Implementation of optical coherence tomography in retinopathy of prematurity screening

PURPOSE OF REVIEW

In this review, we explore the investigational applications of optical coherence tomography (OCT) in retinopathy of prematurity (ROP), the insights they have delivered thus far, and key milestones for its integration into the standard of care.

RECENT FINDINGS

While OCT has been widely integrated into clinical management of common retinal diseases, its use in pediatric contexts has been undermined by limitations in ergonomics, image acquisition time, and field of view. Recently, investigational handheld OCT devices have been reported with advancements including ultra-widefield view, noncontact use, and high-speed image capture permitting real-time en face visualization. These developments are compelling for OCT as a more objective alternative with reduced neonatal stress compared to indirect ophthalmoscopy and/or fundus photography as a means of classifying and monitoring ROP.

SUMMARY

OCT may become a viable modality in management of ROP. Ongoing innovation surrounding handheld devices should aim to optimize patient comfort and image resolution in the retinal periphery. Future clinical investigations may seek to objectively characterize features of peripheral stage and explore novel biomarkers of disease activity.

PROLIFERATIVE RETINOPATHY IN A 13-YEAR-OLD WITH ADAMS-OLIVER SYNDROME

PURPOSE

Adams-Oliver syndrome is a rare, inherited disorder of embryologic development that affects multiple systems. Ocular manifestations have been poorly characterized because of the low prevalence and high mortality of the disease when it is associated with internal organ and/or ophthalmic manifestations. We present a case of Adams-Oliver syndrome in a 13-year-old patient whose multimodal retinal imaging findings helped direct management.

METHODS

Single patient case report reviewing medical records and imaging.

RESULTS

Visual acuity upon presentation was 20/40 in each eye. Ultra-widefield fluorescein angiography revealed peripheral nonperfusion with terminal vascular bulbs, and leakage from a temporal fibrovascular complex in the left eye. Fundus autofluorescence imaging showed hyperautofluorescence associated with optic disc drusen and the fibrovascular complex. Treatment with targeted laser photocoagulation was associated with regression of the neovascularization.

CONCLUSION

Retinal manifestations of Adams-Oliver syndrome as observed with ultra-widefield fundus imaging may resemble those of familial exudative vitreoretinopathy and retinopathy of prematurity. Treatment of avascular retina with panretinal photocoagulation can be considered.

Prevalence of persistent avascular retina in untreated children with a history of retinopathy of prematurity screening

Persistent avascular retina (PAR) in prematurely born individuals may be a risk factor for late sequelae of retinopathy of prematurity (ROP), including retinal detachment in older childhood and adulthood. Although PAR has been associated with use of vascular endothelial growth factor antagonist therapy for treatment-requiring ROP, the prevalence of this finding in patients without prior ROP treatment is unknown. We performed a cross-sectional study to determine the prevalence of PAR in a cohort of patients 4-8 years of age who were screened for ROP in the neonatal intensive care unit and did not receive treatment. Patients were recruited from an existing population-based cohort and underwent ultra-widefield fluorescein angiography (UWFFA). UWFFA images of 43 eyes of 23 patients were evaluated. Average age at time of evaluation was 6.2 years. PAR was observed in 21 patients (91%). Thirteen eyes (30%) had PAR in zone II; 23 (53%), in zone III. Six eyes (14%) had abnormal vessels without clear PAR. These findings indicate a high prevalence of PAR in patients with a history of ROP screening without treatment.

Applications of interpretability in deep learning models for ophthalmology

PURPOSE OF REVIEW

In this article, we introduce the concept of model interpretability, review its applications in deep learning models for clinical ophthalmology, and discuss its role in the integration of artificial intelligence in healthcare.

RECENT FINDINGS

The advent of deep learning in medicine has introduced models with remarkable accuracy. However, the inherent complexity of these models undermines its users' ability to understand, debug and ultimately trust them in clinical practice. Novel methods are being increasingly explored to improve models' 'interpretability' and draw clearer associations between their outputs and features in the input dataset. In the field of ophthalmology, interpretability methods have enabled users to make informed adjustments, identify clinically relevant imaging patterns, and predict outcomes in deep learning models.

