The long-term influence of perinatal factors on macular morphology and vessel density in preterm children

BACKGROUND

Increased survival rate of extremely preterm children is associated with a higher risk of retinopathy of prematurity (ROP) and long-term sequelae, which implicate retinal changes.

PURPOSE

To assess an influence of perinatal characteristics on morphology and retinal vascularity of the macula in preterm children.

METHODS

A cohort of 123 preterm children at the age of 10.5 years (IQR: 8.12-12.77) was prospectively assessed. Optical coherence tomography angiography (OCTA) was performed using RTVueXR Avanti. Foveal thickness, parafoveal thickness, size of foveal avascular zone (FAZ), superficial and deep vessel density, central choroidal thickness (CCT) were analyzed. The associations between OCTA results and perinatal factors, including the presence of ROP and therapy requirements were assessed in preterm children.

RESULTS

Significantly smaller FAZ, higher foveal thickness and vessel density were noted in children with ROP, Respiratory Distress Syndrome, Bronchopulmonary Dysplasia, required erythropoietin, transfusion or steroids. Foveal thickness was increased in children with ROP (p < 0.001) and following laser treatment (p < 0.05). Thinner CCT was noted in children with a history of sepsis (p < 0.05) and ROP required treatment (p < 0.05). Pregnancy bleeding was associated with higher superficial foveal vessel density (p < 0.05) and smaller FAZ (p < 0.05).

CONCLUSION

Neonatal factors have a huge impact on retinal development, but the role of prenatal factors should not be neglected in preterm children.

Ocular blood flow in preterm neonates

Retinopathy of prematurity (ROP) is a disorder affecting low birthweight, preterm neonates. In the preterm eye, the retina is not fully developed and neovascularization may occur at the margin between the developed vascular retina and undeveloped avascular retina. Without timely treatment by laser or intravitreal anti-vascular endothelial growth factor (VEGF) therapy, this can lead to tractional retinal detachment and blindness. Visualization of the retina in regular examinations by indirect ophthalmoscopy is hence the current standard of care, but the exams are stressful and interpretation of images is subjective. The upregulation of VEGF in ROP would suggest an increase in ocular blood flow. In this report, we evaluate the potential of ultrafast plane-wave Doppler ultrasound (PWU) to detect increased flow velocities in the orbital vessels supplying the eye in a gentle exam with objective findings. We imaged both eyes of 50 low-birthweight preterm neonates using 18 MHz PWU. Flow velocity in the central retinal artery (CRA) and vein (CRV), and the short posterior ciliary arteries were determined and values at each ROP Stage compared. We found significantly increased velocities in the CRA and CRV in Stage 3 ROP eyes, where intervention would be considered. We compared multivariate models for identifying Stage 3 eyes comprised solely of clinical factors, solely of Doppler parameters, and clinical plus Doppler parameters. The respective models provided areas under their respective ROC curves of 0.760, 0.812, and 0.904. PWU Doppler represents a gentle, objective means for identifying neonates at risk for ROP that could complement ophthalmoscopy.

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.

Evaluation of retinal vascularization in retinopathy of prematurity regressed after intravitreal ranibizumab monotherapy or without treatment based on fluorescein angiography

To investigate the fluorescein angiography (FA) findings and compare the extent of retinal vascularization in retinopathy of prematurity (ROP), recovered after intravitreal ranibizumab (IVR) monotherapy and those regressed spontaneously. Infants with a history of ROP who underwent FA between April 2018 and November 2021 were retrospectively included. The patients were divided into two groups based on whether they had received IVR (IVR group) or had ROP that regressed spontaneously without treatment (untreated group). The differences between the two groups in zone II ROP were also compared, to equalize the subgroups as much as possible in terms of disease severity. FA findings were recorded. The extent of vascularization was measured by the ratio of the distance from the center of the disk to the border of the vascularized zone (DB) and the distance from the center of the disk to the center of the fovea (DF). The width of the persistent avascular retina (PAR) was counted by disc diameters (DD). One hundred and ten eyes of 55 infants were included in the IVR group and 76 eyes of 38 babies in the untreated group. The ratio of abnormal shape of vessels was significantly higher in the IVR group than in the untreated group (50.9% vs. 35.5%; P = 0.038), while the linear choroidal filling pattern, tortuosity of vessels over the posterior pole, dye leakage, anomalous branching of vessels, circumferential vessels, arteriovenous shunt, abnormal capillary bed, and macular abnormalities were similarly. There was a smaller temporal DB/DF ratio (4.48 vs. 4.63; P = 0.003) and greater PAR (2.63 vs. 1.76; P < 0.001) in the IVR group compared to the untreated group. In zone II ROP, the progression of retinal vascularization was significantly larger in the IVR group than that in the untreated group (P = 0.003), while no statistical differences were observed in FA features, the DB/DF ratio, and PAR between the two subgroups. The residual vascular abnormalities and PAR may be common results of ROP regression. The DB/DF ratio of 4.0 temporally and 3.3 nasally could be used as the preliminary indicators for safe retinal vascularization in the completion of ROP regression.

ROP-GAN: an image synthesis method for retinopathy of prematurity based on generative adversarial network

Objective. Training data with annotations are scarce in the intelligent diagnosis of retinopathy of prematurity (ROP), and existing typical data augmentation methods cannot generate data with a high degree of diversity. In order to increase the sample size and the generalization ability of the classification model, we propose a method called ROP-GAN for image synthesis of ROP based on a generative adversarial network.Approach. To generate a binary vascular network from color fundus images, we first design an image segmentation model based on U2-Net that can extract multi-scale features without reducing the resolution of the feature map. The vascular network is then fed into an adversarial autoencoder for reconstruction, which increases the diversity of the vascular network diagram. Then, we design an ROP image synthesis algorithm based on a generative adversarial network, in which paired color fundus images and binarized vascular networks are input into the image generation model to train the generator and discriminator, and attention mechanism modules are added to the generator to improve its detail synthesis ability.Main results. Qualitative and quantitative evaluation indicators are applied to evaluate the proposed method, and experiments demonstrate that the proposed method is superior to the existing ROP image synthesis methods, as it can synthesize realistic ROP fundus images.Significance. Our method effectively alleviates the problem of data imbalance in ROP intelligent diagnosis, contributes to the implementation of ROP staging tasks, and lays the foundation for further research. In addition to classification tasks, our synthesized images can facilitate tasks that require large amounts of medical data, such as detecting lesions and segmenting medical images.

Ocular Pigmentation Impact on Retinal Versus Choroidal Optical Coherence Tomography Imaging in Preterm Infants

Purpose

To evaluate the association of fundus pigmentation with the visibility of retinal versus choroidal layers on optical coherence tomography (OCT) in preterm infants.

