Axial growth of the fetal eye and evaluation of the hyaloid artery: in utero ultrasonographic study

Wide-field digital imaging system for assessing ocular anterior segment development in very preterm infants

Purpose

This study aims to longitudinally investigate developments of the anterior segment in very preterm infants who exhibit normal retinal development outcomes by utilizing a wide-field digital imaging system.

Methods

Between June 2021 and June 2022, neonates with a birth weight of <1500 g and/or a gestational age (GA) of less than 32 weeks were included in this study. The participants underwent regular ocular examinations, including sequential evaluations of the anterior segment and the retina, at intervals of 2-5 weeks, starting from birth and continuing until they reached a corrected GA of 48 weeks. Term neonates were selected as normal controls for the study. The study recorded the weight and GA of subjects at the time of examination, as well as indicators of abnormal development in the anterior segment.

Results

A total of 48 very preterm infants with normal retinal developmental outcomes were enrolled. The control group included 59 full-term infants. Common anterior segment eye abnormalities such as persistent hyperplasia of primary vitreous, persistent pupillary membranes, iris vessels, and anterior chamber angle vessels gradually subsided with the period in very preterm infants. The vascularity of the iris was substantially higher than in term controls (P < 0.05) at term gestation. The imaging of iris vessels and anterior chamber angle vessels in very preterm infants exhibited a decline at 46 and 47 weeks, respectively, which occurred slightly later compared to term infants.

Conclusion

In very preterm infant s with normal outcomes, although the developmental process is delayed, they may form a normal anterior segment structure similar to that of full-term infants in the late stages, which is followed up by the wide-field digital imaging system.

Management and outcomes of posterior persistent fetal vasculature

PURPOSE

To describe the clinical features, management and outcomes of posterior persistent fetal vasculature (PFV) and suggest a management algorithm.

DESIGN

Retrospective consecutive case series.

PARTICIPANTS

All children diagnosed with posterior PFV and treated or followed at the Rothschild Foundation Hospital in France between June 2011 and September 2021.

METHODS

Retrospective analysis of the clinical characteristics of posterior PFV. We reported at diagnosis: age, gender, presenting symptoms, intraocular pressure (IOP), visual acuity (VA). Patients were divided in four group depending on severity and involvement or not of the anterior segment. We reported the vitreoretinal surgical techniques used.

MAIN OUTCOME MEASURES

Anatomical results, ocular hypertension, BCVA, presence of post-operative adverse events and additional surgical interventions were recorded at each follow-up visit.

RESULTS

A total of 96 patients were included. Median age at diagnosis was 8 months (mean 18.9±30.9 months) with a mean follow-up of 27±31.2 months. Although PFV is often an isolated disease, it was associated with a systemic disease in 8% of cases. Posterior PFV was associated with anterior involvement in 62 eyes (64%). Forty-one eyes (42.7%) were microphthalmic and were more frequently associated with severe PFV [53% vs. 25%; (p=0.01)]. Surgery was performed in 85 patients (89%). Of them, 69 (81%) were a total success, 5 (6%) were a partial success due to a persistent limited peripheral retinal detachment (RD), and 11 (13%) were a failure due to persistent total RD after surgery. Twenty-four eyes presented post-operative adverse events including ocular hypertension requiring eye drop medication (6.6%), secondary cell proliferation around the IOL (7.7%), intravitreal hemorrhages (6.6%), persistent tractional RD (9.9%). A second surgery was performed in 15 patients (16%). At last follow-up, VA could be measured in logMAR in 43 children (45%), was light perception in 21 eyes (22%), and no light perception or impossible to assess in 32 eyes (33%).

CONCLUSIONS

In our case-series, most of patients presenting PFV with posterior involvement received complex vitreoretinal surgery. Goals of the surgery varies, and include retinal flattening, reduction of vitreoretinal traction, freeing of the visual axis and aesthetic concerns. We proposed a surgical and medical management algorithm for PFV.

Refractive development I: Biometric changes during emmetropisation

PURPOSE

Although there are many reports on ocular growth, these data are often fragmented into separate parameters or for limited age ranges. This work intends to create an overview of normal eye growth (i.e., in absence of myopisation) for the period before birth until 18 years of age.

METHODS

The data for this analysis were taken from a search of six literature databases using keywords such as "[Parameter] & [age group]", with [Parameter] the ocular parameter under study and [age group] an indication of age. This yielded 34,409 references that, after screening of title, abstract and text, left 294 references with usable data. Where possible, additional parameters were calculated, such as the Bennett crystalline lens power, whole eye power and axial power.

RESULTS

There were 3422 average values for 17 parameters, calculated over a combined total of 679,398 individually measured or calculated values. The age-related change in refractive error was best fitted by a sum of four exponentials (r²  = 0.58), while all other biometric parameters could be fitted well by a sum of two exponentials and a linear term ('bi-exponential function'; r² range: 0.64-0.99). The first exponential of the bi-exponential fits typically reached 95% of its end value before 18 months, suggesting that these reached genetically pre-programmed passive growth. The second exponentials reached this point between 4 years of age for the anterior curvature and well past adulthood for most lenticular dimensions, suggesting that this part represents the active control underlying emmetropisation. The ocular components each have different growth rates, but growth rate changes occur simultaneously at first and then act independently after birth.

CONCLUSIONS

Most biometric parameters grow according to a bi-exponential pattern associated with passive and actively modulated eye growth. This may form an interesting reference to understand myopisation.

Natural Course of Fetal Hyaloid Artery: SlowflowHD Longitudinal Study

OBJECTIVE

To assess the natural course of the fetal hyaloid artery (FHA) using SlowflowHD during pregnancy.

METHODS

One-hundred and eighteen normal fetuses were studied longitudinally using SlowflowHD to assess the natural course of FHA at 18-21 + 6, 28-31 + 6, and after 35 weeks of gestation. Blood flow of FHA with/without its branches (BF) was evaluated using SlowflowHD, and the band of FHA without blood flow (Band) was identified in each gestational period. The natural course of FHA was classified into six types: Type A, not detected (ND) in each gestational period; Type B, Band at 18-21 + 6 weeks; Type C, Band at 18-21 + 6 and 28-31 + 6 weeks; Type D, BF at 18-21 + 6 weeks; Type E, BF at 18-21 + 6 weeks and Band at 28-31 + 6 weeks; Type F, BF at 18-21 + 6 and 28-31 + 6 weeks.