SUMMARY

Interpretability methods support the transparency necessary to implement, operate and modify complex deep learning models. These benefits are becoming increasingly demonstrated in models for clinical ophthalmology. As quality standards for deep learning models used in healthcare continue to evolve, interpretability methods may prove influential in their path to regulatory approval and acceptance in clinical practice.

Tauroursodeoxycholic Acid Protects Retinal and Visual Function in a Mouse Model of Type 1 Diabetes

PURPOSE

Previous studies demonstrated that systemic treatment with tauroursodeoxycholic acid (TUDCA) is protective in in vivo mouse models of retinal degeneration and in culture models of hyperglycemia. This study tested the hypothesis that TUDCA will preserve visual and retinal function in a mouse model of early diabetic retinopathy (DR).

METHODS

Adult C57BL/6J mice were treated with streptozotocin (STZ) and made diabetic at 8-10 weeks of age. Control and diabetic mice were treated with vehicle or TUDCA starting 1 or 3 weeks after induction of diabetes, and were assessed bimonthly for visual function via an optomotor response and monthly for retinal function via scotopic electroretinograms.

RESULTS

Diabetic mice showed significantly reduced spatial frequency and contrast sensitivity thresholds compared to control mice, while diabetic mice treated early with TUDCA showed preservation at all timepoints. A-wave, b-wave, and oscillatory potential 2 (OP2) amplitudes decreased in diabetic mice. Diabetic mice also exhibited delays in a-wave and OP2-implicit times. Early TUDCA treatment ameliorated a-wave, b-wave, and OP2 deficits. Late TUDCA treatment showed reduced preservation effects compared to early treatment.

CONCLUSIONS

Early TUDCA treatment preserved visual function in an STZ-mouse model of Type I diabetes. These data add to a growing body of preclinical research that may support testing whether TUDCA may be an effective early clinical intervention against declining visual function caused by diabetic retinopathy.

Phenotypic Spectrum of Pentosan Polysulfate Sodium-Associated Maculopathy: A Multicenter Study

Importance

A unique pigmentary maculopathy was recently described in 6 patients with long-term exposure to pentosan polysulfate sodium (PPS), a long-standing oral therapy for interstitial cystitis.

Objective

To characterize the exposure characteristics and clinical manifestations of PPS-associated maculopathy.

Design, Setting, and Participants

In this multi-institutional case series, medical records of patients who exhibited the characteristic maculopathy in the setting of prior PPS exposure were retrospectively reviewed. Data were collected from August 1, 2012, to October 1, 2018, and data were analyzed from October 2018 to January 2019.

Main Outcomes and Measures

Drug exposure, visual acuity, and retinal imaging characteristics.

Results

Of the 35 included patients (70 eyes), 34 (97%) were female, and the median (range) age was 60 (37-79) years. The median (range) duration of PPS intake was 15 (3-22) years, and the median (range) cumulative exposure was 1.61 (0.44-4.31) kg. The leading visual symptoms were metamorphopsia, blurred vision, and prolonged dark adaptation. Median (range) logMAR visual acuity of all eyes was 0.10 (-0.12 to 1.18). Fundus examination often revealed hyperpigmented macular spots (34 of 64 eyes [53%]) with interspersed pale-yellow deposits, although less commonly in eyes that exhibited retinal pigment epithelial atrophy (6 of 26 eyes [23%]; P < .001). Optical coherence tomography showed foci of retinal pigment epithelium elevation or thickening associated with hyperreflectance on near-infrared reflectance imaging. Fundus autofluorescence imaging typically revealed a symmetric, confluent pattern of hyperautofluorescent and hypoautofluorescent spots that involved the fovea in all eyes and extended to the retinal periphery in 24 eyes (36%). Longitudinal evaluation demonstrated dynamic changes in pigmentary abnormalities.

Conclusions and Relevance

These findings suggest that PPS-associated maculopathy is a vision-threatening condition that can manifest in the setting of long-term exposure to the drug. Multimodal imaging posits a distinctive clinical phenotype, characterized in this cohort by dynamic alterations within the retinal pigment epithelium and at the retinal pigment epithelium-photoreceptor interface. Ongoing work might explore causality and direct screening guidelines.