Methods

For infants enrolled in BabySTEPS, ophthalmologists recorded fundus pigmentation (blond, medium, or dark) at the first retinopathy of prematurity (ROP) examination. Bedside OCT imaging was performed at each examination, and a masked grader evaluated all OCT scans from both eyes of each infant for visibility (yes/no) of all retinal layers and of the chorio-scleral junction (CSJ). Multivariable logistic regression was used to assess associations between fundus pigmentation and visibility of all retinal layers and CSJ, controlling for potential confounders (i.e., birth weight, gestational age, sex, OCT system, pupil size, and postmenstrual age at imaging).

Results

Among 114 infants (mean birth weight, 943 grams; mean gestational age, 27.6 weeks), 43 infants (38%) had blond, 56 infants (49%) had medium, and 15 infants (13%) had dark fundus pigmentation. Of 1042 scans, all retinal layers were visible in 977 (94%) and CSJ in 895 (86%). Pigmentation was not associated with retinal layer visibility (P = 0.49), but medium and dark pigmentation were associated with decreased CSJ visibility (medium: odds ratio [OR] = 0.34, P = 0.001; dark: OR = 0.24, P = 0.009). For infants with dark pigmentation, retinal layer visibility increased (OR = 1.87 per week; P ≤ 0.001) and CSJ visibility decreased (OR = 0.78 per week; P = 0.01) with increasing age.

Conclusions

Although fundus pigmentation was not associated with the visibility of all retinal layers on OCT, darker pigmentation decreased CSJ visibility, and this effect increased with age.

Translational Relevance

The ability of bedside OCT to capture retinal layer microanatomy in preterm infants, regardless of fundus pigmentation, may represent an advantage over fundus photography for ROP telemedicine.

Multivariate Models to Diagnose Early Referral-Warranted Retinopathy of Prematurity With Handheld Optical Coherence Tomography

Purpose

The purpose of this study was to create multivariate models predicting early referral-warranted retinopathy of prematurity (ROP) using non-contact handheld spectral-domain optical coherence tomography (OCT) and demographic data.

Methods

Between July 2015 and February 2018, infants ≤1500 grams birth weight or ≤30 weeks gestational age from 2 academic neonatal intensive care units were eligible for this study. Infants were excluded if they were too unstable to participate in ophthalmologic examination (2), had inadequate image quality (20), or received prior ROP treatment (2). Multivariate models were created using demographic variables and imaging findings to identify early referral-warranted ROP (referral-warranted ROP and/or pre-plus disease) by routine indirect ophthalmoscopy.

Results

A total of 167 imaging sessions of 71 infants (45% male infants, gestational age 28.2+/-2.8 weeks, and birth weight 995.6+/-292.0 grams) were included. Twelve of 71 infants (17%) developed early referral-warranted ROP. The area under the receiver operating characteristic curve (AUC) was 0.94 for the generalized linear mixed model (sensitivity = 95.5% and specificity = 80.7%) and 0.83 for the machine learning model (sensitivity = 91.7% and specificity = 77.8%). The strongest variables in both models were birth weight, image-based Vitreous Opacity Ratio (an estimate of opacity density), vessel elevation, and hyporeflective vessels. A model using only birth weight and gestational age yielded an AUC of 0.68 (sensitivity = 77.3% and specificity = 63.4%), and a model using only imaging biomarkers yielded 0.88 (sensitivity = 81.8% and specificity = 84.8%).

Conclusions

A generalized linear mixed model containing handheld OCT biomarkers can identify early referral-warranted ROP. Machine learning produced a less optimal model.

Translational Relevance

With further validation, this work may lead to a better-tolerated ROP screening tool.

MHANet: A hybrid attention mechanism for retinal diseases classification

With the increase of patients with retinopathy, retinopathy recognition has become a research hotspot. In this article, we describe the etiology and symptoms of three kinds of retinal diseases, including drusen(DRUSEN), choroidal neovascularization(CNV) and diabetic macular edema(DME). In addition, we also propose a hybrid attention mechanism to classify and recognize different types of retinopathy images. In particular, the hybrid attention mechanism proposed in this paper includes parallel spatial attention mechanism and channel attention mechanism. It can extract the key features in the channel dimension and spatial dimension of retinopathy images, and reduce the negative impact of background information on classification results. The experimental results show that the hybrid attention mechanism proposed in this paper can better assist the network to focus on extracting thr fetures of the retinopathy area and enhance the adaptability to the differences of different data sets. Finally, the hybrid attention mechanism achieved 96.5% and 99.76% classification accuracy on two public OCT data sets of retinopathy, respectively.

Automatic Staging for Retinopathy of Prematurity With Deep Feature Fusion and Ordinal Classification Strategy

Retinopathy of prematurity (ROP) is a retinal disease which frequently occurs in premature babies with low birth weight and is considered as one of the major preventable causes of childhood blindness. Although automatic and semi-automatic diagnoses of ROP based on fundus image have been researched, most of the previous studies focused on plus disease detection and ROP screening. There are few studies focusing on ROP staging, which is important for the severity evaluation of the disease. To be consistent with clinical 5-level ROP staging, a novel and effective deep neural network based 5-level ROP staging network is proposed, which consists of multi-stream based parallel feature extractor, concatenation based deep feature fuser and clinical practice based ordinal classifier. First, the three-stream parallel framework including ResNet18, DenseNet121 and EfficientNetB2 is proposed as the feature extractor, which can extract rich and diverse high-level features. Second, the features from three streams are deeply fused by concatenation and convolution to generate a more effective and comprehensive feature. Finally, in the classification stage, an ordinal classification strategy is adopted, which can effectively improve the ROP staging performance. The proposed ROP staging network was evaluated with per-image and per-examination strategies. For per-image ROP staging, the proposed method was evaluated on 635 retinal fundus images from 196 examinations, including 303 Normal, 26 Stage 1, 127 Stage 2, 106 Stage 3, 61 Stage 4 and 12 Stage 5, which achieves 0.9055 for weighted recall, 0.9092 for weighted precision, 0.9043 for weighted F1 score, 0.9827 for accuracy with 1 (ACC1) and 0.9786 for Kappa, respectively. While for per-examination ROP staging, 1173 examinations with a 4-fold cross validation strategy were used to evaluate the effectiveness of the proposed method, which prove the validity and advantage of the proposed method.

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.

Comparison of wide field imaging by nurses with indirect ophthalmoscopy by ophthalmologists for retinopathy of prematurity: a diagnostic accuracy study

OBJECTIVES

Retinopathy of prematurity (ROP) is a vasoproliferative disease of the preterm retina with the potential to cause irreversible blindness. Timely screening and treatment of ROP are critical. Neonatal nurses trained in wide field digital retinal photography (WFDRP) for screening may provide a safe and effective strategy to reduce the burden of ophthalmologists in performing binocular indirect ophthalmoscopy (BIO). The objective of the study was to determine the diagnostic accuracy of WFDRP in the diagnosis of referral warranting ROP (RWROP).

