Causes of Childhood Blindness in the United States Using the IRIS® Registry (Intelligent Research in Sight)

[National protocol for diagnosis and care of retinopathy of prematurity: Summary for the attending physician]

Retinopathy of prematurity (ROP, ORPHA: 90050) is the main cause of visual impairment in preterm infants and the leading preventable cause of childhood blindness in high- and middle-income countries. However, severe stages of the disease remain rare. While screening recommendations for the disease are well-established in France, management of ROP requiring treatment is less standardized, especially since new therapeutic options have been approval on this indication. The management of preterm infants requiring treatment for ROP is complex and involves a multidisciplinary team, including pediatric ophthalmologists, vitreoretinal surgeons, neonatologists, pediatric anesthetists, nurses, and orthoptists, within an adapted structure for premature infants care. There is a genuine need to unify national practices, with a strong demand from physicians involved in ROP care along the country. The objective of this National Diagnostic and Care Protocol (PNDS) is to provide guidelines for diagnostic and management for ROP, and to optimize and harmonize the management of this disease across the country. The main treatment indications, the different treatment modalities including laser photocoagulation, anti-VEGF injections, and vitreoretinal surgery as well as follow-up calendar, are reviewed to establish the best practice recommendations on ROP.

Heme: A link between hemorrhage and retinopathy of prematurity progression

Neovascularization is implicated in the pathology of retinopathy of prematurity (ROP), diabetic retinopathy (DR), and age-related macular degeneration (AMD), which are the leading causes of blindness worldwide. In our work, we analyzed how heme released during hemorrhage affects hypoxic response and neovascularization. Our retrospective clinical analysis demonstrated, that hemorrhage was associated with more severe retinal neovascularization in ROP patients. Our heme-stimulated human retinal pigment epithelial (ARPE-19) cell studies demonstrated increased expression of positive regulators of angiogenesis, including vascular endothelial growth factor-A (VEGFA), a key player of ROP, DR and AMD, and highlighted the activation of the PI3K/AKT/mTOR/VEGFA pathway involved in angiogenesis in response to heme. Furthermore, heme decreased oxidative phosphorylation in the mitochondria, augmented glycolysis, facilitated HIF-1α nuclear translocation, and increased VEGFA/GLUT1/PDK1 expression suggesting HIF-1α-driven hypoxic response in ARPE-19 cells without effecting the metabolism of reactive oxygen species. Inhibitors of HIF-1α, PI3K and suppression of mTOR pathway by clinically promising drug, rapamycin, mitigated heme-provoked cellular response. Our data proved that oxidatively modified forms of hemoglobin can be sources of heme to induce VEGFA during retinal hemorrhage. We propose that hemorrhage is involved in the pathology of ROP, DR, and AMD.

Update on Epidemiologic Trends in Causes of Childhood Blindness and Severe Visual Impairment in East Africa

OBJECTIVE

The initiative 2030 In Sight and the International Agency for the Prevention of Blindness have developed a plan to mitigate the global burden of preventable sight loss. One priority of this initiative is obtaining population eye health data. East Africa is a region that has historically been plagued by high rates of vision loss, and it is imperative to understand what causes are at play. Two large cross-sectional studies were previously published in 1995 and 2009, reporting the causes of childhood blindness (BL) and severe visual impairment (SVI) in East Africa. An update regarding more recent causes is warranted to better understand the trends of childhood BL/SVI in this region.

METHODS

A search strategy was developed a priori to identify relevant terms and align them with a standardized definition of East Africa. This strategy was then employed across PubMed, Google Scholar, and Scopus, with the yield of the overall search depicted in a Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 flow diagram. In the articles gathered by the search, causes of BL/SVI were typically categorized by anatomy and etiology.

RESULTS

Eight articles met the criteria, with data from 6 countries, consisting of 534 cases of childhood BL/SVI. Common anatomic locations identified included the cornea, lens, and whole globe. Among the most common etiologies were corneal scarring/opacity and cataract. Systemic etiologies and disease associations included measles, toxoplasmosis, and prematurity. Presumptive infectious disease and hereditary conditions were also identified as a category, but specific identification of etiologies and genetic diagnosis was largely unavailable.