Late-Stage Sorsby Fundus Dystrophy Manifesting Severe Vision Loss in the Absence of Choroidal Neovascularization

A patient with a family history of molecularly confirmed Sorsby fundus dystrophy (SFD) presented with 9 years of progressive, bilateral central vision loss. Specific mutation analysis of the TIMP3 gene confirmed SFD, identifying a pathogenic mutation of p.Ser204Cys:c.610A>T. Optical coherence tomography imaging revealed diffuse retinal, retinal pigment epithelium, and choroidal atrophy without evidence for choroidal neovascularization (CNV). Although SFD is classically associated with CNV and subretinal fibrosis, some cases follow an atrophic course in the absence of CNV formation. This case highlights the extent to which extensive atrophic degeneration can lead to visual disability without choroidal neovascularization in late-stage SFD. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e215-e217.].

COMPLETE ATRIOVENTRICULAR SEPTAL DEFECTS DENGAN POLISITEMIA SEKUNDER

Atrioventricular septal defect (AVSD) adalah kelainan berupa defek pada septum atrioventrikular (AV) di atas atau bawah katup AV, disertai kelainan katup AV; terjadi akibat pertumbuhan yang abnormal dari endokardial cushion pada masa janin. AVSD mewakili 4% sampai 5% bawaan cacat jantung. Dilaporkan seorang pasien laki–laki 20 tahun dengan keluhan sesak nafas saat beraktivitas dan berkurang dengan istirahat, disertai bibir dan kuku jari yang membiru, sakit kepala hilang timbul, muka kemerahan, demam, lemah letih lesu dan dada rasa berdebar-debar. Adanya sianosis, kulit kemerahan, Konjungtiva hiperemis, peningkatan JVP, hepatojugular refluks, bentuk dada abnormal. Bunyi jantung reguler, terdengar bising sistolik di RIC VI, blowing, grade 4/6, punctum maximum di apeks, penjalaran ke Axilla. Bising sistolik di RIC V linea strenalis dektra, grade 4/6, blowing punctum maksimun di RIC V linea sternalis dektra. Pada pemeriksaan laboratorium didapatkan polisitemia. Pada rontgent dada terdapat kardiomegali, dari ekokardiografi adanya CAVSD, hipertensi pulmonal Moderate-severe, Left arch, fungsi RV yang menurun. Pada pasien dilakukan prosedur flebotomi untuk mengurangi kepekatan darah. Pengobatan hipertensi pulmonal pada pasien ini adalah dengan pemberian diuretik dan dorner.

COMPLETE ATRIOVENTRICULAR SEPTAL DEFECTS DENGAN POLISITEMIA SEKUNDER

Atrioventricular septal defect (AVSD) adalah kelainan berupa defek pada septum atrioventrikular (AV) di atas atau bawah katup AV, disertai kelainan katup AV; terjadi akibat pertumbuhan yang abnormal dari endokardial cushion pada masa janin. AVSD mewakili 4% sampai 5% bawaan cacat jantung. Dilaporkan seorang pasien laki–laki 20 tahun dengan keluhan sesak nafas saat beraktivitas dan berkurang dengan istirahat, disertai bibir dan kuku jari yang membiru, sakit kepala hilang timbul, muka kemerahan, demam, lemah letih lesu dan dada rasa berdebar-debar. Adanya sianosis, kulit kemerahan, Konjungtiva hiperemis, peningkatan JVP, hepatojugular refluks, bentuk dada abnormal. Bunyi jantung reguler, terdengar bising sistolik di RIC VI, blowing, grade 4/6, punctum maximum di apeks, penjalaran ke Axilla. Bising sistolik di RIC V linea strenalis dektra, grade 4/6, blowing punctum maksimun di RIC V linea sternalis dektra. Pada pemeriksaan laboratorium didapatkan polisitemia. Pada rontgent dada terdapat kardiomegali, dari ekokardiografi adanya CAVSD, hipertensi pulmonal Moderate-severe, Left arch, fungsi RV yang menurun. Pada pasien dilakukan prosedur flebotomi untuk mengurangi kepekatan darah. Pengobatan hipertensi pulmonal pada pasien ini adalah dengan pemberian diuretik dan dorner.