DESIGN

Prospective diagnostic accuracy study.

SETTING

A tertiary neonatal intensive care unit in Perth, Western Australia.

PARTICIPANTS

Preterm infants who fulfilled the Australian ROP screening criteria (gestational age (GA) <31 weeks, birth weight (BW) <1250 g).

INTERVENTION

Sets of 5-6 images per eye (index test) were obtained within 24-48 hours prior to or after the BIO (reference standard), and uploaded onto a secured server. A wide field digital camera (RetCam, Natus, Pleasanton, California, USA) was used for imaging. A paediatric ophthalmologist performed the BIO. The ophthalmologists performing BIO versus reporting the images were masked to each other's findings.

PRIMARY OUTCOME

The area under the receiver operating characteristic (ROC) curve was used as a measure of accuracy of WFDRP to diagnose RWROP.

RESULTS

A total of 85 infants (mean BW; 973.43 g, mean GA; 29 weeks) underwent a median of two sessions of WFDRP. There were 188 episodes of screening with an average of five images per eye. WFDRP identified RWROP in 7.4% (14/188 sessions) of examinations. In one infant, BIO showed bilateral plus disease and WFDRP did not pick up the plus disease. WFDRP image interpretation had a sensitivity of 80%, specificity of 94.5% for the detection of RWROP. The 'area under the ROC curve' was 88% when adjusted for covariates.

CONCLUSIONS

WFDRP by neonatal nurses was feasible and effective for diagnosing RWROP in our set up.

TRIAL REGISTRATION NUMBER

ACTRN12616001386426.

Retinopathy of Prematurity and Bronchopulmonary Dysplasia are Independent Antecedents of Cortical Maturational Abnormalities in Very Preterm Infants

Very preterm (VPT) infants are at high-risk for neurodevelopmental impairments, however there are few validated biomarkers at term-equivalent age that accurately measure abnormal brain development and predict future impairments. Our objectives were to quantify and contrast cortical features between full-term and VPT infants at term and to associate two key antecedent risk factors, bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP), with cortical maturational changes in VPT infants. We prospectively enrolled a population-based cohort of 110 VPT infants (gestational age ≤31 weeks) and 51 healthy full-term infants (gestational age 38-42 weeks). Structural brain MRI was performed at term. 94 VPT infants and 46 full-term infants with high-quality T2-weighted MRI were analyzed. As compared to full-term infants, VPT infants exhibited significant global cortical maturational abnormalities, including reduced surface area (-5.9%) and gyrification (-6.7%) and increased curvature (5.9%). In multivariable regression controlled for important covariates, BPD was significantly negatively correlated with lobar and global cortical surface area and ROP was significantly negatively correlated with lobar and global sulcal depth in VPT infants. Our cohort of VPT infants exhibited widespread cortical maturation abnormalities by term-equivalent age that were in part anteceded by two of the most potent neonatal diseases, BPD and ROP.

Refractive outcomes comparing primary laser to primary bevacizumab with delayed laser for type 1 ROP

PURPOSE

To compare the refractive outcomes of intravitreal bevacizumab (IVB) and delayed peripheral retinal photocoagulation (PRP) with primary PRP in infants treated for posterior type 1 ROP.

METHODS

The medical records of 87 infants at a tertiary referral center treated for posterior type 1 ROP between 2006 and 2016 were reviewed retrospectively. Consecutive infants received primary PRP before and primary IVB after a change in treatment practice implemented in early 2011. In most cases primary IVB was supplemented with prophylactic laser treatment after 60 weeks' PMA (IVB-PRP). The main outcome was spherical equivalent (SE) in diopters, determined by cycloplegic refraction between 2 and 4 years. Infants treated with IVB-PRP were also compared to the those who received only IVB as monotherapy.

RESULTS

The final analysis included 34 eyes of 19 infants in the primary PRP group and 40 eyes of 21 infants in the IVB-PRP group. Mean SE was -7.4 ± 5.2 D in the primary PRP group and -0.16 ± 2.2 D in the IVB-PRP group (P < 0.001). This relationship persisted after stratification by zone of ROP and the presence of aggressive posterior ROP. There was no statistically significant difference in mean SE between the IVB-PRP group and the 8 eyes of 4 infants who received IVB as monotherapy. Of 46 infants who received primary IVB, 37 completed an examination under anesthesia after 60 weeks' PMA. In these patients, 70% of eyes showed peripheral vascular leakage on fluorescein angiography.

CONCLUSIONS

In our study cohort, infants treated with IVB-PRP were significantly less myopic than those treated with primary PRP. Delayed laser after 60 weeks' PMA, in hopes of reducing the risk of late reactivation with retinal detachment, did not negate the refractive benefits of primary IVB.

Imaging in Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a leading cause of preventable childhood blindness worldwide. Barriers to ROP screening and difficulties with subsequent evaluation and management include poor access to care, lack of physicians trained in ROP, and issues with objective documentation. Digital retinal imaging can help address these barriers and improve our knowledge of the pathophysiology of the disease. Advancements in technology have led to new, non-mydriatic and mydriatic cameras with wider fields of view as well as devices that can simultaneously incorporate fluorescein angiography, optical coherence tomography (OCT), and OCT angiography. Image analysis in ROP is also being employed through smartphones and computer-based software. Telemedicine programs in the United States and worldwide have utilized imaging to extend ROP screening to infants in remote areas and have shown that digital retinal imaging can be reliable, accurate, and cost-effective. In addition, tele-education programs are also using digital retinal images to increase the number of healthcare providers trained in ROP. Although indirect ophthalmoscopy is still an important skill for screening, digital retinal imaging holds promise for more widespread screening and management of ROP.

Automated Analysis for Retinopathy of Prematurity by Deep Neural Networks

Retinopathy of Prematurity (ROP) is a retinal vasproliferative disorder disease principally observed in infants born prematurely with low birth weight. ROP is an important cause of childhood blindness. Although automatic or semi-automatic diagnosis of ROP has been conducted, most previous studies have focused on "plus" disease, which is indicated by abnormalities of retinal vasculature. Few studies have reported methods for identifying the "stage" of the ROP disease. Deep neural networks have achieved impressive results in many computer vision and medical image analysis problems, raising expectations that it might be a promising tool in the automatic diagnosis of ROP. In this paper, convolutional neural networks with a novel architecture are proposed to recognize the existence and severity of ROP disease per-examination. The severity of ROP is divided into mild and severe cases according to the disease progression. The proposed architecture consists of two sub-networks connected by a feature aggregate operator. The first sub-network is designed to extract high-level features from images of the fundus. These features from different images in an examination are fused by the aggregate operator, then used as the input for the second sub-network to predict its class. A large data set imaged by RetCam 3 is used to train and evaluate the model. The high classification accuracy in the experiment demonstrates the effectiveness of the proposed architecture for recognizing the ROP disease.