CONCLUSIONS

BL/SVI due to the cornea was among the common anatomic sites of disease in our study. The identification of measles as an associated systemic etiology requires further understanding in the context of increased vaccination programs. Multiple articles acknowledged that cataract has become the predominant cause of BL/SVI owing to increased measles vaccination and vitamin A supplementation. Additional research should be conducted to gain a complete understanding of childhood BL/SVI in East Africa, and responses at regional and national levels are likely necessary to address treatable causes of vision impairment.

Excellent accuracy of trained neonatal nurses in the detection of referral-warranted retinopathy of prematurity within an established telemedicine screening programme

AIM

To evaluate level of agreement of specialist trained retinopathy of prematurity (ROP) nurses compared with an experienced paediatric ophthalmologist in detection of referral-warranted ROP (RWROP) using wide-field digital retinal imaging.

METHODS

This is a prospective, observational, blinded study of neonates in a level III neonatal intensive care unit, from July 2020 to November 2022. Image capture using wide-field digital retinal imaging followed by ROP grading and staging was completed by trained ROP nurses. This was then compared with findings by an experienced paediatric ophthalmologist. The primary outcome was presence of RWROP in either eye.

RESULTS

One hundred and ninety-five neonates (55% male) with a total of 768 screening visits were included. At the initial screen, nurse and ophthalmologist agreed about presence of RWROP for 191 of 195 neonates (98%, kappa = 0.79, P < 0.0001), with 100% sensitivity for RWROP detection. Including all 768 screening episodes, agreement was 98% for RWROP. There was disagreement in 16 screenings (2%) for 11 (6%) neonates. Of the five screenings (0.7%) that the ophthalmologist thought were RWROP and the nurse did not, three were disagreements about whether the zone was posterior zone 2 or zone 1.

CONCLUSIONS

We found excellent levels of agreement and add evidence that interpretations by specialist trained nurses could be safely integrated into a 'hybrid ROP screening system'.

Single-line macular optic coherence tomography to confirm optic neuropathies in awake infants and young children

BACKGROUND

Handheld optical coherence tomography (HH-OCT) can image awake, young children but lacks integrated segmentation/analysis software. OCT imaging of eyes with optic neuropathies demonstrates ganglion cell layer (GCL) and ganglion cell complex (GCC) thinning, with a normal or thickened inner nuclear layer (INL). We compared pediatric normative data with GCL/INL and GCC/INL ratios from HH-OCT macular scans of awake young children with clinically diagnosed optic neuropathies.

METHODS

Macular HH-OCT from awake children with optic neuropathies was prospectively obtained using Bioptigen (Leica Microsystems, Wetzlar, Germany). The GCL, GCC, and INL were manually measured by two readers using ImageJ from single-line macular scans at the thickest points nasal and temporal to the fovea, respectively, and the GCL/INL and GCC/INL ratios were calculated and compared with normative data.

RESULTS

HH-OCT images from 17 right eyes of 17 children (mean age, 4.3 ± 2.9 years) with optic neuropathies were analyzed. Mean nasal (17 eyes) and temporal (16 eyes) GCL/INL ratios with optic neuropathies were 0.44 ± 0.38 (95% CI, 0.26-0.62) and 0.26 ± 0.22 (95% CI, 0.15-0.36), respectively. Corresponding normative GCL/INL ratios are 1.26 ± 0.20 (95% CI, 1.19-1.34) and 1.23 ± 0.27 (95% CI, 1.13-1.33), respectively (P < 0.0001). Severe thinning precluded GCL measurements in 2 eyes nasally and 5 eyes temporally, resulting in GCL measurements of zero. Mean nasal (17 eyes) and temporal (16 eyes) GCC/INL ratios were 1.93 ± 0.70 (95% CI,1.60-2.27) and 1.67 ± 0.44 (95% CI,1.46-1.87). Corresponding normative ratios are 2.85 ± 0.38 (95% CI, 2.71-2.99) and 2.87 ± 0.42 (95% CI, 2.70-3.03), respectively (P < 0.0001).