Early Onset Neovascular Inflammatory Vitreoretinopathy Due to a De Novo CAPN5 Mutation: Report of a Case

Autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is a rare autoimmune condition that typically presents as progressive uveitis and vitreoretinal degeneration between the second and third decades of life. Though traditionally attributed to inherited mutations of the CAPN5 gene, few reports of de novo variants exist. This report of vision and hearing loss in a 3 year-old girl describes the youngest documented case of ADNIV due to a de novo pathogenic c.865C>T (p.Arg289Trp) CAPN5 variant, illustrating the early stages of this enigmatic disease process.

Use of percutaneous bleomycin sclerotherapy for orbital lymphatic malformations

PURPOSE

Bleomycin sclerotherapy has been shown to be a viable treatment for lymphatic malformations. However, its use for these lesions confined to the orbit is becoming increasingly documented in the literature. In this study, we summarize the clinical manifestations and outcomes observed following percutaneous bleomycin sclerotherapy for orbital lymphatic malformation.

METHODS

A 5-year retrospective chart review of patients with clinical, radiographic, and/or biopsy-confirmed diagnoses of orbital lymphatic malformation that received bleomycin sclerotherapy was conducted at the Emory Hospital and Clinics. Data examined included patient demographics, patient history and symptoms, clinical findings, radiographic findings, route of bleomycin delivery, and outcome.

RESULTS

Of the 10 patients who met inclusion criteria, the median age of treatment was 7 years. The most common presenting symptoms included vision change and proptosis. Nine of 10 patients demonstrated macrocysts (>1 cm) on imaging. Seven of 10 patients had histories of prior interventions including resections, cyst drainage, and debulking. Because 2 of these 10 patients were lost to follow-up, 8 patients remained for post-procedural evaluation. Four of these eight showed improvement of visual acuity after post-bleomycin sclerotherapy. In seven of eight patients, extraocular motility either improved or remained stable. Pretreatment and posttreatment exophthalmometer measurements obtained in four patients revealed an average improvement in proptosis of 65% from their average pretreatment measurements.

CONCLUSIONS

Our findings suggest that percutaneous bleomycin sclerotherapy is a viable option for treatment of orbital lymphatic malformations, with potentially greater benefit to those with macrocystic features.

TrkB signalling pathway mediates the protective effects of exercise in the diabetic rat retina

Diabetic retinopathy is a leading cause of vision loss. Treatment options for early retinopathy are sparse. Exercise protects dying photoreceptors in models of retinal degeneration, thereby preserving vision. We tested the protective effects of exercise on retinal and cognitive deficits in a type 1 diabetes model and determined whether the TrkB pathway mediates this effect. Hyperglycaemia was induced in Long Evans rats via streptozotocin injection (STZ; 100 mg/kg). Following confirmed hyperglycaemia, both control and diabetic rats underwent treadmill exercise for 30 min, 5 days/week at 0 m/min (inactive groups) or 15 m/min (active groups) for 8 weeks. A TrkB receptor antagonist (ANA-12), or vehicle, was injected 2.5 h before exercise training. We measured spatial frequency and contrast sensitivity using optokinetic tracking biweekly post-STZ; retinal function using electroretinography at 4 and 8 weeks; and cognitive function and exploratory behaviour using Y-maze at 8 weeks. Retinal neurotrophin-4 was measured using ELISA. Compared with non-diabetic controls, diabetic rats showed significantly reduced spatial frequency and contrast sensitivity, delayed electroretinogram oscillatory potential and flicker implicit times and reduced cognitive function and exploratory behaviour. Exercise interventions significantly delayed the appearance of all deficits, except for exploratory behaviour. Treatment with ANA-12 significantly reduced this protection, suggesting a TrkB-mediated mechanism. Despite this, no changes in retinal neurotrohin-4 were observed with diabetes or exercise. Exercise protected against early visual and cognitive dysfunction in diabetic rats, suggesting that exercise interventions started after hyperglycaemia diagnosis may be a beneficial treatment. The translational potential is high, given that exercise treatment is non-invasive, patient controlled and inexpensive.