RESULTS

BF, Band, and ND were 83.5, 15.5, and 1.0% at 18-21 + 6 weeks, 8.8, 15.5, and 75.7% at 28-31 + 6 weeks, and 0, 0, and 100% after 35 weeks, respectively. Type A was 1.0%, Type B was 13.6%, Type C was 1.9%, Type D was 61.2%, Type E was 13.6%, and Type F was 8.7%.

CONCLUSIONS

The presence of FHA blood flow before 30 weeks of gestation should be regarded as a physiologic phenomenon in normal fetuses.

Prevalence and Risk Factors of Myopia in Young Adults: Review of Findings From the Raine Study

Myopia tends to develop and progress fastest during childhood, and the age of stabilization has been reported to be 15-16 years old. Thus, most studies on myopia have centered on children. Data on the refractive error profile in young adulthood - a time in life when myopia is thought to have stabilized and refractive error is unaffected by age-related pathology such as cataract - are limited. The Raine Study has been following a community-based cohort of young adults representative of the general Western Australia population since their prenatal periods in 1989-1991, with eye examinations performed when participants were 20 and 28 years old. At 20 years old, prevalence of myopia in the cohort was 25.8%. Using long-term trajectory of serum vitamin D levels and conjunctival ultraviolet autofluorescence (CUVAF) area to objectively quantify sun exposure, the Raine Study confirmed a negative relationship between time spent outdoors and myopia prevalence. However, prospective studies are required to determine the amount of CUVAF area or serum vitamin D levels associated with time duration. Combining data from the Raine Study and several other cohorts, Mendelian randomization studies have confirmed a link between myopia and a genetic predisposition toward higher education. Several novel potential associations of myopia or ocular biometry were investigated, including fetal growth trajectory, which was found to be significantly associated with corneal curvature at 20 years. By age 28, myopia prevalence had increased to 33.2%. Between 20 and 28 years old, myopia progressed and axial length elongated, on average, by -0.041D/year and 0.02 mm/year, respectively. Smaller CUVAF area at follow-up, female sex, and parental myopia were significant risk factors for myopia incidence and progression between 20 and 28 years. Given the limited research in young adults, further investigations are warranted to confirm the Raine Study findings, as well as identify novel genetic or environmental factors of myopia incidence and progression in this age group.

Reference standards for facial measurements in early third trimester South African fetuses, and the effect of maternal and fetal characteristics

Fetal alcohol spectrum disorder (FASD) is a major problem worldwide and dysmorphic facial features may be a prenatal biomarker for FASD. Deviations from normal facial development cannot be explored before establishing the normal variation in a specific population, since ethnic differences may exist.Objectives: Main objective: to establish reference standards for 23 facial measurements on 3D ultrasound volumes obtained between days 196 and 224 of gestation in healthy unexposed South African fetuses from an area with historically high alcohol consumption prevalence and a population group with no existing normative values. Secondary objective: to assess the confounding effect of maternal and fetal characteristics.Design: This study involves 97 women (including 43 smokers) who had been enrolled in the Safe Passage Study (SPS), a large prospective multinational cohort study assessing the effects of prenatal alcohol exposure. They had adequate 3 D ultrasound volumes of the fetal face acquired at 28⁺⁰-31⁺⁶weeks in singleton pregnancies without comorbidities, congenital abnormalities or exposure to alcohol, marijuana, or methamphetamines from 4 weeks before conception.Participants, materials, setting, methods: The participants were recruited from two residential areas of low socioeconomic status in Cape Town. Meticulous information was collected on maternal and pregnancy characteristics, including alcohol use at different time points. Gestational age (GA) was based on ultrasound biometry before 24 weeks, and 3D ultrasound volumes were acquired trans-abdominally from a sagittal and axial plane of the fetal face. Volumes were independently assessed offline by two observers and the image with the best landmark definition was used for 23 facial measurements, representing features previously described in children with FASD. The relation to the exact GA was assessed by regression analysis, the expected mean value and standard error of the estimate (SEE) was determined to transform all raw measurements into z-scores, and the effect of possible confounders on z-scores was assessed by ANOVA.Results: Ten variables changed significantly with advancing GA (extraocular diameter, anteroposterior, medio-lateral and supero-inferior ocular diameter, ocular volume, interlens distance, prenasal thickness, nasal bone length, nose length and nose protrusion) and thirteen did not (interocular distance; interocular: extraocular diameter ratio, prenasal thickness: nasal bone length ratio, pronasal-subnasal distance, subnasal-mouth distance, philtrum length, upper vermillion thickness, nose-philtrum angle, maxillary angle, facial height, facial protrusion, frontomaxillary facial angle and maxilla-nasion-mandible angle). Reference values (expected mean and SEE) for the 23 measurements were established for each day.The z-scores of all facial measurements were not independently affected by maternal age, parity, gravidity, smoking or body mass index, but infant sex and birthweight z-score significantly influenced several z-scores (infant sex for extraocular, medio-lateral, and supero-inferior ocular diameter, ocular volume, prenasal thickness and nose protrusion; birthweight z-score for extraocular diameter, interocular and interlens distance, nose protrusion and maxillary angle).Limitations: GA was not always confirmed by first trimester ultrasound and some measurements could not be obtained in all cases due to suboptimal image quality. The cohort included few heavy smokers so an effect of heavy or continued smoking cannot be ruled out, and the effect of ethnicity was not assessed.Conclusions: These are the first local reference standards for fetal facial measurements and, to our knowledge, the first reference standards for the supero-inferior ocular diameter, face protrusion, upper vermillion thickness, maxillary angle, and nose-philtrum angle. They were broadly in keeping with published references, with small discrepancies explained by minor differences in technique. Even in this narrow GA window, the distribution of many variables changed over time and normal variation was significantly influenced by fetal sex and birthweight z-score. The possible confounding effect of these factors needs to be considered when assessing the impact of harmful exposures like alcohol on facial development.

Associations Between Fetal Growth Trajectories and the Development of Myopia by 20 Years of Age

Purpose

To evaluate the contribution of genetic and early life environmental factors, as reflected by fetal anthropometric growth trajectories, toward the development of myopia during childhood and adolescence.