Deep Learning for Image Quality Assessment of Fundus Images in Retinopathy of Prematurity

Accurate image-based medical diagnosis relies upon adequate image quality and clarity. This has important implications for clinical diagnosis, and for emerging methods such as telemedicine and computer-based image analysis. In this study, we trained a convolutional neural network (CNN) to automatically assess the quality of retinal fundus images in a representative ophthalmic disease, retinopathy of prematurity (ROP). 6,043 wide-angle fundus images were collected from preterm infants during routine ROP screening examinations. Images were assessed by clinical experts for quality regarding ability to diagnose ROP accurately, and were labeled "acceptable" or "not acceptable." The CNN training, validation and test sets consisted of 2,770 images, 200 images, and 3,073 images, respectively. Test set accuracy was 89.1%, with area under the receiver operating curve equal to 0.964, and area under the precision-recall curve equal to 0.966. Taken together, our CNN shows promise as a useful prescreening method for telemedicine and computer-based image analysis applications. We feel this methodology is generalizable to all clinical domains involving image-based diagnosis.

Non-contact retinal imaging compared to indirect ophthalmoscopy for retinopathy of prematurity screening: infant safety profile

OBJECTIVE

Most retinopathy of prematurity screening involves an ophthalmologist performing indirect ophthalmoscopy, which can be stressful to infants. The purpose of this study is to evaluate the safety profile (using cardiopulmonary events as an indicator) of imaging infants with a non-contact retinal camera compared to examining them using indirect ophthalmoscopy.

STUDY DESIGN

Prospective cohort study of 99 infants at a community hospital who were examined using indirect ophthalmoscopy and imaged using a non-contact retinal camera for retinopathy of prematurity. We evaluated the difference in the occurrence of safety events (i.e., clinically significant bradycardia, tachycardia, oxygen desaturation, or apnea) following the clinical examination versus retinal imaging.

RESULT

Safety events occurred after 0.8% (n = 1) of imaging sessions and 5.8% (n = 18) of clinical examinations (mean difference = -0.055 (p = 0.015), favoring imaging).

CONCLUSION

Retinal imaging with a non-contact camera was well tolerated and less stressful to infants compared to indirect ophthalmoscopy by an ophthalmologist.

Development of a scale for grading pre-plus and plus disease using retinal images: A pilot study

When screening infants for retinopathy of prematurity, evaluating posterior pole vascular characteristics (ie, the presence or absence of pre-plus or plus disease) is subjective and prone to error. ROPtool, a semiautomated computer program, measures retinal vessel tortuosity and dilation. In this pilot study, we created an abbreviated pictorial scale of varying vascular tortuosity and dilation based on expert perception of vascular characteristics. We used ROPtool to evaluate the experts' ability to arrange these images in order of increasing vascular tortuosity and dilation. ROPtool values confirmed successful arrangement of images in order of increasing vascular tortuosity and dilation. This pictorial scale could serve as a reference to decrease subjectivity when diagnosing pre-plus or plus disease.

Macular Structures, Optical Components, and Visual Acuity in Preschool Children after Intravitreal Bevacizumab or Laser Treatment

PURPOSE

To investigate the macular structures, optical components, and visual acuity in preschool-aged children with a history of type I retinopathy of prematurity who underwent either intravitreal bevacizumab (IVB), laser, or a combination of treatments.

DESIGN

Comparative interventional case series.

METHODS

Setting: A referred medical center in Taiwan.

STUDY POPULATION

Eighty eyes from 42 patients (33 IVB-treated eyes from 17 children, 24 laser-treated eyes from 13 children, and 23 laser + IVB-treated eyes from 12 children).

OBSERVATION PROCEDURE

Spectral-domain optical coherence tomography.

MAIN OUTCOME MEASURES

The retinal thickness in the foveal area and the associated morphologic changes in foveal depression.

RESULTS

Compared with the laser-treated and laser + IVB-treated eyes, the IVB-treated eyes had less myopia and deeper anterior chamber depths but presented similar axial lengths and corneal curvatures (P = .001, P = .002, P = .95, and P = .16, respectively). The IVB-treated eyes had significantly thinner foveal, parafoveal, and perifoveal retinal thicknesses (P < .01 for all) and a higher incidence of foveal depression than the laser- or laser + IVB-treated eyes. The macular and subfoveal choroidal thicknesses did not differ among the groups (P = .21 and P = .63, respectively). Moreover, compared with the eyes treated with laser or laser + IVB, the IVB-treated eyes had better uncorrected visual acuity, although a significant difference was not observed in best-corrected visual acuity (P = .008 and P = .29, respectively).

CONCLUSIONS

Compared with laser therapy, IVB-treated eyes were associated with deeper anterior chamber depths and thinner foveal, parafoveal, and perifoveal thicknesses. Moreover, these IVB-treated eyes had fewer refractive errors and better uncorrected visual acuity.

Determinants of Indices of Cerebral Volume in Former Very Premature Infants at Term Equivalent Age

Conventional magnetic resonance imaging (MRI) at term equivalent age (TEA) is suggested to be a reliable tool to predict the outcome of very premature infants. The objective of this study was to determine simple reproducible MRI indices, in premature infants and to analyze their neonatal determinants at TEA. A cohort of infants born before 32 weeks gestational age (GA) underwent a MRI at TEA in our center. Two axial images (T2 weighted), were chosen to realize nine measures. We defined 4 linear indices (MAfhlv: thickness of lateral ventricle; CSI: cortex-skull index; VCI: ventricular-cortex index; BOI: bi occipital index) and 1 surface index (VS.A: volume slice area). Perinatal data were recorded. Sixty-nine infants had a GA (median (interquartile range)) of 30.0 weeks GA (27.0; 30.0) and a birth weight of 1240 grams (986; 1477). MRI was done at 41.0 (40.0; 42.0) weeks post menstrual age (PMA). The inter-investigator reproducibility was good. Twenty one MRI (30.5%) were quoted abnormal. We observed an association with retinopathy of prematurity (OR [95CI] = 4.205 [1.231-14.368]; p = 0.017), surgery for patent ductus arteriosus (OR = 4.688 [1.01-21.89]; p = 0.036), early onset infection (OR = 4.688 [1.004-21.889]; p = 0.036) and neonatal treatment by cefotaxime (OR = 3.222 [1.093-9.497]; p = 0.03). There was a difference for VCI between normal and abnormal MRI (0.412 (0.388; 0.429) vs. 0.432 (0.418; 0.449); p = 0,019); BOI was higher when fossa posterior lesions were observed; VS.A seems to be the best surrogate for cerebral volume, 80% of VS.As' variance being explained by a multiple linear regression model including 7 variables (head circumference at birth and at TEA, PMA, dopamine, ibuprofen treatment, blood and platelets transfusions). These indices, easily and rapidly achievable, seem to be useful but need to be validated in a large population to allow generalization for diagnosis and follow-up of former premature infants.