The RNA-binding protein, ZC3H14, is required for proper poly(A) tail length control, expression of synaptic proteins, and brain function in mice

A number of mutations in genes that encode ubiquitously expressed RNA-binding proteins cause tissue specific disease. Many of these diseases are neurological in nature revealing critical roles for this class of proteins in the brain. We recently identified mutations in a gene that encodes a ubiquitously expressed polyadenosine RNA-binding protein, ZC3H14 (Zinc finger CysCysCysHis domain-containing protein 14), that cause a nonsyndromic, autosomal recessive form of intellectual disability. This finding reveals the molecular basis for disease and provides evidence that ZC3H14 is essential for proper brain function. To investigate the role of ZC3H14 in the mammalian brain, we generated a mouse in which the first common exon of the ZC3H14 gene, exon 13 is removed (Zc3h14Δex13/Δex13) leading to a truncated ZC3H14 protein. We report here that, as in the patients, Zc3h14 is not essential in mice. Utilizing these Zc3h14Δex13/Δex13mice, we provide the first in vivo functional characterization of ZC3H14 as a regulator of RNA poly(A) tail length. The Zc3h14Δex13/Δex13 mice show enlarged lateral ventricles in the brain as well as impaired working memory. Proteomic analysis comparing the hippocampi of Zc3h14+/+ and Zc3h14Δex13/Δex13 mice reveals dysregulation of several pathways that are important for proper brain function and thus sheds light onto which pathways are most affected by the loss of ZC3H14. Among the proteins increased in the hippocampi of Zc3h14Δex13/Δex13 mice compared to control are key synaptic proteins including CaMK2a. This newly generated mouse serves as a tool to study the function of ZC3H14 in vivo.

Whole-eye electrical stimulation therapy preserves visual function and structure in P23H-1 rats

Low-level electrical stimulation to the eye has been shown to be neuroprotective against retinal degeneration in both human and animal subjects, using approaches such as subretinal implants and transcorneal electrical stimulation. In this study, we investigated the benefits of whole-eye electrical stimulation (WES) in a rodent model of retinitis pigmentosa. Transgenic rats with a P23H-1 rhodopsin mutation were treated with 30 min of low-level electrical stimulation (4 μA at 5 Hz; n = 10) or sham stimulation (Sham group; n = 15), twice per week, from 4 to 24 weeks of age. Retinal and visual functions were assessed every 4 weeks using electroretinography and optokinetic tracking, respectively. At the final time point, eyes were enucleated and processed for histology. Separate cohorts were stimulated once for 30 min, and retinal tissue harvested at 1 h and 24 h post-stimulation for real-time PCR detection of growth factors and inflammatory and apoptotic markers. At all time-points after treatment, WES-treated rat eyes exhibited significantly higher spatial frequency thresholds than untreated eyes. Inner retinal function, as measured by ERG oscillatory potentials (OPs), showed significantly improved OP amplitudes at 8 and 12 weeks post-WES compared to Sham eyes. Additionally, while photoreceptor segment and nuclei thicknesses in P23H-1 rats did not change between treatment groups, WES-treated eyes had significantly greater numbers of retinal ganglion cell nuclei than Sham eyes at 20 weeks post-WES. Gene expression levels of brain-derived neurotrophic factor (BDNF), caspase 3, fibroblast growth factor 2 (FGF2), and glutamine synthetase (GS) were significantly higher at 1 h, but not 24 h after WES treatment. Our findings suggest that WES has a beneficial effect on visual function in a rat model of retinal degeneration and that post-receptoral neurons may be particularly responsive to electrical stimulation therapy.

Neuroprotective Effects of Voluntary Exercise in an Inherited Retinal Degeneration Mouse Model

PURPOSE

Our previous investigations showed that involuntary treadmill exercise is neuroprotective in a light-induced retinal degeneration mouse model, and it may act through activation of tropomyosin-related kinase B (TrkB) receptors. This study investigated whether voluntary running wheel exercise can be neuroprotective in an inheritable model of the retinal degenerative disease retinitis pigmentosa (RP), rd10 mice.