Methods

This analysis included 498 singleton Caucasian participants from the Raine Study, a pregnancy cohort study based in Western Australia. Serial fetal biometric measurements of these participants were collected via ultrasound scans performed at 18, 24, 28, 34, and 38 weeks’ gestation. At a 20-year follow-up, the participants underwent a comprehensive ophthalmic examination, including cycloplegic autorefraction and ocular biometry measurements. Using a group-based trajectory modeling approach, we identified groups of participants with similar growth trajectories based on measurements of fetal head circumference (HC), abdominal circumference, femur length (FL), and estimated fetal weight (EFW). Differences between trajectory groups with respect to prevalence of myopia, axial length (AL), and corneal radius of curvature measured at the 20-year follow-up were evaluated via logistic regression and analysis of variance.

Results

Prevalence of myopia was highest among participants with consistently short or consistently long FLs (P = 0.04). There was also a trend toward increased prevalence with larger HC in late gestation, although not at a statistically significant level. Trajectory groups reflecting faster HC, FL, or EFW growth correlated with significantly flatter corneas (P = 0.03, P = 0.04, and P = 0.01, respectively) and a general, but not statistically significant, increase in AL.

Conclusions

Environmental or genetic factors influencing intrauterine skeletal growth may concurrently affect ocular development, with effects persisting into adulthood.

Longitudinal Analysis of Refractive Errors in Premature Children during the First Three Years of Life

PURPOSE

To examine the longitudinal behavior of refractive errors in both retinopathy of prematurity (ROP) and non-ROP screened premature children during the first three years of life.

METHODS

This retrospective cohort included premature children (less than 37 weeks gestational age) born between 10/2011 and 8/2013 with ≥ two cycloplegic refractions. Cycloplegic refractions were converted into power vectors: M (spherical equivalent), J₀ [positive for with-the-rule (WTR) and negative for against-the-rule (ATR) astigmatism], and J ₄₅ (oblique astigmatism). Each power vector component was fitted by multilevel mixed-effects linear regression models; the mean change over time was analyzed.

RESULTS

Mean J₀ was 0.59 (95% CI 0.53-0.66) at six months and 0.29 (95% CI 0.19-0.39) at 18 months; afterward, the change was <0.1 per year. J₀ decreased -0.32 (0.64 diopters) over three years. When analyzed in one-year increments, the mean change in J₀ and M was lowest at 24 months. M decreased 1.13 diopters over three years.

CONCLUSION

WTR astigmatism and spherical equivalent decreased over the first three years of life. WTR astigmatism accounted for the majority of amblyopogenic refractive errors. The change in J₀ leveled after 18 months and the lowest rate of change was at 24 months in J₀ and M, thus it may be appropriate to screen this high-risk population around 18-24 months.

OCT angiography of persistent hyaloid artery: a case report

Background

A persistent hyaloid artery is a rare fetal remnant. Several complications such as amblyopia, vitreous hemorrhage, and retinal detachment have been reported. Here, we present a case of vitreous hemorrhage with a persistent hyaloid artery.

Case presentation

A healthy 16-year-old male presented with blurred vision in his left eye. Vitreous hemorrhage occurred and absorbed spontaneously. Slit-lamp examination demonstrated a Mittendorf’s dot and fundus examination revealed a persistent hyaloid artery. Optical coherence tomography (OCT) showed a Bergmeister’s papilla. The blood flow of the persistent hyaloid artery via the Bergmeister’s papilla was found by OCT angiography.

Conclusion

The persistent hyaloid artery should be considered as a cause of spontaneous vitreous hemorrhage of young healthy patient. The OCT angiography will be a useful noninvasive approach to confirm the patency of the persistent hyaloid artery.

Prenatal diagnosis and implications of microphthalmia and anophthalmia with a review of current ultrasound guidelines: two case reports

BACKGROUND

Microphthalmia and anophthalmia are rare congenital fetal abnormalities. The combined incidence is estimated at 1 in 10,000 births. These two conditions arise from complex and incompletely understood genetic and/or environmental causes. Prenatal diagnosis is neither frequent nor easy and relies on precise, high-quality ultrasonography. Current antenatal ultrasound protocols for imaging of the fetal eye are inconsistent and inadequate to screen for the spectrum of ocular malformations, and there are no clear guidelines on detection of these rare abnormalities. Our study of two cases highlights the importance of early detection, and we review current practice and suggest a definitive fetal imaging protocol.

CASE PRESENTATION

We present two antenatal cases, one each of microphthalmia and anophthalmia, both diagnosed at the morphology scan at our tertiary fetal medicine unit. In both cases, the parents (a 36-year-old woman of Mauritanian ethnicity and a non-consanguineous partner of Nepalese descent, and a 31-year-old Caucasian woman and non-consanguineous Caucasian partner) elected to terminate their pregnancies and made unremarkable recoveries. Subsequent fetal autopsy confirmed the ultrasound scan findings.

CONCLUSIONS

We recommend that antenatal ultrasound guidelines are updated to specify use of a curvilinear transducer (2-9 MHz) to image both orbits in the axial and coronal planes, aided by use of a transvaginal probe when the transabdominal approach is inadequate to generate these images. When applicable, three-dimensional reverse-face imaging should be obtained to aid the diagnosis. The presence, absence, or non-visualization of lenses and hyaloid arteries should be documented in reports and these cases referred for a tertiary-level ultrasound scan and fetal medicine review. Imaging of the orbits should occur from 12 weeks' gestation. Magnetic resonance imaging and amniocentesis with chromosome microarray testing may provide additional genetic and structural information that may affect the overall morbidity associated with a diagnosis of microphthalmia or anophthalmia.

Prenatal Sonographic Abnormal Appearances of the Fetal Hyaloid Artery: From Normal Variants to Pathology

This is a case series on the abnormal sonographic appearance and outcome of the fetal hyaloid artery (HA) detected during between 1987 and 2015 at one medical center. Fifteen cases were detected during fetal anatomy scans, usually performed at 14 to 16 weeks' gestation. Three other cases were diagnosed following referral for a second opinion. In nine fetuses, the HA regressed normally throughout pregnancy. Of them, eight neonates had normal outcomes and one had cataract at the same eye. All nine other cases ended with adverse outcomes. Failure of the HA to regress in the third trimester appears to be an indicator of congenital blindness.

