Factors influencing axial elongation in myopic children using overnight orthokeratology.

Several factors influence axial length in children with myopia treated using overnight orthokeratology. To identify these factors, this retrospective study collected axial length and corneal aberration data on 78 eyes before and 1-year after orthokeratology. Patients were divided according to axial elongation (cut-off, 0.25 mm/year). Baseline characteristics included age, sex, spherical equivalent refraction, pupil diameter, axial length, and orthokeratology lens type. Corneal shape effects were compared through tangential difference maps. Group differences in higher-order aberrations of a 4 mm zone were compared at baseline and 1-year following therapy. Binary logistic regression analysis was conducted to identify the variables determined for axial elongation. Significant differences between both groups included the initial age of wearing orthokeratology lenses, type of orthokeratology lens, size of central flattening area, corneal total surface C12 (1-year), corneal total surface C8 (1-year), corneal total surface spherical aberration (SA) (1-year root mean square [RMS] values), change in total corneal surface C12, and change in front and total corneal surface SA (RMS values). The age when wearing an orthokeratology lens was the most important factor influencing axial length in children with orthokeratology-treated myopia, followed by lens type and change in the C12 of the total corneal surface.

Synergistic effects of defocus-incorporated multiple segments and atropine in slowing the progression of myopia.

Myopia is a leading cause of visual impairment in young people worldwide. It sometimes increases the risk of blindness and reduces life quality. Previous reports have revealed the treatment effects of defocus-incorporated multiple segments (DIMS) and topical atropine (ATP) on myopia control. However, no study has evaluated these two interventions together. In this retrospective study, we aimed to determine whether the combination of DIMS lenses and 0.01% ATP can slow the progression of myopia compared with DIMS lenses or single vision (SV) lenses alone. We included 107 children with myopia who were treated with DIMS and 0.01% ATP combination (DIMS + ATP group), DIMS monotherapy (DIMS group), or a control group (SV group). We compared treatment effects among three groups in axial length and myopia progression. After a 1-year follow-up, the DIMS + ATP group showed a smaller change in axial length and myopia progression than the DIMS and SV groups (P < 0.05). Hence, combination treatment with DIMS and 0.01% ATP might be a better choice for children with myopia.

Red light irradiation as an intervention for myopia.

Myopia is one of the main causes of visual impairment worldwide. Preventing myopia and providing myopia-related interventions are of paramount importance. Based on a thorough review of the available literature, we conclude that red light irradiation can produce hyperopia, resulting in myopia prevention and control. Further, we suggest that red light irradiation may be a powerful tool for myopia prevention and control in the future. At the same time, red light has a protective effect on the cornea and retina at the cellular level, suggesting that red light irradiation may be a safe and effective modality for delaying myopia. Therefore, this form of irradiation is expected to play an important role in the prevention and control of myopia. However, more studies are needed to enhance the current state of knowledge and inform medical guidelines more comprehensively.

Retardation of Myopia by Multifocal Soft Contact Lens and Orthokeratology: A 1-Year Randomized Clinical Trial.

