAZ) area, FAZ perimetry, and vascular density in three slabs were measured automatically, and foveal depth was measured manually by two graders.

RESULTS

Groups 1, 2, and 3 (26, 32, and 34 eyes respectively) did not differ in age or gender, but differed in gestational age and birth weight. Both inner retinal thickness and foveal depth differed significantly between group 1 and 2, as did vascular density in the superficial and deep vascular plexus. VA, FAZ area, and perimetry were distinct in all three groups. VA correlated positively with FAZ area and foveal depth, negatively with vascular density.

CONCLUSION

OCTA parameters reveal microvascular changes that distinguish eyes with sr-ROP from premature eyes without ROP, as does visual acuity. It is not possible to infer if the cause is the presence of retinopathy or the different severity of retinal immaturity.

Effect of Prematurity on Foveal Development in Early School-Age Children

PURPOSE

To evaluate the foveal development in preterm children with optical coherence tomography and OCT angiography.

DESIGN

Retrospective cohort study.

METHODS

This study included children aged 6-8 years who were born prematurely and who did not receive retinopathy treatment. They were evaluated between September 2018 and July 2019, categorized according to gestational age (GA) (group I: GA ≤30 weeks; group II: GA between 31 and 34 weeks), and compared with full-term children (group III). Central foveal thickness (CFT), inner retinal thickness (IRT), outer retinal thickness (ORT), subfoveal choroidal thickness (CT), temporal and nasal CT, foveal avascular zone (FAZ) diameter, and vessel densities of superficial (SCP-VD) and deep capillary plexuses (DCP-VD) of the foveal and parafoveal areas were examined in detail.

RESULTS

The study included 126 eyes of 63 patients (group I: 40 eyes; group II: 46 eyes; and group III: 40 eyes). In group I, CFT, IRT, ORT, foveal SCP-VD, and foveal DCP-VD were significantly greater than those in the other groups, and temporal CT and FAZ diameter were significantly lower (P < .05). GA showed a significant negative correlation with CFT, IRT, ORT, foveal SCP-VD, and foveal DCP-VD and a significant positive correlation with subfoveal CT, temporal and nasal CT, and FAZ diameter (P < .05).

CONCLUSION

The morphological and vascular foveal structures in early school-age children who were born premature were different from those of full-term children. These differences were correlated with GA and more pronounced in those with GA of ≤30 weeks.

Auto-Processed Retinal Vessel Shadow View Images From Bedside Optical Coherence Tomography to Evaluate Plus Disease in Retinopathy of Prematurity

Purpose

To describe the creation of en face retinal vessel shadow view (RVSV) optical coherence tomography (OCT) images and assess the feasibility of using these for evaluating vascular disease in preterm infants at risk for retinopathy of prematurity (ROP).

Methods

In this exploratory study, we selected images from eyes with a range of ROP vascular disease, prospectively acquired from preterm infants using an investigational, noncontact, handheld, bedside swept-source OCT. We autosegmented OCT volumes using custom infant-specific software, extracted RVSV-OCT images from volumetric data bracketed around the retinal pigment epithelium, and automontaged the resulting RVSV-OCT images. Three masked ophthalmologists graded the RVSV-OCT montages as plus, pre-plus, or neither and ranked them by relative vascular disease severity.

Results

We selected images from 17 imaging sessions (7 plus, 4 pre-plus, 6 neither on clinical examination). On review, 15/17 (88%) RVSV-OCT montages were gradable for plus, pre-plus, or neither and all 17 montages were rankable for relative severity. Intergrader agreement for plus, pre-plus, or neither grading was good (κ, 0.67; 95% confidence interval, 0.42–0.86) and for relative severity ranking was excellent (intraclass correlation coefficient, 0.98; 95% confidence interval, 0.96–0.99).

Conclusions

Our novel automatic processing method can create RVSV-OCT montages optimized for retinal vessel visualization for ROP screening. Although our data support the feasibility of using RVSV-OCT montages for ranking relative vascular disease severity, there is room for improved OCT image capture and processing methods in preterm infants screened for ROP.

Translational Relevance

Creation and grading of RVSV-OCT images could eventually be integrated into an alternative method for ROP screening.

Detection of intracranial hypertension in children using optical coherence tomography: a systematic review protocol

INTRODUCTION

Intracranial hypertension (ICH) in children can have deleterious effects on the brain and vision. It is notoriously difficult to estimate intracranial pressure (ICP) in children and existing methods deliver suboptimal diagnostic accuracy to be used as screening tools. Optical coherence tomography (OCT) may represent a valuable, non-invasive surrogate measure of ICP, as has been demonstrated in a number of associated conditions affecting adults. More recently, OCT has been employed within the paediatric age group. However, the role of OCT in detecting ICH in children has not been rigorously assessed in a systematic review for all relevant conditions. Here, we propose a systematic review protocol to examine the role of OCT in the detection of ICH in children.

METHODS AND ANALYSIS

Electronic searches in the Cochrane Central Register of Controlled Trials, Medline, Embase, Web of Science and PubMed will identify studies featuring OCT in detecting ICH in children. Two independent screeners will identify studies for inclusion using a screening questionnaire. The systematic search and screening will take place between 2 April 2020 and 1 June 2020, while we aim to complete data analysis by 1 September 2020. Quality assessment will be performed using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. The primary outcome measure is the sensitivity and specificity of OCT in detecting ICH in children. Secondary outcomes measures include conditions associated with ICH per study, direct ICP monitoring, sensitivity and specificity of other measures for ICP and OCT parameters used.

ETHICS AND DISSEMINATION

Ethical approval is not required for the proposed systematic review as no primary data will be collected. The findings will be disseminated through presentations at scientific meetings and peer-reviewed journal publication.

PROSPERO REGISTRATION NUMBER

CRD42019154254.

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

Purpose

To 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.

Methods

A 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.

Results

Scanning 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).

Conclusions

We 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 Relevance

Our recommended protocol provides guidance on how pediatric optic nerve pathologies are managed by clinicians.