Prenatal Diagnosis of Persistent Hyperplastic Primary Vitreous: Report of 2 Cases and Review of the Literature

Persistent hyperplastic primary vitreous is a spectrum of congenital ocular abnormalities characterized by leukocoria, microphthalmia, cataracts, extensive intravitreal hemorrhage, persistence of the hyaloid artery, glaucoma, and retinal detachment. It might be isolated or associated with congenital syndromes such as trisomy 13, Walker-Warburg syndrome, and Norrie disease. We present 2 cases of persistent hyperplastic primary vitreous diagnosed by prenatal sonography in the early third trimester. Bilateral hyperechoic lenses and retinal nonattachment were detected in the sonographic examination of the first case, whereas irregular echogenic bands between the lenses and posterior walls of the eyes were prominent in the second case. In both of the cases, ocular findings were accompanied by intracranial findings, including severe hydrocephalus, an abnormal gyral pattern, and cerebellar hypoplasia, suggesting the diagnosis of Walker-Warburg syndrome. We also present a review of the literature regarding the prenatal diagnosis of this malformation.

Normal Developmental Globe Morphology on Fetal MR Imaging

BACKGROUND AND PURPOSE

Age-dependent structural changes of the globes occur during gestation. The posterolateral globe margins bulge outward, and the eyes are conical in early gestation. Later, the globes are ellipsoid. The purpose of this study was to establish normal developmental fetal globe morphology.

MATERIALS AND METHODS

The fetal MR imaging data base at an academic children's hospital was queried for all brain MRIs performed during 8 years. Motion artifacts, brain/craniofacial/globe malformations, and chromosomal defects were exclusion criteria. Two board-certified neuroradiologists evaluated each examination for globe shape (elliptic/nonelliptic) and hyaloid visibility. Logistic regression was used to evaluate correlations among variables. Age-specific cut-points for globe shape and hyaloid visibility were chosen to optimize specificity.

RESULTS

We identified 1243 examinations from 1177 patients. Six hundred eighty-two examinations met the inclusion criteria (17-39 weeks). Receiver operating characteristic analysis showed that age was highly predictive of globe shape (area under the curve = 0.99) and fetal vasculature visibility (area under the curve = 0.94). Nonelliptic globes were universal up to 22 weeks. Thereafter, globes gradually assumed an elliptic shape, present in nearly all patients 29 weeks and older (sensitivity, 81%; 95% CI, 76%-85%; specificity, 99%; 95% CI, 98%-100%). The hyaloid vasculature was visible in most patients up to 19 weeks and occasionally in those at 20-24 weeks, but never in those 25 weeks and older (sensitivity, 69%; 95% CI, 65%-72%; specificity, 100%; 95% CI, 95%-100%).

CONCLUSIONS

Physiologic nonspheric globe shapes are normal up to 29 weeks' gestation and should not be misinterpreted as pathologic. Thereafter, globes are generally elliptic. The timing of this process coincides with the resolution of the primary vitreous and may be related.

Evaluation of structural contributors in myopic eyes of preterm and full-term children

PURPOSE

We conducted a cross-sectional study to test the hypothesis that the structural contributions to myopia in preterm and full-term born children are different.

METHODS

In this study, 93 children ranging from ages 2 to 13 who had myopia ≥ -3 diopters in at least one eye were examined with A-scans. The following data was collected and analyzed: history of birth, refractive error (RE), cornea thickness (CT) and average corneal curvature (AVK), depth of anterior chamber (ACD), lens thickness (LT), and axial length (AL) of the eye.

RESULTS

Eyes were tested and categorized into four groups: myopic eyes in full-term children (group 1), myopic eyes in premature children (group 2), non-myopic eyes in full-term children (group 3), and non-myopic eyes in preterm children (group 4). The RE were similar between group 1 and group2, and between group 3 and group 4. Myopic eyes in group 2 had higher AVK as compared to group 3; 45.4 ± 0.4 D vs. 43.5 ± 0.7 D, p = 0.008. The ACD in group 2 was shallower than that in group 1 (2.5 ± 0.5 vs. 3.2 ± 0.3, p = 0.01). The LT measurements in group 2 were thicker than those in group 1 (mean LT = 4.9 ± 1.0 vs 4.1 ± 0.3 mm, p = 0.001, respectively). Finally, AL of myopic eyes in group 1 was longer than that of group 2, p = 0.01.

CONCLUSION

These results suggest that increased axial length plays an important role in myopia in full-term children, whereas corneal curvature and lens thickness are major contributors to myopia in preterm children.

Normative biometrics for fetal ocular growth using volumetric MRI reconstruction

OBJECTIVE

To determine normative ranges for fetal ocular biometrics between 19 and 38 weeks gestational age (GA) using volumetric MRI reconstruction.

METHOD

The 3D images of 114 healthy fetuses between 19 and 38 weeks GA were created using super-resolution volume reconstructions from MRI slice acquisitions. These 3D images were semi-automatically segmented to measure fetal orbit volume, binocular distance (BOD), interocular distance (IOD), and ocular diameter (OD).

RESULTS

All biometry correlated with GA (Volume, Pearson's correlation coefficient (CC) = 0.9680; BOD, CC = 0.9552; OD, CC = 0.9445; and IOD, CC = 0.8429), and growth curves were plotted against linear and quadratic growth models. Regression analysis showed quadratic models to best fit BOD, IOD, and OD and a linear model to best fit volume.

CONCLUSION

Orbital volume had the greatest correlation with GA, although BOD and OD also showed strong correlation. The normative data found in this study may be helpful for the detection of congenital fetal anomalies with more consistent measurements than are currently available. © 2015 John Wiley & Sons, Ltd.

A New Field of ‘Fetal Sono-ophthalmology’ by 3D HDlive Silhouette and Flow

Diagnostic ultrasound technology has remarkably evolved and contributed to accurate prenatal diagnosis and management. HDlive silhouette and HDlive flow are new applications of threedimensional (3D) ultrasound technology. The algorism of HDlive silhouette creates a gradient at organ boundaries where an abrupt change of the acoustic impedance exists within tissues. HDlive silhouette and flow can be called as ‘see-through fashion’. The advantages of this ‘see-through fashion’ imaging are comprehensive orientation and persuasive localization of inner structure as well as of fetal angiostructure inside the morphological structure. Picture of the month demonstrates the fetal eye at 19 weeks of gestation. The lens, vitreous body and hyaloid artery inside the vitreous humor are well demonstrated. The hyaloid artery is retrogressing during pregnancy and no remnant hyaloid artery is visible in most of mature neonates. Therefore, hyaloid artery can be observed in only young fetuses and immature neonates. HDlive silhouette and flow has enabled us to depict fetal eye and ocular vascularity three-dimensionally. This new technology has a great potential to open a new field of ‘fetal 3D sono-ophthalmology’, which has been never invented by conventional ultrasound technology.