CONCLUSIONS

GCL/INL and GCC/INL ratios calculated from single-line macular HH-OCT scans in awake young children with optic neuropathies differ significantly from normative values and may thus have utility in helping to establish a diagnosis of optic neuropathy.

Validation of the "TWO-ROP" Algorithm at a Multi-Neonatal Intensive Care Unit Tertiary Referral Center

PURPOSE

We aim to validate the previously published TWO-ROP algorithm on an external data set.

DESIGN

Retrospective consecutive study.

SUBJECTS

Infants screened for retinopathy of prematurity (ROP) between January 2013 and August 2023 at a tertiary referral multi-site.

METHODS

Infants with higher birth weight (BW) and greater gestational age (GA) were included and stratified into 3 groups as follows: group 1 (BW <1500 g, GA ≥30 weeks), group 2 (BW ≥1500 g, GA <30 weeks), and group 3 (BW ≥1500 g, GA ≥30 weeks).

MAIN OUTCOME MEASURES

The rate of ROP, treatment-warranted ROP (TW-ROP), and number of inpatient examinations were evaluated in the 3 groups.

RESULTS

In total, 1095 (33.8%) patients met the inclusion criteria. The number of patients in groups 1, 2, and 3 was 837 (76.4%), 72 (6.6%), and 186 (17.0%), respectively. Retinopathy of prematurity was detected in 120 (11.0%) patients; the rate was 9.8% in group 1, 20.8% in group 2, and 12.4% in group 3 (P = 0.013). The overall mean number of inpatient examinations for patients undergoing traditional, TWO-ROP 36-week, and TWO-ROP 40-week screening systems was 1.95, 1.43, and 0.99, respectively (P < 0.001). Stage 3 was found in 9 eyes of 5 patients (0.5%, all zone II). Three eyes of 2 patients (0.2%) had plus disease. Two patients had bilateral laser treatment at 44 and 39.4 weeks postconceptional age (PCA); 3 out of 4 of these eyes met type 1 treatment criteria. Overall, the ROP screening burden saved was 9.0% and 16.7% for the TWO-ROP 36-week and 40-week systems, respectively. The sensitivity for TW-ROP was 100% for TWO-ROP 36-week system and 99.4% for TWO-ROP 40-week system.

CONCLUSION

The TWO-ROP algorithm can reduce the number of inpatient examinations while maintaining safety. To ensure timely management, we recommend that the single first ROP examination occur at 38 to 39 weeks PCA.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Association of Speckle-Based Blood Flow Measurements and Fluorescein Angiography in Infants with Retinopathy of Prematurity

Purpose

To determine the correlation between blood flow metrics measured by intravenous fluorescein angiography (IVFA) and the blood flow velocity index (BFVi) obtained by laser speckle contrast imaging (LSCI) in infants with retinopathy of prematurity (ROP).

Design

Prospective comparative pilot study.

Subjects

Seven eyes from 7 subjects with ROP.

Methods

Unilateral LSCI and IVFA data were obtained from each subject in the neonatal intensive care unit. Five LSCI-based metrics and 5 IVFA-based metrics were extracted from images to quantify blood flow patterns in the same region of interest. Correlation between LSCI-based and IVFA-based blood flow metrics was compared between 2 subgroups of ROP severity: moderate ROP (defined as stage ≤ 2 without Plus disease) and severe ROP (defined as stage ≥3 or Plus disease).

Main Outcome Measures

Pearson and Kendall rank correlation coefficients between IVFA and LSCI metrics; Student t test P values comparing LSCI metrics between "severe" and "moderate" ROP groups.

Results

Pearson correlations between IVFA and LSCI included arterial-venous transit time (AVTT) and peak BFVi (pBFVi; r = -0.917; P = 0.004), AVTT and dip BFVi (dBFVi; r = -0.920; P = 0.003), AVTT and mean BFVi (r = -0.927- P = 0.003), and AVTT and volumetric rise index (r = -0.779; P = 0.039). Kendall rank correlation between AVTT and dBFVi was r = -0.619 (P = 0.051). pBFVi was higher in severe ROP than in moderate ROP (8.4 ± 0.6 and 4.4 ± 1.8, respectively; P = 0.0045 using the 2-sample t test with pooled variance and P = 0.0952 using the Wilcoxon rank-sum test).