Comprehensive Retinal Image Analysis for Aggressive Posterior Retinopathy of Prematurity

Computer aided analysis plays a nontrivial role in assisting the diagnosis of various eye pathologies. In this paper, we propose a framework to help diagnose the presence of Aggressive Posterior Retinopathy Of Prematurity (APROP), a pathology that is characterised by rapid onset and increased tortuosity of blood vessels close to the optic disc (OD). We quantify vessel characteristics that are of clinical relevance to APROP such as tortuosity and the extent of branching i.e., vessel segment count in the defined diagnostic region. We have adapted three vessel segmentation techniques: matched filter response, scale space theory and morphology with local entropy based thresholding. The proposed feature set equips us to build a linear discriminant classifier to discriminate APROP images from clinically healthy images. We have studied 36 images from 21 APROP subjects against a control group of 15 clinically healthy age matched infants. All subjects are age matched ranging from 33−40 weeks of post menstrual age. Experimental results show that we attain 100% recall and 95.45% precision, when the vessel network obtained from morphology is used for feature extraction.

[Telemedicine correlation in retinopathy of prematurity between experts and non-expert observers]

OBJECTIVE

To study the correlation between expert and non-expert observers in the reporting images for the diagnosis of retinopathy of prematurity (ROP) in a telemedicine setting.

METHODS

A cross-sectional, multicenter study, consisting of 25 sets of images of patients screened for ROP. They were evaluated by two experts in ROP and 1 non-expert and classified according to telemedicine classification, zone, stage, plus disease and Ells referral criteria. The telemedicine classification was: no ROP, mild ROP, type 2 ROP, or ROP that requires treatment. Ells referral criteria is defined as the presence at least one of the following: ROP in zone I, Stage 3 in zone I or II, or plus+ For statistical analysis, SPSS 16.0 was used. For correlation, Kappa value was performed.

RESULTS

There was a high correlation between observers for the assessment of ROP stage (0.75; 0.54-0.88) plus disease (0.85; 0.71-0.92), and Ells criteria (0.89; 0.83-1.0). However, inter-observer values were low for zone (0.41; 0.27-0.54) and telemedicine classification (0.43; 0.33-0.6).

CONCLUSIONS

When evaluating telemedicine images by examiners with different levels of expertise in ROP, the Ells criteria gave the best correlation. In addition, stage of disease and plus disease have good correlation among observers. In contrast, the correlation between observers was low for zone and telemedicine classification.

Ultrasonographic findings in eyes with retinal detachments secondary to retinopathy of prematurity

PURPOSE

To describe ultrasonographic findings of stages 4 and 5 retinopathy of prematurity.

PATIENTS AND METHODS

Ocular ultrasonography was performed using a 10-MHz transducer. Forty-four patients (88 eyes) with stages 4 and 5 retinopathy of prematurity were evaluated. Twenty-five patients were female. The mean age was 8.4 months (standard deviation, +/- 4.9).

RESULTS

Retinal detachment configurations were as follows: 31% closed posterior and open anterior, 19% closed posterior and anterior, 14% open posterior and anterior, and 14% open posterior and closed anterior. Additional findings included vitreous opacities (14%), proliferative vitreoretinopathy (22%), subretinal opacities (24%), choroidal thickening (18%), and reduced axial diameter (75%).

CONCLUSIONS

Ultrasonographic evaluation in eyes with advanced retinopathy of prematurity guides surgical indication, management, and visual prognosis.

TENT-SHAPED RETINAL DETACHMENTS IN RETINOPATHY OF PREMATURITY

BACKGROUND

Most retinal detachments associated with retinopathy of prematurity (ROP) are radial, segmental, or circumferential with cicatricial extraretinal fibrovascular proliferation (EFP) at the apex of the detachment. This report describes peculiar tent-shaped retinal detachments that developed among eyes with ROP.

METHODS

An observational case series consisting of 9 patients and 13 eyes with tent-shaped retinal detachments. Their morphology, clinical baseline, surgical course, and final retinal status were extracted from medical records.

RESULTS

Eight had simple tent-shaped retinal detachments, three had a double tent-shaped retinal detachment, one had a chevron-based retinal detachment, and one had a star-shaped retinal detachment. Each case had a disk based stalk that extended to the apex of the traction retinal detachment and continued anteriorly; 12 stalks inserted in the retrolental space and 1 terminated in the mid vitreous. Six eyes were stage 4A, two eyes were stage 4B, and five eyes were stage 5. Vitrectomy surgery was performed on 11 eyes. Surgery resulted in retinal attachment in nine eyes, and two retinas remained detached.

CONCLUSION

Tent-shaped retinal detachments are seen in patients with ROP. A stalk should be sought in evaluation of these eyes. Vitreous surgery focused on relieving this traction is often successful.

Evaluation of blood flow in the ophthalmic artery and central retinal artery in children with retinopathy of prematurity

PURPOSE

To evaluate blood flow parameters in the ophthalmic artery and central retinal artery in children with retinopathy of prematurity (ROP).

MATERIAL AND METHODS

The study comprised 57 premature children born between 24 and 33 weeks of gestation, with birth weight from 600 g to 1660 g, including 42 preterm children with retinopathy in stage 1, 2, 3 and 3 "plus" and 15 preterm children without retinopathy. Color Doppler ultrasonography (USG-CD) was used to measure in the studied vessels maximal systolic velocity (Vmax), end-diastolic velocity (Vmin) and resistance index (RI).

RESULTS

Statistically significantly (p < 0.05) higher values of Vmax were seen in the ophthalmic artery and central retinal artery in preterm children with retinopathy in stage 2 and 3, as compared with other children. In preterms with dilation and tortuosity of posterior blood vessels in stage 3 "plus" ROP Vmax in both studied vessels was lower and was comparable to that in stage 1 ROP and in children without retinopathy. RI in the ophthalmic artery in children with ROP in stage 2 and 3 was statistically significantly higher (p < 0.05) from its values seen in other groups, and for the central retinal artery RI did not differ statistically significantly.

CONCLUSIONS

The conducted USG-CD measurements revealed that in children with retinopathy of prematurity haemodynamic parameters of blood flow in the ophthalmic artery and central retinal artery differ in relation to disease stage of advancement, and in relation to the status of blood vessels in the eye fundus. The clinical implications of these results, however, need to be confirmed in long term studies, in order to determine the sensitivity, specificity and repeatability of this method, as well as to establish the diagnostic standards.

Is there a role for high-frequency ultrasonography in clinical staging of retinopathy of prematurity?

PURPOSE

To compare 20-MHz ultrasonography with ophthalmoscopy in the staging of retinopathy of prematurity (ROP).