How to cite this article

Pooh RK. A New Field of ‘Fetal Sonoophthalmology’ by 3D HDlive Silhouette and Flow. Donald School J Ultrasound Obstet Gynecol 2015;9(3):221-222.

Isolated congenital hereditary cataract in a dizygotic twin: prenatal ultrasonographic diagnosis

Cataract, defined as opacity of the lens in one or both eyes, is a major cause of blindness throughout the world, and not uncommon, particularly in the elderly population. However, congenital cataracts are rare and occur with a frequency of 30 cases in 100,000 births. About one-third of the cases fall into the group inherited without systemic abnormality. Importantly, congenital cataracts produce deprivation amblyopia, refractive amblyopia, and retinal detachment, leading to lifelong visual impairment. Successful management is dependent on early diagnosis and referral for surgery when indicated. Here we present a case of hereditary bilateral cataracts in a dizygotic twin detected on prenatal ultrasound examinations and postnatally confirmed as congenital cataracts associated with posterior lenticonus.

Fetal ocular measurements by three-dimensional ultrasound

PURPOSE

To establish a reference range for normal fetal eye volume (FEV) by three-dimensional ultrasound using Virtual Organ Computer-aided AnaLysis (VOCAL) method and compare the reproducibility between the two trace modes (manual and sphere).

METHODS

This prospective, longitudinal observational study was performed at a single center and involved 71 eyes of 37 fetuses between 17 and 40 weeks of gestational age. Only pregnancies without fetal growth restriction, diabetes mellitus, hypertension, or major fetal malformation were included. Fetuses' eye measurements were obtained by a single observer during routine ultrasonographic examination.

RESULTS

Mean FEV manual mode ranged from 309.5 ± 80.1 mm(3) at 17-18 weeks to 2552.1 ± 384.9 mm(3) at 39-40 weeks. Mean FEV sphere mode ranged from 394.8 ± 71.8 mm(3) at 17-18 weeks to 2682.1 ± 343.4 mm(3) at 39-40 weeks. Correlations ranged from R² = 0.85 (transversal diameter and gestational age) to R² = 0.91 (FEV sphere mode and gestational age). All correlations were statistically significant (P < 0.001). Although highly correlated (R² = 0.97, P < 0.001), there was a fixed bias between manual and sphere measurements. The agreement between these measurements showed no proportional bias (P = 0.89).

CONCLUSIONS

The present study establishes reference values for FEV using the VOCAL method manual mode. These normal growth parameters can be used in routine ultrasound assessment of the fetal eye, especially in families at risk of genetic diseases that affect ocular growth, such as congenital glaucoma.

Prenatal ultrasonographic detection of ophthalmic diseases

Four patients with prenatal sonographic findings suggestive of ophthalmic pathology were detected in utero. The definitive diagnoses of infantile fibrosarcoma, persistent hyperplastic primary vitreous/persistent fetal vasculature, Fraser syndrome, and microphthalmia with coloboma and retrobulbar cyst were made postnatally. High-resolution intrauterine sonograms expedited ophthalmic referral and influenced prenatal planning.

Fetal ocular measurements by MRI

OBJECTIVE

To present fetal magnetic resonance imaging (MRI) ocular measurement ranges by gestational age (GA) in normal and growth-restricted fetuses.

METHODS

A total of 298 pregnant women from the 18th to the 39th week of gestation were imaged using MRI. Ocular measurements including binocular distance (BOD), interocular distance (IOD), transverse ocular diameter (OD) and anterior-posterior (AP) OD were measured. The curve estimation analyses for linear, logarithmic and quadratic models were performed. The ocular measurements of the fetuses with intrauterine growth restriction (IUGR) were compared with that of the normal fetuses.

RESULTS

The fetal eye resembles an ellipsoid with significantly longer OD and shorter AP (t = - 22.07, p < 0.001). The quadratic model was the best model in predicting growth of the fetal BOD, IOD, OD and AP. The ocular measurements of the fetuses with IUGR were significantly different from that of the normal fetuses (BOD: t = 3.58, p < 0.001; IOD: t = 5.73, p < 0.001; OD: t = 3.52, p < 0.001; AP: t = 2.19, p < 0.05).

CONCLUSION

Fetal ocular growth can be readily assessed by fetal MRI. Using the normative data provided in this study, fetal ocular anomalies may be detected. Ocular size is frequently reduced in the condition of IUGR, with potential pathologic impact on postnatal vision.

Fetal interlens distance: normal values during pregnancy

OBJECTIVES

The aims of this study were to establish normal ranges of values for interlens distance (ILD) during gestation, and to assess the correlation between ILD and growth of the orbits and other fetal biometric parameters.

METHODS

A cross-sectional study of morphologically normal, singleton fetuses was carried out in low-risk pregnant women. We measured the distance between the centers of the fetal lenses from 12 to 37 completed weeks of gestation. An oblique anterior coronal section was used to measure the ILD. The biorbital diameter (BOD) was measured in the same plane. We analyzed the correlation between the ILD and gestational age (GA), BOD, biparietal diameter (BPD), head circumference (HC), femur length (FL) and abdominal circumference (AC). Fetal gender was assessed to evaluate possible significant differences.

RESULTS

Four hundred and fifty normal fetuses were recruited for the study. In 427 fetuses appropriate ILD measurements were obtained, and complete evaluation of all parameters was accomplished in 377 of these. ILD demonstrated a high positive correlation with GA (r(2) = 0.969), BPD (r(2) = 0.959), HC (r(2) = 0.962), AC (r(2) = 0.949) and FL (r(2) = 0.956) as pregnancy advanced. The mean BOD : ILD ratio was 1.50 +/- 0.08, remaining constant throughout pregnancy (linear regression r(2) = 0.006). No statistically significant differences were found between genders for mean ILD and GA of the study population (P = 0.604 and 0.595, respectively).