Conclusions

Correlation was found between blood flow metrics obtained by IVFA and noninvasive LSCI techniques. We demonstrate the feasibility of obtaining quantitative metrics using LSCI in infants with ROP in this pilot study; however, further investigation is needed to evaluate its potential use in clinical assessment of ROP severity.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Retinal blood flow association with age and weight in infants at risk for retinopathy of prematurity

This prospective study evaluated the relationship between laser speckle contrast imaging (LSCI) ocular blood flow velocity (BFV) and five birth parameters: gestational age (GA), postmenstrual age (PMA) and chronological age (CA) at the time of measurement, birth weight (BW), and current weight (CW) in preterm neonates at risk for retinopathy of prematurity (ROP). 38 Neonates with BW < 2 kg, GA < 32 weeks, and PMA between 27 and 47 weeks underwent 91 LSCI sessions. Correlation tests and regression analysis were performed to quantify relationships between birth parameters and ocular BFV. Mean ocular BFV index in this cohort was 8.8 +/- 4.0 IU. BFV positively correlated with PMA (r = 0.3, p = 0.01), CA (r = 0.3, p = 0.005), and CW (r = 0.3, p = 0.02). BFV did not correlate with GA nor BW (r = - 0.2 and r = - 0.05, p > 0.05). Regression analysis with mixed models demonstrated that BFV increased by 1.2 for every kilogram of CW, by 0.34 for every week of CA, and by 0.36 for every week of PMA (p = 0.03, 0.004, 0.007, respectively). Our findings indicate that increased age and weight are associated with increased ocular BFV measured using LSCI in premature infants. Future studies investigating the associations between ocular BFV and ROP clinical severity must control for age and/or weight of the infant.

Using Natural Language Processing to Identify Different Lens Pathology in Electronic Health Records

PURPOSE

Nearly all published ophthalmology-related Big Data studies rely exclusively on International Classification of Diseases (ICD) billing codes to identify patients with particular ocular conditions. However, inaccurate or nonspecific codes may be used. We assessed whether natural language processing (NLP), as an alternative approach, could more accurately identify lens pathology.

DESIGN

Database study comparing the accuracy of NLP versus ICD billing codes to properly identify lens pathology.

METHODS

We developed an NLP algorithm capable of searching free-text lens exam data in the electronic health record (EHR) to identify the type(s) of cataract present, cataract density, presence of intraocular lenses, and other lens pathology. We applied our algorithm to 17.5 million lens exam records in the Sight Outcomes Research Collaborative (SOURCE) repository. We selected 4314 unique lens-exam entries and asked 11 clinicians to assess whether all pathology present in the entries had been correctly identified in the NLP algorithm output. The algorithm's sensitivity at accurately identifying lens pathology was compared with that of the ICD codes.

RESULTS

The NLP algorithm correctly identified all lens pathology present in 4104 of the 4314 lens-exam entries (95.1%). For less common lens pathology, algorithm findings were corroborated by reviewing clinicians for 100% of mentions of pseudoexfoliation material and 99.7% for phimosis, subluxation, and synechia. Sensitivity at identifying lens pathology was better for NLP (0.98 [0.96-0.99] than for billing codes (0.49 [0.46-0.53]).

CONCLUSIONS

Our NLP algorithm identifies and classifies lens abnormalities routinely documented by eye-care professionals with high accuracy. Such algorithms will help researchers to properly identify and classify ocular pathology, broadening the scope of feasible research using real-world data.

Efficacy of supplemental oxygen in reducing the need for laser or intravitreal bevacizumab in preterm infants with stage 2 retinopathy of prematurity

BACKGROUND

Retinopathy of prematurity (ROP) is a disease that affects preterm infants born younger than 30 weeks of gestation. The pathophysiology of ROP involves an initial vaso-obliterative phase followed by vaso-proliferative phase that leads to disease progression. The use of supplemental oxygen during the vaso-proliferative phase of ROP has been associated with reduced disease progression, but how this impacts the need for ROP treatment is unclear. The goal of this study was to compare the rate of laser or intravitreal bevacizumab after implementation of a new supplemental oxygen therapy protocol in preterm infants with stage 2 ROP.