OBJECTIVES: This randomized, single-blind, clinical trial compared the effectiveness of multifocal soft contact lenses (MFSCLs), orthokeratology contact lenses (Ortho-kCLs), and single vision spectacles (SVSs) for myopia control. METHODS: Sixty-six eligible Chinese subjects, aged 7 to 15 years old with cycloplegic refraction measurements between -1.00 and -8.00 diopters (D), astigmatism not more than 1.00 D, and no history of myopia control treatment, were randomly assigned to wear MFSCLs, Ortho-kCLs, or SVSs for 1 year. For all three groups, baseline measurements of cycloplegic refraction, axial length (AL), and corneal endothelial cell density (CECD) were made. At the 6- and 12-month follow-up visits, changes in cycloplegic refraction, AL, and CECD were measured in the MFSCL and SVS groups. For the Ortho-kCL group, only changes in the AL were measured at 6 and 12 months, and CECD was measured at the 12-month follow-up visit. RESULTS: After 1 year of lens wear, myopia progression of the SVS group, -0.938±0.117 D, was greater than that of the MFSCLs group, -0.591±0.106 D (P=0.032). Thus, MFSCLs reduced the rate of myopia progression by 37.0% compared with the SVSs. The AL elongations after 1 year were 0.30±0.03 mm for MFSCLs (P=0.027 vs SVSs), 0.31±0.04 mm for Ortho-kCLs (P=0.049 vs SVSs), and 0.41±0.04 mm for SVSs. Compared with the SVS group, the reduction in AL elongation was 26.8% and 24.4% in the MFSCL and Ortho-kCL groups, respectively. There were no significant differences in CECD among the three groups (P>0.05). CONCLUSIONS: Compared with SVSs, wearing MFSCLs and Ortho-kCLs significantly delayed myopia progression. MFSCLs and Ortho-kCLs are safe and promising methods of myopia control (chictr.org number, ChiCTR2100048452).

Mapping research trends of chronic ocular graft-versus-host disease from 2009 to 2020: a bibliometric analysis.

PURPOSE: To evaluate the global scientific output of research on ocular chronic Graft versus host disease (cGVHD) and explore the current status and trends in this field over the past decade by bibliometric analysis. METHODS: The bibliometric search was performed in the Web of Science Core Collection (WoSCC) database. VOSviewer v.1.6.16 was used to map the knowledge domain. The annual number of publications and citations, distribution of countries and organizations, productivity of authors and journals, international collaborations, cited references, and keywords in the field of ocular cGVHD were visualized. RESULTS: In total, 398 peer-reviewed publications from 2009 to 2020 on ocular cGVHD were retrieved. The United States among all countries had the highest number of publications and citations, and Keio University was the most effective institution. Dana, R ranks the highest regarding the number of publications and citations on ocular cGVHD. Cornea and Biology of Blood and Marrow Transplantation were the most-cited journals in ocular cGVHD studies from ophthalmology and hematology, respectively. The top-cited references were primarily centered on dry eye. The keywords constituted three clusters: (1) consensus criteria and epidemiology of ocular cGVHD, (2) preclinical medical research of ocular cGVHD, and (3) treatment. CONCLUSION: Based on the data retrieved from WoSCC, a comparative analysis of the quantity and quality of papers on ocular cGVHD was conducted through bibliometric methods. This may contribute to better understanding of the status of ocular cGVHD study. The three major research topics shed new light on the ocular cGVHD study as well as meaningful materials for scholars to identify potential collaborators and promising partner institutions.

Machine learning for predicting the treatment effect of orthokeratology in children.

Purpose: Myopia treatment using orthokeratology (ortho-k) slows myopia progression. However, it is not equally effective in all patients. We aimed to predict the treatment effect of ortho-k using a machine-learning-assisted (ML) prediction model. Methods: Of the 119 patients who started ortho-k treatment between January 1, 2019, and January 1, 2022, 91 met the inclusion criteria and were included in the model. Ocular parameters and clinical characteristics were collected. A logistic regression model with least absolute shrinkage and selection operator regression was used to select factors associated with the treatment effect. Results: Age, baseline axial length, pupil diameter, lens wearing time, time spent outdoors, time spent on near work, white-to-white distance, anterior corneal flat keratometry, and posterior corneal astigmatism were selected in the model (aera under curve: 0.949). The decision curve analysis showed beneficial effects. The C-statistic of the predictive model was 0.821 (95% CI: 0.815, 0.827). Conclusion: Ocular parameters and clinical characteristics were used to predict the treatment effect of ortho-k. This ML-assisted model may assist ophthalmologists in making clinical decisions for patients, improving myopia control, and predicting the clinical effect of ortho-k treatment via a retrospective non-intervention trial.

High performance OCTA enabled by combining features of shape, intensity, and complex decorrelation.