CONCLUSIONS

The results of this study confirm previous hypotheses regarding the close relationship between eyeball growth and growth of the surrounding bony structures. Measurement of fetal ILD, which can be used interchangeably with BOD measurement in either the axial or coronal plane, can be taken to reflect the expected development of the fetal orbits whilst simultaneously providing valuable information on eyeball development. It is likely that ILD could be used as a complementary tool in the elaboration of various severe abnormalities, mainly related to craniofacial and nervous system malformations.

Fetal eyeball volume: relationship to gestational age and biparietal diameter

OBJECTIVE

To measure and determine normal values of the fetal eyeball volume between 14 and 40 weeks of gestation.

METHODS

The volume of the fetal eyeball was measured with three-dimensional ultrasound between 14 and 40 weeks of gestation using the VOCAL software.Only singleton pregnancies without fetal growth restriction, diabetes mellitus, hypertension or major fetal malformation were included.

RESULTS

Over all, 203 women were studied. In 125 both eyeballs were measured while in 78 only one eyeball was measured. The volume of the eyeball correlated strongly with gestational age (right: R = 0.946, P < 0.001, n = 171. left: R = 0.945, P < 0.001, n = 156), and with the biparietal diameter (BPD) (right: R = 0.949, P < 0.001, n = 171. left: R = 0.953, P < 0.001, n = 156). Using regression analysis the best correlation between eyeball volume and the BPD were: square of right eyeball = -0.180 + 0.187 BPD, square of left eyeball = -0.182 + 0.187 BPD.

CONCLUSIONS

The volume of the eyeball has strong positive correlations with gestational age and BPD. Our data may be helpful in fetuses suspected of having eye anomalies.

In utero eye development documented by fetal MR imaging

BACKGROUND AND PURPOSE

To date, very limited attention has been given to ocular abnormalities or growth parameters detected by fetal MR imaging. Our objective was to retrospectively determine the relationship between different parameters of eye development and estimated gestational age in the human fetus by use of fetal MR imaging.

MATERIALS AND METHODS

A retrospective study was performed to measure the transverse diameter, interocular distance, and lens diameter of the globes of 127 fetuses who had a morphologically normal central nervous system. Multiple single-shot T2 fast spin-echo images were obtained with a 1.5T magnet by use of contiguous 3-mm intervals in at least 2 orthogonal planes. Loess curves were fitted to explore the relationship between gestational age and each of the 3 measurements of interest. Different models were compared statistically to determine the model of best fit.

RESULTS

For each variable of interest, the "best" model of eye growth was a quadratic function. Specifically, lens growth seems to plateau after 36 weeks of gestation, interocular distance plateaus after 36 weeks of gestation, and globe growth plateaus after 42 weeks of gestation.

CONCLUSIONS

The lens, orbit, and interocular distance growth of the fetus can be demonstrated on fetal MR imaging. All 3 measurements suggest a quadratic model of growth, which indicates slowing of growth toward the end of gestation.

Congenital axial high myopia detected by prenatal ultrasound

High-resolution prenatal ultrasound can allow for early detection and monitoring of many fetal anomalies, including those involving the globe and orbit. The authors present a case of congenital axial high myopia that was diagnosed at 33 gestational weeks and monitored by prenatal ultrasonography. Some systemic abnormalities that can be associated with congenital high myopia are reviewed. High ammetropias, anisometropia, and either axial myopia or axial hyperopia can be detected in utero and give this early detection a greater chance of treating and reversing the devastating effects of amblyopia.

MRI of the fetal eyes: morphologic and biometric assessment for abnormal development with ultrasonographic and clinicopathologic correlation

BACKGROUND

Currently ocular biometric measurements are defined by US and are measured from the orbital walls. These bony landmarks cannot be seen by MRI, and therefore these measurements cannot be directly applied.

OBJECTIVE

To define measurements of normal growth of the fetal eyes using MRI.

MATERIALS AND METHODS

Transorbital views were analyzed in 198 fetal MR examinations. The ocular diameter (OD) and interocular and binocular distances (IOD and BOD) were measured and were plotted against gestational age. Fetuses with abnormalities affecting the eyes were evaluated separately.

RESULTS

Of 198 scans, 146 had suitable images, 35 of which were abnormal. Normal growth of BOD, IOD and OD were determined, and compared with the respective already established US data.

CONCLUSION

Normal growth charts were derived from a cohort of 111 normal fetuses. Because the margins of the vitreous are inside the bony orbit, at the same gestational age measurements of the BOD and OD are always less than the corresponding measurements by US, and those of the IOD are always more. Normal growth charts for MRI can now be used to support suspected diagnoses of orbital and ocular pathologies and the syndromes that give rise to them, and many examples are demonstrated.

Prenatal ultrasonographic diagnosis of persistent hyperplastic primary vitreous

Persistent hyperplastic primary vitreous (PHPV) is a rare developmental malformation of the eye characterized by the presence of a vascular membrane located behind the lens. We report, for the first time in the literature, the identification on ultrasound examination of bilateral cataract and thickened hyaloid artery-lens junction, leading to a diagnosis of bilateral PHPV, in a fetus at 23 weeks' gestation. Histological examination at postmortem confirmed the prenatal diagnosis of bilateral PHPV and cataract. A thorough ultrasound examination of the fetal eye in cases with cataract is recommended.

Ophthalmological problems associated with preterm birth

As survival of preterm infants improves, the long-term care of consequent ophthalmic problems is an expanding field. Preterm birth can inflict a host of challenges on the developing ocular system, resulting in the visual manifestations of varied significance and pathological scope. The ophthalmic condition most commonly associated with preterm birth is retinopathy of prematurity, which has the potential to result in devastating vision loss. However, the visual compromise from increased incidence of refractive errors, strabismus, and cerebral vision impairment has significant impact on visual function, which also has influence on other developmental aspects including psychological and educational. In this review, the normal ocular development is discussed, aiming to exemplify the impact of early exteriorisation on one of the more naive organs of prematurity. This is then related to the incidence and visual consequences of many types of deficit, including refractive error, strabismus, and loss of visual function in preterm populations, with comparisons to term infant studies. Often these conditions are linked with causal and resultant factors being impossible to segregate, but the common factor of increased rates of all types of ophthalmic deficits demonstrates that children born prematurely are indeed premature for life.