METHODS

We used a handheld 20-MHz ultrasound system to examine 38 eyes of 19 neonates who had an indirect ophthalmoscopic examination (diagnosis masked) within 48 hours prior to ultrasonography. Determination of ROP by indirect ophthalmoscopy was compared with independent identification of ultrasonic features indicative of ROP stages.

RESULTS

In masked cases, ultrasonography correctly identified 13 of 18 (72.2% sensitivity) eyes with zone 2, stage 2 ROP or worse and 19 of 20 (95.0% specificity) normal eyes (zone 2, stage 1 ROP or better) (chi-square, 18.4; P < .001).

CONCLUSION

In the neonatal nursery, a 20-MHz handheld ultrasound system may be an effective screening tool to initially identify ROP for further ophthalmoscopic evaluation and management.

[The use of ultrasonographic techniques for the diagnosis of retinopathy of prematurity]

INTRODUCTION

Ultrasonographic techniques are commonly used for the imaging of various tissue structures and organs, including the eyeball and orbit. The non-invasive ultrasound imaging is safe for the patient and may be repeated after a short time unlike in the case of other radiological techniques. In pediatric ophthalmology, ultrasonography plays a major role as an auxiliary examination for the diagnosis of various intraocular diseases, pathologies of the retina and choroid, and retrobulbar conditions. Ultrasonography is of major importance in diagnosing eye disorders associated with opacity preventing visual inspection of the posterior eye segment.

METHODS

Among ultrasonographic techniques in pediatric ophthalmology the most frequently used are B-scan, A-scan, and Doppler ultrasonography. Because of the resolution of ultrasonographic methods in comparison to radiological techniques, they play an important role in monitoring the dynamics of pathological processes in retinopathy of prematurity (ROP). Other radiological methods such as CT, MRI or subtractive angiography do not offer a detailed view of retinal attachment or vitreo-retinal proliferation.

CONCLUSION

Ultrasonography as an auxiliary examination at subsequent stages of ROP helps to document the changes and in case of corneal opacity connected with progression of vitreo-retinal abnormalities is the basis for the diagnosis.

High resolution ultrasonography in eyes with angle-closure glaucoma associated with the cicatricial stage of retinopathy of prematurity

BACKGROUND

Angle-closure glaucoma in children at the cicatricial stage of retinopathy of prematurity (ROP) has been thought to be caused by the anterior displacement of the lens-iris diaphragm resulting from contraction of a retrolental fibrous membrane. Other possible mechanisms include pupillary block and ciliary block.

CASES

Three patients (three eyes) at the cicatricial stage of ROP with angle-closure glaucoma were examined by high-resolution ultrasonography before and after peripheral iridectomy.

OBSERVATIONS

High-resolution ultrasonography preoperatively showed that the angle was closed. A retrolental fibrous membrane was attached behind the lens. After the iridectomy, ultrasonography showed an open angle, and the intraocular pressure was normal.

CONCLUSIONS

The angle closure in our three patients was caused mainly by a pupillary block and could be treated by peripheral iridectomy.

Comparison of ultrasonic and ophthalmoscopic evaluation of retinopathy of prematurity

PURPOSE

Screening for detection of retinopathy of prematurity (ROP) currently is limited to indirect ophthalmoscopy, which requires considerable examiner skill and experience. We investigated whether conventional 10 MHz B-scan ultrasonography could document the clinical stages of ROP as accurately as indirect ophthalmoscopy.

METHODS

Thirty-four eyes of 18 neonates were examined by masked, independent observers with indirect ophthalmoscopy and digitally recorded 10-MHz B-scan ultrasonography. After pupil dilation and lid speculum placement, the retinologist recorded the stage of retinopathy with a retinal drawing. The ultrasonographer, without use of papillary mydriatics or lid speculum, determined the presence or absence of a ridge or tractional elements, if present on the ridge.

RESULTS

Ultrasound grade correlated with clinical grade (R = .79, P < .001). However, nine eyes were overdiagnosed by one stage, and one eye, in which a peripheral detachment was mistaken for an artifact, was underdiagnosed.

CONCLUSIONS

Ten-megahertz ultrasonography offers the potential of imaging and detecting the clinical stages of ROP; the use of higher ultrasound frequencies, now becoming commercially available, is likely to enhance diagnostic accuracy. Care must be taken to distinguish between artifact and true anatomical structures in noncontact ultrasound examinations. Neonates with suspected ROP could be screened with B-scan ultrasonography by neonatal personnel without pupillary dilatation or lid speculum, thus eliminating potential morbidity, and clinically significant cases of ROP then could be referred to the retinologist.

[Ultrasonography of intraocular pathology in a pediatric oncology clinic]

Forty-seven children with the intraocular acoustic effect of "plus-tissue", which was preconditioned by retinoblastoma, Coats' disease, retinopathy of the scarring stage in premature newborns and differentetiology fibroses of the vitreous body, underwent ultrasound examinations, including color Doppler mapping and pulse Doppler-graphy, for the purpose of promoting the differentiated diagnostics. Determinative ultrasonographic criteria were specified for each of the mentioned pathology states; a special significance of Doppler tools is pointed out in detecting a nature of the neovascular network, in identifying a.hyaloidea present in premature newborns and also present in retinal detachment with profound vitreous changes.

Characterization of changes in blood vessel width and tortuosity in retinopathy of prematurity using image analysis

Many retinal diseases are characterised by changes to retinal vessels. For example, a common condition associated with retinopathy of prematurity (ROP) is so-called plus disease, characterised by increased vascular dilation and tortuosity. This paper presents a general technique for segmenting out vascular structures in retinal images, and characterising the segmented blood vessels. The segmentation technique consists of several steps. Morphological preprocessing is used to emphasise linear structures such as vessels. A second derivative operator is used to further emphasise thin vascular structures, and is followed by a final morphological filtering stage. Thresholding of this image is used to provide a segmented vascular mask. Skeletonisation of this mask allows identification of points in the image where vessels cross (bifurcations and crossing points) and allows the width and tortuosity of vessel segments to be calculated. The accuracy of the segmentation stage is quite dependent on the parameters used, particularly at the thresholding stage. However, reliable measurements of vessel width and tortuosity were shown using test images. Using these tools, a set of images drawn from 23 subjects being screened for the presence of threshold ROP disease is considered. Of these subjects, 11 subsequently required treatment for ROP, 9 had no evidence of ROP, and 3 had spontaneously regressed ROP. The average vessel width and tortuosity for the treated subjects was 96.8 microm and 1.125. The corresponding figures for the non-treated cohort were 86.4 microm and 1.097. These differences were statistically significant at the 99% and 95% significance level, respectively. Subjects who progressed to threshold disease during the course of screening showed an average increase in vessel width of 9.6 microm and in tortuosity of +0.008. Only the change in width was statistically significant. Applying a simple retrospective screening paradigm based solely on vessel width and tortuosity yields a screening test with a sensitivity and specificity of 82% and 75%. Factors confounding a more accurate test include poor image quality, inaccuracies in vessel segmentation, inaccuracies in measurement of vessel width and tortuosity, and limitations inherent in screening based solely on examination of the posterior pole.