Motion contrast optical coherence tomography angiography (OCTA) entails a precise identification of dynamic flow signals from the static background, but an intermediate region with voxels exhibiting a mixed distribution of dynamic and static scatterers is almost inevitable in practice, which degrades the vascular contrast and connectivity. In this work, the static-dynamic intermediate region was pre-defined according to the asymptotic relation between inverse signal-to-noise ratio (iSNR) and decorrelation, which was theoretically derived for signals with different flow rates based on a multi-variate time series (MVTS) model. Then the ambiguous voxels in the intermediate region were further differentiated using a shape mask with adaptive threshold. Finally, an improved OCTA classifier was built by combining shape, iSNR, and decorrelation features, termed as SID-OCTA, and the performance of the proposed SID-OCTA was validated experimentally through mouse retinal imaging.

The relationship between major intrinsic protein genes and cataract.

BACKGROUND: Genetic factors play an essential role in the development of cataracts, and the major intrinsic protein (MIP) gene is a type of causative genes. Our study aims to discuss the current research progress of MIP genes responsible for cataractogenesis in DNA and protein levels, which is essential in achieving a response to the molecular deficiencies and pathophysiologic features of cataract. METHODS: We developed a search strategy using a combination of the words "Cataract", "Mutation", "MIP gene", and "AQP0" to identify all articles from PubMed, Web of Science, Scopus, and Google Scholar up to December 2019. To find more articles and to ensure that databases were thoroughly searched, the reference lists of selected items were also reviewed. RESULTS: A total of 29 MIP gene mutations causing congenital cataract were obtained by searching these databases and analyzing the results of genetic mutation pathogenicity prediction software tools; most of them caused amino acid codon changes in the H4, H5, H6, C-TIDs, and loop C in the structure of the MIP protein. However, there was no clear causality between lens morphology, phenotypes, and genotypes. The genotype TC in polymorphism c.-4T > C and haplotype CCG of rs2269348, c.-4T > C, and rs74641138 in MIP may attach an additional genetic risk factor for age-related cataract. CONCLUSION: These single-base mutations and single nucleotide polymorphisms might be importantly involved in the pathogenesis of congenital cataract and age-related cataract, respectively. This review provides a significant reference for clinical trials and theoretical studies.

Optical Coherence Tomography Angiography in Pinguecula and Pterygium.

PURPOSE: To investigate the density of conjunctival blood vessels in normal eyes and in eyes with pinguecula or pterygium. METHODS: In this cross-sectional study, the conjunctival blood vessel density of 15 normal eyes, 15 pinguecula eyes, and 15 pterygium eyes of 43 healthy adults was assessed using optical coherence tomography angiography with an anterior segment lens adapter. The nasal surface of each eye (3 × 3 mm) was scanned 3 times to a depth of 800 µm. Conjunctival vessel density was defined as the percent of the scanned volume occupied by vessels in which blood flow was measured. RESULTS: The high reliability of data measurement was supported by good coefficients of repeatability (<10%) of the image quality score and high intraclass correlation coefficients (>0.9). The vessel density in normal conjunctivas, 52.2 ± 4.1%, was similar to that in pinguecula conjunctivas, 50.5 ± 4.7% (P = 0.3006). However, the vessel density in conjunctivas with pterygium, 63.6 ± 3.7%, was greater than that in either normal (P < 0.0001) or pinguecula (P < 0.0001) conjunctivas. CONCLUSIONS: Using optical coherence tomography angiography with an anterior segment lens adapter, the ocular surface blood vessel density was imaged and assessed with good repeatability and reliability. The blood vessel density of conjunctivas with pterygium was significantly greater than that in either normal or pinguecula conjunctivas. This suggests that, in contrast to pinguecula development, pterygium development includes angiogenesis and neovascularization.

Repeatability of ocular surface vessel density measurements with optical coherence tomography angiography.