The cone electroretinogram in retinopathy of prematurity

PURPOSE

To test the hypothesis that retinopathy of prematurity (ROP) affects the cone photoreceptors less than the rod photoreceptors.

METHODS

Electroretinogram (ERG) responses to a 1.8-log-unit range of red flashes on a white, rod-saturating background were recorded in 42 subjects with a history of preterm birth and ROP (28 untreated; 6 treated) or no ROP (n = 8). The sensitivity (S(CONE)) and saturated amplitude (R(CONE)) of the cone photoresponse were calculated by fit of a model of the activation of cone phototransduction to the a-waves. The cone-driven b-wave amplitude was evaluated as a function of stimulus intensity. S(CONE) and R(CONE) were compared to the rod response parameters (S(ROD), R(ROD)) recorded from the same preterm subjects. Responses in the former preterm subjects were compared to those in control subjects.

RESULTS

The values of S(CONE) and R(CONE) in the preterm subjects overlapped broadly with those in the control subjects. The shapes of the b-wave stimulus-response functions did not differ between preterm and control subjects. The relative value of S(CONE) was significantly greater than that of S(ROD).

CONCLUSIONS

ROP has less effect on the cone than on the rod photoresponses, suggesting that cones are more resistant to the ROP disease process. The similar shape of the b-wave stimulus-response function in preterms and control subjects is evidence that ROP does not alter the balance of ON and OFF signals in the cone pathway.

Development of scotopic visual thresholds in retinopathy of prematurity

PURPOSE

To test the hypothesis that the late-maturing parafoveal rod photoreceptors are more vulnerable than peripheral rods to the effects of retinopathy of prematurity (ROP).

METHODS

Twenty-four infants with a history of preterm birth (gestational age at birth </=31 weeks) participated in a longitudinal study: 12 had mild ROP that resolved without treatment, and 12 had never had ROP. Thresholds for detecting stimuli (2 degrees diameter, 50 ms duration) presented 10 degrees (parafoveal) and 30 degrees (peripheral) from a central fixation target were estimated by using a preferential-looking

METHOD

At each visit, thresholds at both sites were obtained in random order. Thresholds of the preterm subjects were compared with those of previously reported term infants.

RESULTS

The course of threshold maturation in subjects with ROP was significantly prolonged (P </= 0.01) compared with those who had never had ROP and with term-born control subjects. On average, parafoveal thresholds in subjects with ROP reached the adult level at a median age of 12 (range, 6-18) months, and peripheral thresholds reached the adult level at 9 (range, 5-12) months. Median thresholds in subjects who had never had ROP reached adult levels at both sites by approximately 7 months.

CONCLUSIONS

The slower development of parafoveal compared with peripheral thresholds in subjects with a history of ROP is evidence that the late-maturing parafoveal rods are more affected by the ROP disease process.

ERG oscillatory potentials in infants

PURPOSE

Study the scotopic and photopic oscillatory potentials (OPs) of the electroretinogram (ERG) in 10-week old infants.

METHODS

Term-born 10-week old infants (n = 15) and adults (n = 12) were tested. Full-field ERGs were recorded under scotopic and photopic conditions. The records were filtered (75-300 Hz) to demonstrate the oscillatory wavelets. The amplitudes and implicit times of the infants' OPs were compared to those in adults and also to amplitudes of the saturated photoreceptor responses.

RESULTS

In infants, the mean OP amplitudes are similar in scotopic and photopic conditions and do not vary significantly with OP number. Infants' OPs are significantly smaller than in adults, with scotopic OPs averaging 19% of that in adults and photopic OPs averaging 47%, whereas the amplitudes of the saturated photoreceptor responses are 43% and 66% of those in adults. Mean interpeak intervals are similar in infants and adults, indicating oscillatory behavior at a frequency of 155 Hz in scotopic conditions and 135 Hz in photopic conditions.

CONCLUSIONS

In young infants, the OPs are relatively immature compared to the photoreceptor responses, with the immaturity of the scotopic responses being more marked than that of the photopic responses.

[Congenital glaucoma and trabeculodysgenesis. Clinical and genetic aspects]

Congenital glaucoma is generally related to an iridocorneal angle malformation, with an obstacle to aqueous humor outflow. This spectrum of diseases can involve the angle, the iris and the cornea. The diagnosis relies on characteristic signs and is confirmed by an examination under general anaesthesia and paraclinical examinations (especially echography). An early diagnosis is essential for beginning surgical treatment. Several filtering surgery techniques with equivalent intraocular pressure results are available, but visual function must be protected in all cases. In many cases, genetic counseling relies on a careful clinical analysis and sometimes on a molecular analysis. A number of ocular and/or general abnormalities can be accompanied by glaucoma in infants and children. They must be screened in case of associated signs, but the existence of these abnormalities leads to suspicion of associated glaucoma.

Multifocal ERG in subjects with a history of retinopathy of prematurity

PURPOSE

Investigate the function of the central retina in subjects with a history of retinopathy of prematurity (ROP).

METHODS

Multifocal electroretinogram (mfERG) responses to a scaled array of 103 hexagons were recorded in subjects, aged 11-23 years (N = 11), with a documented history of mild ROP. The amplitude and implicit time of the components (N(1), P(1), N(2)) of the first order kernel for six concentric rings were compared to those of control subjects (N = 9).

RESULTS

The amplitude of each component varied significantly with eccentricity in both ROP and control subjects and was significantly smaller in the ROP subjects. The discrepancy between ROP and control subjects was greatest for central rings (1-3) and smaller for peripheral rings (4-6). The slopes of the functions summarizing log response density as a function of log eccentricity (degrees visual angle) were significantly shallower in ROP subjects. The implicit time of each component was longer in ROP subjects at all eccentricities.

CONCLUSIONS

ROP associated alterations in neural retinal development may underlie the subtle macular dysfunction disclosed by the mfERG.

Development of the cone ERG in infants

PURPOSE

To assess cone photoreceptor and cone-mediated postreceptoral retinal function in infants.