METHODS

This is a retrospective chart review of preterm infants diagnosed with stage 2 ROP at Riley Hospital for Children between 1/2017 and 12/2022. Patients diagnosed between 1/2017 and 6/2020 were classified as Cohort A, preprotocol implementation. Patients diagnosed from 8/2020 to 12/2022 were classified as Cohort B, postprotocol implementation. In Cohort A, oxygen saturation was kept at 91-95% through the entire hospitalization. In Cohort B, oxygen saturation was increased to 97-99% as soon as Stage 2 ROP was diagnosed. Statistical analyses were performed using chi-square and Student's T test, followed by multivariate analyses to determine the impact of the oxygen protocol on the need for ROP treatment.

RESULTS

A total of 211 patients were diagnosed with stage 2 ROP between 1/2017 and 12/2022. Of those patients, 122 were before protocol implementation therapy (Cohort A), and 89 were after implementation of supplemental oxygen protocol (Cohort B). Gestational age was slightly higher in Cohort B (Cohort A 25.3 ± 1.9, Cohort B 25.8 ± 1.84, p = 0.04). There was no difference in birth weight, NEC, BPD, or survival. Cohort B had lesser need for invasive mechanical ventilation and higher days on CPAP during hospitalization. Notably, Cohort A had 67 (55%) patients treated with laser photocoagulation or intravitreal bevacizumab versus 20 (22%) patients in Cohort B (OR 0.19, 0.08-0.40).

CONCLUSION

The need for laser photocoagulation or intravitreal bevacizumab was significantly decreased in high-risk patients treated with the supplemental oxygen protocol. This result supports the idea that targeted supplemental oxygen therapy to keep saturations between 97 and 99% can reduce disease progression in infants with stage 2 ROP and potentially decrease the burden of additional procedures.

Multi-registry analysis of patients with multiple sclerosis and neuromyelitis optica to improve capture of demographic data and compare visual outcomes

IMPORTANCE

The American Academy of Neurology Axon Registry® provides real-world data for patients with multiple sclerosis and neuro-myelitis optica. However, some data are incomplete (e.g. demographics) and some relevant outcomes are not systematically captured in neurology documentation (e.g. visual acuity). The American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight) contains demographic and visual function data that may complement Axon Registry-derived data to enhance understanding of real-world visual outcomes in neurological disease.

OBJECTIVE

To combine Axon Registry and IRIS Registry data to reduce missingness of demographic information and characterize visual outcomes in patients with multiple sclerosis and neuro-myelitis optica.

DESIGN

Cross-sectional study.

SETTING

Outpatient neurology and ophthalmology clinical practices.

PARTICIPANTS

Patients participating in both registries between January 1, 2014 through December 10, 2021 were included if they had repeat ICD-9/10 codes for with multiple sclerosis or neuro-myelitis optica in the Axon registry.

EXPOSURE

Diagnosis (multiple sclerosis or neuro-myelitis optica).

MAIN OUTCOME AND MEASURE

Age, sex, race and ethnicity were assessed in the individual registries and classified as conflicting, missing, or not missing in the combined data set. The IRIS Registry contributed visual acuity data.

RESULTS

Among 60,316 patients with multiple sclerosis and 1,068 patients with neuro-myelitis optica in the Axon Registry, 14,085 and 252 had temporal overlap in the IRIS Registry. Combining data reduced missing or conflicting data for race and ethnicity by 15-19 % (absolute reduction, all p ≤ 0.0005), but not age (p = 1.0) or gender (p = 0.08). 10,907 patients with MS and 142 with NMO had visual acuity data in the IRIS Registry. Visual acuity averaged between eyes was worse in patients with NMO after adjusting for age and gender (0.17 logMAR, 95 %CI 0.12,0.21, p < 0.0005).

CONCLUSION AND RELEVANCE

Using data from two registries reduced missing data for race and ethnicity and enabled examination of outcomes captured in the IRIS Registry for conditions that are diagnosed more frequently in the Axon Registry, demonstrating the utility of a multi-registry analysis.