BACKGROUND: To determine the repeatability of measurements of ocular surface vessel density in normal and diseased eyes using optical coherence tomography angiography (OCTA). METHODS: Ten normal eyes, 10 pinguecula eyes, and 10 pterygium eyes of 30 volunteers were subjected to OCTA (AngioVue Imaging System, Optovue, Inc.). For scanning, we used the corneal adapter module. Each eye was scanned three times in the nasal and temporal directions, separately. AngioVue software was used to generate the ocular surface vessel density. Ocular surface vessel density was defined as the proportion of vessel area with blood flow to the total measurement area (3 × 3 mm2). Intersession repeatability of the measurement was summarized as the coefficient of variation (CV), and intraclass correlation coefficients (ICC) were calculated by variance component models. RESULTS: The CVs were less than 5% in all subjects, and the ICCs exceeded 0.9; thus, all measurements showed good repeatability. The nasal vessels densities differed significantly between healthy eyes and eyes with pterygium (P < 0.05); however, there was no significant difference between healthy eyes and eyes with pinguecula (P = 0.466). CONCLUSIONS: These results suggest that measurement of ocular surface vessel density by OCTA in normal eyes and eyes with pterygium and pinguecula is repeatable. This preliminary research describes a quantitative and visual method for assessing vessel density of the ocular surface with a high level of consistency.

Anterior Segment Biometry with Phenylephrine and Tropicamide during Accommodation Imaged with Ultralong Scan Depth Optical Coherence Tomography.

PURPOSE: To investigate the influence of phenylephrine and tropicamide on anterior segment biometry with ultralong scan depth optical coherence tomography (UL-OCT) during accommodation. METHODS: In this study, 20 left eyes of healthy volunteers with a mean ± standard deviation age of 31.05 ± 5.84 years and a mean refraction of -1.16 ± 1.11 diopters (range 0∼-3.0 D) were imaged using UL-OCT after instillation of artificial tears, phenylephrine, and tropicamide in three follow-up trials, respectively. At each follow-up trial, two repeated measurements were performed at states of relax and 5D accommodative stimulation. The dimensional parameters included central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter (PD), lens thickness (LT), and horizontal radii of the lens anterior and posterior surface curvatures (LAC and LPC). RESULTS: Tropicamide led to larger pupil, deeper ACD, thinner LT, and flatter crystalline lens surface (P < 0.05). Phenylephrine induced an increase in PD (P < 0.05), while no significant changes were seen in ACD, LT, LAC, and LPC (P > 0.05). CCT did not change after both phenylephrine and tropicamide instillation in this study (P > 0.05). Tropicamide induced the loss of accommodation and phenylephrine achieved pupil dilation without affecting the accommodation. PD, ACD decreased, LT increased significantly and the anterior and posterior surface of the lens in a 6.294 mm of diameter optical zone became steeper during accommodation after administration of phenylephrine (P < 0.05). CONCLUSION: The anterior segment physiology changed after tropicamide instillation. Besides, tropicamide induced the loss of accommodation and phenylephrine preserved the accommodation with a larger pupil. And, the anterior and posterior surface of lens in a 6.294 mm of diameter optical zone became steeper during the accommodation.

Analysis of amino acids in human tears by hydrophilic interaction liquid chromatography and quadrupole orbitrap mass spectrometry.

Amino acids in human tears play certain physiological roles and their determination is challenging due to complicated chemical properties. This study described a fast and sensitive method for the simultaneous determination of 15 amino acids (AAs) in tears by hydrophilic interaction liquid chromatography and quadrupole orbitrap mass spectrometry (HILIC-Q-Orbitrap-MS). Amino acids in tears were extracted by methanol, and then cleaned up with a solid phase extraction (SPE) cartridge. Chromatographic separation was performed on a 1.7 µm BEH Amide column within 8 min. Tear samples spiked with free AAs were tested in terms of linearity, sensitivity, repeatability, and recovery. Two stable isotope-labeled amino acids were used as internal standards to improve the method performance. Recoveries for all analytes ranged from 89 to 107%. Intra-day and inter-day precision, expressed as relative standard deviations, were all below 10%, and the method detection limits ranged from 0.02 µmol L-1 to 0.11 µmol L-1. The developed method with high throughput and high analyte specificity shows good promise for consistent analysis of free amino acids in tears.