[Clinical informative value of new methods of ultrasonic examination in the differential diagnosis of various forms of congenital diseases of the eyes in children]

Clinical informative value of computer echography for the differential diagnosis of severe intrauterine uveitis (68 children, 96 eyes), retinopathy neonatorum (37 children, 74 eyes), Coats' retinitis (35 children, 35 eyes), and retinoblastoma (17 children, 26 eyes) was studied in a group of 157 children (231 eyes) with opaque refracting media. Ultrasonic diagnostic equipment with a high level of computer support essentially improved the resolving capacity of echography and detected accessory acoustic signs of some congenital ocular diseases.

Ultrasound biomicroscopy in the screening of retinopathy of prematurity

PURPOSE

To report the use of ultrasound biomicroscopy in the screening of two premature infants with retinopathy of prematurity.

METHODS

Observational case reports. A premature infant born at 26 weeks' gestation had bilateral stage II, zone II retinopathy of prematurity at 36 weeks' gestation and was imaged with ultrasound biomicroscopy. A second premature infant born at 25 weeks' gestation developed subthreshold stage III, zone II retinopathy of prematurity in the right eye and was imaged with ultrasound biomicroscopy.

RESULTS

In case 1, ultrasound biomicroscopy imaged a ridge present nasally in zone II of the right eye, consistent with stage II retinopathy of prematurity. In case 2, ultrasound biomicroscopy imaged a neovascular frond present nasally in zone II of the right eye, consistent with stage III retinopathy of prematurity.

CONCLUSION

Ultrasound biomicroscopy may be useful for screening retinopathy of prematurity, when optical methods fail to visualize the peripheral retina.

[Use of ultrasonic method of examination in the diagnosis of retinopathy of prematurity]

A total of 164 children (328 eyes) aged 2 months to 3 years with stages L-V retinopathy neonatorum (RN) were examined. Ultrasonic examination of children with RN is an important accessory method in complex examination of the eyes in children with RN with exudative and fibrous changes of the vitreous and massive hemorrhages. Indications for the use of ultrasonic method of examination in children with RN are defined in order to evaluate the need in preventive laser or for kryocoagulation of the retina or diagnosis of retinal detachment in RN, particularly before surgery. This method helps predict the disease course and evaluate the time course of the process.

Efficacy of removal of buckle after scleral buckling surgery for retinopathy of prematurity

BACKGROUND OR PURPOSE: A series of encouraging reports over the past decade indicate that scleral buckling (SB) surgery may lessen or eliminate vitreoretinal traction in advanced retinopathy of prematurity (ROP). The effects of SB surgery on refraction and ocular growth, however, have not been demonstrated. We investigated the effects of postoperative removal of buckle in infants whose retinas were reattached in stage 4 ROP.

METHODS

Selected for study were 6 eyes of 3 patients whose retinas had been reattached by placing an encircling buckle, 2.5 mm in width, around the eye and whose buckles were subsequently removed. Axial lengths and refractive errors were compared before and after removal of the buckles. The patients were examined for at least 3 years after removal.

RESULTS

There was high myopia in all eyes treated for stage 4 ROP with SB. All retinas remained attached after removal of the buckle. Although there was a variable degree of increase in axial length, myopic refractive error tended to decrease after removal of the buckle.

CONCLUSIONS

There was some decrease in degree of myopia without resulting in retinal detachment or continued vitreous traction after buckle removal following SB surgery for ROP.

An ultrasonographic study of stage-5 retinopathy of prematurity

BACKGROUND

In preterm infants with severe retinopathy of prematurity, there is often a discrepancy between ophthalmic ultrasound findings and the ophthalmoscopic and/or intraoperative aspect of the eye.

METHODS

Six preterm infants (8 eyes) with stage-5 retinopathy of prematurity were examined with standardized ophthalmic echography (A and B scans) shortly before undergoing open-sky vitrectomies. Sonographic findings were evaluated according to four A-scan and four B-scan criteria used to diagnose retinal detachment in adults and compared to intraoperative findings.

RESULTS

Although the retinal detachments and vitreal proliferation found in all 8 eyes at surgery were almost identical, the sonographic aspects varied widely: 3/8 satisfied most of the criteria used in adults, 3/8 presented two criteria only and the remaining 2 were negative for all criteria used.

CONCLUSION

The variability in the ultrasonographic aspects of these preterm eyes may depend on the degree of maturity of the preterm retina at the time of examination, with more mature retinas presenting greater reflectivity and therefore greater visibility in the sonographic exam.

[Color Doppler imaging of central retinal artery in retinopathy of prematurity]

Color Doppler imaging (CDI) is a noninvasive technique, combining 2-dimensional brightness-modulated (B-mode) ultrasound evaluation of eye and orbital structures, with simultaneous color-coded Doppler imaging of orbital blood flow. It has been used to characterize various ophthalmic disorders in adults. Currently there is no data describing orbital blood flow parameters in either normal children or in those with ophthalmic disease, such as the retinopathy of prematurity (ROP). We evaluated blood flow in the central retinal artery of preterm infants undergoing examination for ROP. We also investigated whether useful readings could be obtained on a consistent basis, and the reproducibility of differences in central retinal artery blood flow between subjects with and without ROP (including the influence of "plus" disease). We obtained hemodynamic readings in 43 of 46 eyes of preterm infants. 13 eyes had no signs of ROP; 18 had ROP (at least stage 1) without "plus" disease, and 12 had ROP with "plus" disease. There were no statistically significant differences in systolic blood flow velocity within the 3 groups. However the average velocity was slower in the "plus" disease group, correlating with the clinical finding of dilated and tortuous blood vessels which characterize the posterior retina of ROP eyes with "plus" disease.

Color doppler imaging of the central retinal artery in premature infants undergoing examination for retinopathy of prematurity

PURPOSE

Recent attempts have been made to quantify blood flow velocity in the central retinal artery (CRA) of adults using color Doppler imaging (CDI). Although retinal vascular abnormalities are the hallmark of severe retinopathy of prematurity (ROP), normal values have not been established for CRA blood flow velocity in premature infants.

METHODS

CDI of the CRA was successfully performed on 43 eyes in 22 infants (postconceptional ages 32 to 39 weeks) before the infants underwent examination for ROP. Peak systolic velocity (PSV) and end diastolic velocity were recorded from at least 1 eye of each patient. Pourcelot's resistive index was then calculated for each eye studied.