Management of Icteric Vitreous, Retinal Opacification, and Atypical Retinopathy of Prematurity

A dichorionic, diamniotic twin born at 24-0/7 weeks and 740 g developed hyperbilirubinemia, necrotizing enterocolitis, and sepsis. Photographic imaging documented vitreous opacification, which was absent in the fellow twin. Retinal opacification was presumed secondary to embolic sepsis and responded to systemic antibiotics. Subsequent dropout of vascularized retina corresponded to areas of retinal opacification. Type 1 retinopathy of prematurity (ROP)-Zone I, Stage 3 ROP bilateral-demonstrated a rapid and durable response to off-label intravitreal bevacizumab 0.625 mg. Retinal opacification resolved between 39 and 40 weeks postmenstrual age. Systemic comorbidities may alter the appearance, course, and management of ROP. [Ophthalmic Surg Lasers Imaging Retina 2024;55:164-167.].

Retinal blood flow association with age and weight in infants at risk for retinopathy of prematurity

This prospective study evaluated the relationship between laser speckle contrast imaging (LSCI) ocular blood flow velocity (BFV) and five birth parameters: gestational age (GA), postmenstrual age (PMA), and chronological age (CA) at the time of measurement, birth weight (BW), and current weight (CW) in preterm neonates at risk for retinopathy of prematurity (ROP).38 Neonates with BW < 2 kg, GA < 32 weeks, and PMA between 27-47 weeks underwent 91 LSCI sessions. Correlation tests and regression analysis were performed to quantify relationships between birth parameters and ocular BFV. Mean ocular BFV index in this cohort was 8.8 +/- 4.0 IU. BFV positively correlated with PMA (r = 0.3, p = 0.01), CA (r = 0.3, p = 0.005), and CW (r = 0.3, p = 0.02). BFV did not correlate with GA nor BW (r=-0.2 and r=-0.05, p > 0.05). Regression analysis with mixed models demonstrated that BFV increased by 1.2 for every kilogram of CW, by 0.34 for every week of CA, and by 0.36 for every week of PMA (p = 0.03, 0.004, 0.007, respectively). Our findings indicate that increased age and weight are associated with increased ocular BFV measured using LSCI in premature infants. Future studies investigating the associations between ocular BFV and ROP clinical severity must control for age and/or weight of the infant.

Identifying novel candidate compounds for therapeutic strategies in retinopathy of prematurity via computational drug-gene association analysis

Purpose

Retinopathy of prematurity (ROP) is the leading cause of preventable childhood blindness worldwide. Although interventions such as anti-VEGF and laser have high success rates in treating severe ROP, current treatment and preventative strategies still have their limitations. Thus, we aim to identify drugs and chemicals for ROP with comprehensive safety profiles and tolerability using a computational bioinformatics approach.

Methods

We generated a list of genes associated with ROP to date by querying PubMed Gene which draws from animal models, human studies, and genomic studies in the NCBI database. Gene enrichment analysis was performed on the ROP gene list with the ToppGene program which draws from multiple drug-gene interaction databases to predict compounds with significant associations to the ROP gene list. Compounds with significant toxicities or without known clinical indications were filtered out from the final drug list.

Results

The NCBI query identified 47 ROP genes with pharmacologic annotations present in ToppGene. Enrichment analysis revealed multiple drugs and chemical compounds related to the ROP gene list. The top ten most significant compounds associated with ROP include ascorbic acid, simvastatin, acetylcysteine, niacin, castor oil, penicillamine, curcumin, losartan, capsaicin, and metformin. Antioxidants, NSAIDs, antihypertensives, and anti-diabetics are the most common top drug classes derived from this analysis, and many of these compounds have potential to be readily repurposed for ROP as new prevention and treatment strategies.

Conclusion

This bioinformatics analysis creates an unbiased approach for drug discovery by identifying compounds associated to the known genes and pathways of ROP. While predictions from bioinformatic studies require preclinical/clinical studies to validate their results, this technique could certainly guide future investigations for pathologies like ROP.