The use of in-strip digestion for fast proteomic analysis on tear fluid from dry eye patients.

Tear is an accessible fluid for exploring biomarkers of dry eye disease. This study describes a fast proteomic method by LC-Q-orbitrap-MS analysis with in-strip digestion and investigates the tear proteome of dry eye patients. Schirmer's strips were used for collection of tear fluid from patients. These strips were cut into pieces and directly digested with trypsin before mass spectrometry analysis. The data showed that more than 50 proteins were found in tear fluid from dry eye patients. Gene Ontology (GO) annotation showed that most of proteins were transfer/carrier proteins, hydrolyses, enzyme modulators and signaling molecules. Targeted proteomics strategy revealed that 18 proteins were differentially expressed in dry eye patients. Furthermore, it was showed that the common post-translational modification in tear proteins is deamidation of Asn.

A Head-Mounted Spectacle Frame for the Study of Mouse Lens-Induced Myopia.

The mouse model has been widely employed to explore the mysteries of myopia. For now, existing techniques for induction of experimental myopia in mice can be classified into three types: (1) devices directly glued to the fur; (2) devices attached using a combination of glue and sutures; (3) devices attached using a skull-mounted apparatus. These techniques each have its advantages, disadvantages when considering the devices stability, safety, complexity, effectiveness, and so forth. Thus, techniques for myopia induction in mice have yet to be further refined to popularize the applications. In this pilot study, we introduce a new head fixation device named the head-mounted spectacle frame apparatus for the study of mouse lens-induced myopia. Surgical procedures for device attachment were relatively simple and easy to learn in our study. Effective myopia induction was validated by retinoscopy refraction and axial length measurement using optical coherence tomography. In addition, it showed improved compliance and reliable safety when compared to the published methods. The head-mounted spectacle frame apparatus provides a new choice for the study of lens-induced myopia in mouse. It also allows for the use of form deprivation, making it attractive for future experimental mouse myopia trials.

Ocular Trauma Score in Siderosis Bulbi With Retained Intraocular Foreign Body.

The purpose of this study was to investigate the clinical characteristic and visual outcome of siderosis bulbi with retained intraocular foreign body (IOFB) and to validate the predictive value of the Ocular Trauma Score (OTS) in siderosis bulbi. Certain numerical values rendered to the OTS variables at present were summated (Table 1) and converted into 5 OTS categories as performed in the OTS study. The prognostic value of OTS was first assessed in cases of siderosis bulbi resulting from a chemical reaction of retained IOFBs. Twenty-four eyes of 24 patients diagnosed with siderosis bulbi who underwent surgery between 2007 and 2013 at our medical centre were reviewed. Due to patients' ignorance in ocular injuries, delayed presentation by the patient (54.17%) and no history of trauma (16.67%) were the most common cause of siderosis bulbi with IOFB retention. The main symptom of all these patients was impaired vision. The most common complications were cataract (23/24, 95.83%), followed by retinal pigmentary degeneration (15/22, 68.18%), iris heterochromia (14/24, 58.33%), pupillary mydriasis (10/21, 47.62%), secondary glaucoma (6/24, 25.00%), relative afferent pupillary defect (6/24, 25.00%), and retinal detachment (3/24, 12.50%). IOFBs were removed in 22 eyes (91.67%), except 2 enucleated eyes with absolute glaucoma (8.33%). Among all the patients (24 eyes), the best-corrected visual acuity improved in 63.64%, unchanged in 18.18% and deteriorated in 18.18% after surgical intervention. No statistically significant difference was found between the categorical distributions of our patients and those in the OTS study group. Further promotion and education on eye protection are needed to minimize visual loss from siderosis bulbi. The OTS, which was designed to predict visual outcomes of general ocular trauma, may also provide reliable information about the prognosis of siderosis bulbi resulting from a chemical reaction of retained IOFBs.