METHODS

Breeding pairs of rd10 and C57BL/6J mice were given free-spinning (active) or locked (inactive) running wheels. Pups were weaned into separate cages with their parents' respective wheel types, and visual function was tested with ERG and a virtual optokinetic system at 4, 5, and 6 weeks of age. Offspring were killed at 6 weeks of age and retinal cross-sections were prepared for photoreceptor nuclei counting. Additionally, separate cohorts of active and inactive rd10 pups were injected daily for 14 days after eye opening with a selective TrkB receptor antagonist (ANA-12) or vehicle solution and assessed as described above.

RESULTS

Mice in the rd10 active group exhibited significant preservation of visual acuity, cone nuclei, and total photoreceptor nuclei number. Injection with ANA-12 precluded the preservation of visual acuity and photoreceptor nuclei number in rd10 mice.

CONCLUSIONS

Voluntary running partially protected against the retinal degeneration and vision loss that otherwise occurs in the rd10 mouse model of RP. This protection was prevented by injection of ANA-12, suggesting that TrkB activation mediates exercise's preservation of the retina. Exercise may serve as an effective, clinically translational intervention against retinal degeneration.

In Vivo Imaging of Retinal Oxidative Stress Using a Reactive Oxygen Species-Activated Fluorescent Probe

PURPOSE

In vivo methods for detecting oxidative stress in the eye would improve screening and monitoring of the leading causes of blindness: diabetic retinopathy, glaucoma, and age-related macular degeneration.

METHODS

To develop an in vivo biomarker for oxidative stress in the eye, we tested the efficacy of a reactive oxygen species (ROS)-activated, near-infrared hydrocyanine-800CW (H-800CW) fluorescent probe in light-induced retinal degeneration (LIRD) mouse models. After intravitreal delivery in LIRD rats, fluorescent microscopy was used to confirm that the oxidized H-800CW appeared in the same retinal layers as an established ROS marker (dichlorofluorescein).

RESULTS

Dose-response curves of increasing concentrations of intravenously injected H-800CW demonstrated linear increases in both intensity and total area of fundus hyperfluorescence in LIRD mice, as detected by scanning laser ophthalmoscopy. Fundus hyperfluorescence also correlated with the duration of light damage and functional deficits in vision after LIRD. In LIRD rats with intravitreal injections of H-800CW, fluorescent labeling was localized to photoreceptor inner segments, similar to dichlorofluorescein.

CONCLUSIONS

Hydrocyanine-800CW detects retinal ROS in vivo and shows potential as a novel biomarker for ROS levels in ophthalmic diseases.

ON pathway mutations increase susceptibility to form-deprivation myopia

The ON pathway mutation in nob mice is associated with altered refractive development, and an increased susceptibility to form-deprivation (FD) myopia. In this study, we used mGluR6-/- mice, another ON pathway mutant, to determine whether the nob phenotype was due to the Nyx mutation or abnormal ON pathway transmission. Refractive development under a normal visual environment for mGluR6-/- and age-matched wild-type (WT) mice was measured every 2 weeks from 4 to 16 weeks of age. The response to monocular FD from 4 weeks of age was measured weekly in a separate cohort of mice. Refraction and ocular biometry were obtained using a photorefractor and optical coherence tomography. Retinas were harvested at 16 weeks, and analyzed for dopamine (DA) and DOPAC using high-performance liquid chromatography. Under normal conditions, mGluR6-/- mice were significantly more myopic than their WT controls (refraction at 12 weeks; WT: 9.40 ± 0.16 D, mGluR6-/-: 6.91 ± 0.38 D). Similar to nob mice, two weeks of FD resulted in a significant myopic shift of -5.57 ± 0.72 D in mGluR6-/- mice compared to -1.66 ± 0.19 D in WT animals. No significant axial length changes were observed with either normal or FD visual conditions. At 16 weeks, mGluR6-/- retinas showed significantly lower DOPAC levels (111.2 ± 33.0 pg/mg) compared to their WT counterparts (197.5 ± 11.2 pg/mg). Retinal DA levels were similar between the different genotypes. Our results indicate that reduced retinal DA metabolism/turnover may be associated with increased susceptibility to myopia in mice with ON pathway defect mutations.