METHODS

ERG responses to a 1.8-log unit range of long-wavelength flashes on a white, rod-saturating background were recorded in 4-week-old (n = 22) and 10-week-old (n = 28) infants and control adults and children, 8 to 40 years of age (n = 13). A model of the activation of cone phototransduction was fit to the a-waves. Sensitivity (S(CONE)) and saturated-response amplitude (R(CONE)) were calculated. The amplitude and implicit time of the b-wave were examined as a function of stimulus intensity. The cone photoresponse parameters were compared to the rod photoresponse parameters (S(ROD) and R(ROD)) in the same subjects.

RESULTS

S(CONE) and R(CONE) in infants were significantly smaller than in the mature control subjects. The mean S(CONE) was 64% and 68%, and the mean R(CONE) was 63% and 72% in 4- and 10-week-olds, respectively. The mean rod photoresponse parameters were considerably less mature, as the mean S(ROD) was 35% and 46%, and the mean R(ROD) was 39% and 43% of mature values at 4 and 10 weeks. The b-wave stimulus-response functions in the 4- and 10-week-old infants did not show the photopic hill that was characteristic of the children's and adults' photopic b-waves.

CONCLUSIONS

Peripheral cone function is relatively more mature than rod function in young infants. The lack of a photopic hill is hypothesized to result from immaturity in the relative contributions of ON and OFF bipolar cell responses.

First-trimester ultrasound diagnosis in a recurrent case of Walker-Warburg syndrome

We report on two siblings with Walker-Warburg syndrome (WWS) born to a consanguineous couple. In the index case, the second-trimester scan showed ventricular dilatation and we diagnosed WWS after observing retinal detachment at 26 weeks' gestation and lissencephaly by 32 weeks' gestation in addition to hypoplasia of the cerebellar vermis. The second case was first suspected at 12 weeks' gestation, when we observed a 2.8-mm nuchal translucency and an unusually large hindbrain vesicle. By 14 weeks' gestation, the lateral ventricles were clearly enlarged (12-13 mm), at 16 weeks' gestation the vitreous chamber appeared to be hyperechogenic, and by 17 weeks' gestation hydrocephalus was evident. The couple chose to continue the pregnancy, and during the third trimester lissencephaly, major hydrocephalus and polyhydramnios developed. Serial ultrasound examination should be offered to a family with a history of WWS and therefore a 1 in 4 risk of recurrence. In some cases, recurrence can be suspected as early as the first trimester, however the diagnosis cannot be excluded on the basis of normal ultrasound appearance until later in pregnancy.

Congenital nephrosis, mesangial sclerosis, and distinct eye abnormalities with microcoria: an autosomal recessive syndrome

We observed the occurrence of congenital nephrotic syndrome (CNS) and distinct ocular anomalies in two unrelated families. Eleven children from both families presented with a similar course of renal disease starting with nephrotic syndrome and renal failure prenatally or immediately after birth that resulted in death before the age of 2 months. Kidney histopathology showed diffuse mesangial sclerosis (DMS). Clinically obvious eye abnormalities were recognized in six of the eight patients in whom sufficient clinical data were available. Ocular anomalies included enlarged or large appearing corneae in some cases suggesting buphthalmos, and extremely narrow, nonreactive pupils (microcoria). Pathological examination of the eyes of two aborted fetuses revealed a more complex ocular maldevelopment including posterior lenticonus as well as anomalies of cornea and retina. On the basis of these observations and other cases in the literature, we delineate a previously unrecognized distinct entity characterized by congenital nephrotic syndrome, DMS, and eye abnormalities with microcoria as the leading clinical feature. Pedigrees of affected families with parental consanguinity support autosomal recessive inheritance. We propose that this syndrome should be designated microcoria-congenital nephrosis syndrome or Pierson syndrome. Possible overlap with Galloway-Mowat syndrome and relations to other oculo-renal syndromes are discussed.

ULTRASONOGRAPHIC EVALUATION OF PRE- AND POSTNATAL DEVELOPMENT OF THE EYES IN BEAGLES

Transabdominal ultrasonography was performed to visualize the development of intraocular structures of both eyes of four different fetuses in each of two pregnant beagles. Postnatally the development of both eyes of 11 pups was visualized with ultrasonography. Furthermore, biometric measurements of the length of the eye, the depth of cornea, the anterior chamber, the lens (anteroposterior depth and equatorial diameter), and the vitreous body of the fetuses and pups were obtained when these structures could be identified with ultrasonography. In all fetuses the eyes with lens, vitreous body, hyaloid artery, and scleroretinal rim could be clearly identified from day 37 of pregnancy. Postnatally also the cornea, anterior chamber, iris, ciliary body, and optic disc were visible. Biometric measurements revealed, both pre- and postnatally, a continuous growth of the depth of the eye, anterior chamber, lens (anteroposterior depth and equatorial diameter), and vitreous body.

Early sonographic detection of recurrent fetal eye anomalies

OBJECTIVE

To determine the possible association between congenital eye anomaly of a previous child in the family and current congenital eye anomaly.

METHODS

An early transvaginal anomaly scan at 14-16 gestational weeks was used to diagnose fetal eye anomalies in five cases in which at least one previous child in the family had the same congenital eye anomaly.

RESULTS

At least one cataract was detected in four of the five fetuses and bilateral anophthalmia in one. The congenital cataract in one case was part of multiple pterygium syndrome. Both of these extremely rare malformations are commonly associated with other fetal anomalies.

CONCLUSION

Our data suggest that a detailed targeted ultrasound survey with a special focus on the orbital region should be offered at the time of genetic counseling to couples with children with congenital eye anomalies.

Candida (amphotericin-sensitive) lens abscess associated with decreasing arterial blood flow in a very low birth weight preterm infant

In this report, we review the case of a candidal lens abscess in a premature infant girl who was 28 weeks' gestational age at birth. The culture obtained from the lens abscess grew Candida albicans sensitive to amphotericin B but resistant to flucytosine. This case is unique in that the infant developed a fungal lens cataract at 34 weeks' postconceptional age during the last week of a 30-day course of amphotericin B. The embryonic hyaloid artery system, which perfuses the developing lens, regresses between 29 and 32 weeks of gestation; thus, the mechanism for an infection of the lens may be inoculation of the lens by Candida before hyaloid artery system regression, followed by developmental loss of this blood supply, which makes the lens inaccessible to antimicrobial penetration. Candidal endophthalmitis with lens abscess is an uncommon morbidity that requires prompt recognition and surgical intervention for effective management.