Assessment of Full-Eye Response to Osmotic Stress in Mouse Model In Vivo Using Optical Coherence Tomography.

NaCl based solutions were applied as osmotic stress agents to alter the hydration state of the mouse eye. Full-eye responses to these osmotic challenges were monitored in vivo using a custom-built optical coherence tomography (OCT) with an extended imaging range of 12.38 mm. Dynamic changes in the mouse eye were quantified based on the OCT images using several parameters, including the central corneal thickness (CCT), the anterior chamber depth (ACD), the crystalline lens thickness (LT), the cornea-retina distance (CRD), the iris curvature (IC), and the lens scattering intensity (LSI). Apparent but reversible changes in the morphology of almost all the ocular components and the light transparency of the lens are exhibited. Particularly, the ocular dehydration induced by the hypertonic challenges resulted in a closing of the iridocorneal angle and an opacification of the lens. Our results indicated that the ocular hydration is an important physiological process which might be correlated with various ocular disorders, such as dry eye, cataract, and angle-closure glaucoma, and would affect the biometry and imaging of the eye. OCT uniquely enables the comprehensive study of the dynamic full-eye responses to the ocular hydration in vivo.

Two kinds of ocular trauma score for paediatric traumatic cataract in penetrating eye injuries.

PURPOSE: To compare the ocular trauma score (OTS) and the paediatric penetrating ocular trauma score (POTS) as prognostic model for visual outcome in paediatric traumatic cataract cases after penetrating eye injuries. METHODS: All children younger than 16 years with unilateral traumatic cataract following penetrating trauma between 2007 and 2012 were retrospectively reviewed. Univariate chi-square analysis was conducted to identify the variables associated with profound visual loss. The area under the receiver-operating characteristic curves (AUROC) was used to assess the predictive ability of the two models. RESULTS: The study group comprised 65 boys and 37 girls. The variables associated with profound visual loss were: a relative afferent papillary defect (RAPD) (P<0.001), poor initial vision (P=0.01), vitreous haemorrhage (P<0.001), retinal detachment (P<0.001), posterior penetrating site (P<0.001), hyphema (P<0.001), no intraocular len implantation (P<0.001) and endophthalmitis (P=0.001). OTS could not be calculated in 21 patients (20.6%) without clinical data on initial visual acuity and RAPD. For the patients with complete clinical data, POTS was similar to OTS in predicting poor vision (AUROC 0.904 vs 0.924) and in predicting good vision (AUROC 0.766 vs 0.736). For all the samples, POTS was a robust predictor of poor vision (AUROC 0.910) and had a moderate ability to predict good vision (AUROC 0.764). CONCLUSION: OTS has high ability to predict visual outcome for paediatric traumatic cataract following penetrating ocular trauma. POTS is also a reliable prognostic model for very young child without initial vision or RAPD, but is only for penetrating eye injuries.

Visualization of the ocular pulse in the anterior chamber of the mouse eye in vivo using phase-sensitive optical coherence tomography.

We report on a phase-based method for accurately measuring the ocular pulse in the anterior chamber in vivo. Using phase-sensitive optical coherence tomography with optimized scanning protocols and equations for compensating bulk motion and environmental vibrations, a high sensitivity of 0.9 µm/s minimal velocity is demonstrated at a wide detection band of 0 to 380 Hz. The pulsatile relative motion between cornea and crystalline lens in rodents is visualized and quantified. The relative motion is most likely caused by respiration (1.6 Hz) and heartbeat (6.6 Hz). The velocity amplitude of the relative motion is 10.3 ± 2.4 µm/s. The displacement amplitudes at the respiratory and cardiac frequencies are 202.5 ± 64.9 and 179.9 ± 49.4 nm, respectively. The potential applications the measurement technique can be found in the evaluation of intraocular pressure and the measurement of biomechanical properties of the ocular tissue, which are important in several ocular diseases.