RESULTS

Mean PSV for patients with no ROP (n = 6) was 7.2 +/- 1.5 cm/s, whereas those with any degree of ROP excluding plus disease (n = 9) had a mean PSV of 8.9 +/- 1.8 cm/s. Of the patients with ROP and plus disease (n = 7), the mean PSV was 7.0 +/- 1.6 cm/s. There were no statistically significant differences among these 3 groups (P= .08).

CONCLUSIONS

CDI can be successfully performed on preterm infants and yields values lower than those previously reported in healthy adult subjects. PSV in the CRA may be higher in subjects with ROP in the absence of plus disease; however, further study is needed to determine whether these differences are significant.

Differential diagnosis of leukokoria: radiologic-pathologic correlation

Leukokoria is an abnormal pupillary light reflection that usually results from an intraocular abnormality and is seen most often in children. One-half of the cases of childhood leukokoria are caused by retinoblastoma, a malignant tumor of immature retinoblasts that manifests in a normal-sized eye as a calcified mass, is often partially necrotic, and grows into the vitreous and through the choroid. Retinoblastoma enhances with contrast material and, unlike most tumors, may be darker than vitreous on T2-weighted images. When leukokoria is associated with microphthalmia, persistent hyperplastic primary vitreous (PHPV) (28% of cases) or retinopathy of prematurity (ROP) (5% of cases) should be considered. PHPV is a congenital, usually unilateral lesion that appears as a dense tubular mass extending from the lens to the retina along the course of the hyaloid canal. Hemorrhage from PHPV produces a subhyaloid (or subretinal) fluid collection, often with characteristic blood-fluid levels. ROP is bilateral and usually manifests in premature infants who received supplemental oxygen therapy. Coats disease (16% of leukokoria) is a sporadic unilateral idiopathic retinal telangiectasia that produces a lipoproteinaceous subretinal exudate leading to complete retinal detachment. The globe has normal size but increased attenuation and signal intensity from hemorrhage without calcification or enhancement. Toxocaral endophthalmitis (16% of leukokoria) is a granulomatous reaction to the parasite in the vitreous and uveoretinal coat. Retinal astrocytoma (3% of leukokoria), which manifests in a normal-sized globe, is an indolent benign neoplasm commonly associated with phakomatoses (usually tuberous sclerosis).

Axial length biometry in infants with retinopathy of prematurity

Ultrasound axial length measurements were obtained on infants under a birthweight of 1500 g or 32 weeks gestation undergoing screening for retinopathy of prematurity (ROP). A total of 496 readings were obtained on 171 infants between 32 and 41 weeks post-conceptual age. Other details recorded were maximum stage of acute ROP, birthweight, gestational age, sex, and biparietal and occipitofrontal head diameters. The relationship of these variables to axial growth of the eye was examined using analysis of covariance with a repeated measures approach. Mean axial length increased from 15.27 mm to 16.65 mm in the left eye during this period. Following adjustment for repeated readings a growth rate of 0.18 mm/week was obtained for both eyes. Male infants were found to have longer axial lengths despite correction for birthweight, gestation and head size (p < 0.0001 right and left). Higher stages of acute ROP were also associated with shorter axial length (p < 0.05 for all stages of both eyes) but the rate of growth during the study period did not demonstrate significant differences between stages. Stage 3 infants reaching the threshold for cryotherapy had shorter axial length than stage 3 infants not receiving treatment. The effect of prematurity on the growth of the eye and the significance of these findings with respect to the subsequent development of refractive errors in premature infants are discussed.

[Diagnostic value of continuous wave (cw) Doppler sonography in maternal diabetes mellitus]

Doppler studies of umbilical, uterine and arcuate artery velocity wave forms were performed in 40 insulin-dependent diabetic women in the first and second half of pregnancy. Using a continuous-wave Doppler device, the resistance index (RI) was calculated to determine the degree of vascular resistance in utero-placental and foeto-placental compartment. The 90th percentile was used to classify flow velocity profiles. In addition, diastolic notching and incomplete registration of uterine and arcuate arteries were considered as an abnormal result in utero-placental perfusion. The prevalence of abnormal velocity wave forms in this risk group was higher than in a non-diabetic population. No significant correlation was found between abnormal Doppler studies and White's classification. Patients with vasculopathy represent a high-risk group for foetal growth retardation, which may be detected early by umbilical and especially uterine artery Doppler studies. Abnormal uterine and arcuate artery wave forms allowed identification of patients who developed pregnancy-induced hypertension/preeclampsia.

Scleral buckling surgery for stage 4B retinopathy of prematurity

Results of scleral buckling in 15 consecutive eyes of 13 infants with stage 4B retinopathy of prematurity (ROP) were reviewed. Ten of 15 retinas achieved macular reattachment with a single scleral buckling procedure. Four of 15 retinas unable to be attached by scleral buckling were reattached after the addition of a single vitreous operation. One of 15 retinas was unable to be reattached despite both a scleral buckling and a single vitreous procedure. Despite macular attachment in all except one eye, visual results were disappointing. Fix and follow visual acuity was present in 3 eyes, light perception in 11 eyes, and no light perception in 1 eye. Average follow-up was 10 months. Possible causes for poor visual outcomes despite retinal reattachment include retinal abnormalities as a result of detachment and amblyopia.

Evaluation of eyes with advanced stages of retinopathy of prematurity using standardized echography

The authors evaluated 36 patients (72 eyes) who had either Stage 4 or Stage 5 retinopathy of prematurity (ROP) with standardized A-scan and B-scan echography. The eyes were evaluated for vitreous opacities, retrolental membranes, and retinal detachments. Stage 5 retinal detachments were present in 94% (68 of 72) of the eyes with 65% (47 of 72) having a wide anterior and narrow posterior configuration. Anterior retinal loops were noted in 36% of the eyes. Subretinal opacities were present in 47% of the eyes. Choroidal thickening and intraocular calcium were noted in 22% and 14% of eyes, respectively. The axial eye length was measured and adjusted for the differences in chronological and gestational age and compared with data from normal eyes. This showed that eyes with ROP were much smaller. The standardized A-scan was helpful in confirming the diagnosis of retinal detachment, evaluating the peripheral retina, and examining the subretinal space. The combination of A-scan and B-scan echography is helpful in predicting anatomic findings in patients with ROP undergoing surgery.

Calcification and ossification within the orbit

The radiological diagnosis of orbital lesions can be aided by an understanding of the significance of the various kinds of calcium deposits. Orbital calcification may be metastatic or dystrophic, with ossification occurring in degenerated eye tissue in the presence of an abundant blood supply. It is the dystrophic type which is usually visualized radiographically. Intraorbital calcification had been categorized according to its configuration and location (a) ocular; (b) extraocular; and (c) extraorbital extending into the orbit on frontal radiographs. Lesions discussed include cataract, phthisis bulbi, vascular abnormalities, infection, and tumor.