Retinal and choroidal structure and vascularity in Chinese emmetropic and myopic children.

PURPOSE: This study evaluated the structural features of the retinal and choroidal regions and their correlations with ocular biometric and vascular parameters in Chinese children using optical coherence tomography angiography (OCTA). METHODS: A total of 159 children, 6-13 years of age, were included in this prospective study. The sample consisted of 55 emmetropes (spherical equivalent ≤ +0.75 and > -0.50 D), 53 low-moderate myopes (≤ -0.50 to > -6.00 D) and 51 high myopes without pathological changes (≤ -6.00 D). Optical coherence biometry was used to measure axial length (AL) and anterior segment parameters. Swept-source optical coherence tomography/OCTA was used to assess the macular structures and vascular characteristics in a 6 × 6 mm region centred on the macula. RESULTS: In a comprehensive analysis adjusting for age, sex, AL, macular blood perfusion, intraocular pressure and anterior segment parameters, retinal thickness (RT) showed a significant positive association with deep retinal vascular density and superficial retinal vascular density in the foveal area, but not with AL. Moreover, RT exhibited a significant negative association with AL in the parafoveal and perifoveal regions. Further, a significant positive correlation was observed between choroidal thickness and both choroidal vascular volume and choriocapillaris perfusion area, along with a negative correlation with AL across the entire macular region. CONCLUSIONS: This study showed that the thickness of retina and choroid in Chinese children was not only associated with AL but also showed dynamic properties such as the blood perfusion of the retina and choroid, particularly in the foveal area.

The Effects of Repeated Low-Level Red-Light Therapy on the Structure and Vasculature of the Choroid and Retina in Children with Premyopia.

INTRODUCTION: The purpose of this study was to explore the effects of repeated low-level red-light (RLRL) therapy on the structure and vasculature of the choroid and retina in Chinese children with premyopia. METHODS: This study was a single-center randomized clinical trial. A total of 94 children with premyopia (- 0.50 D < spherical equivalent [SE] ≤ + 0.75 D) were randomly assigned to either the RLRL therapy or control group. Follow-up visits were planned at 1, 3, 6, 9, and 12 months. Optical coherence biometry was used to measure axial length (AL) and anterior segment parameters. Choroidal thickness (CT), retinal thickness (RT), superficial retinal vascular density (SRVD), deep retinal vascular density (DRVD), choriocapillaris perfusion area (CCPA), and choroidal vessel volume (CVV) were measured by optical coherence tomography angiography, centered on the foveal, parafoveal (ParaF), and perifoveal (PeriF) regions. RESULTS: The thickening of the choroid was observed across the entire macular region at different time points in the RLRL therapy group. Relative to the baseline measurement, foveal CT significantly increased at the 1-month follow-up with RLRL therapy, with a mean (± standard deviation [SD]) adjusted change of 16.96 ± 19.87 µm. The greatest magnitude of foveal CT changes was observed at the 3-month visit (an increase of 19.58 ± 20.59 µm), with a slight reduction in the extent of foveal CT increase at the 6-month visit (an increase of 15.85 ± 23.77 µm). The second greatest CT increase was observed at the 9-month visit (an increase of 19.57 ± 35.51 µm), after which the extent of CT increase gradually decreased until the end of the study at the 12-month visit (an increase of 11.99 ± 32.66 µm). We also observed a significant increase in CT in the ParaF and PeriF areas in the RLRL group over 12 months. In contrast, CT across the entire macular region in the control group significantly decreased throughout the follow-up visits (all P < 0.05). Regarding the vascular parameters of the choroid, significant increases in CVV were observed primarily in the ParaF and PeriF regions of the choroid in the RLRL group. In comparison, the control group exhibited decreases in CVV throughout the entire area. Furthermore, notable elevations in CCPA were detected in the PeriF area of the choroid in the RLRL group during the 1-month (an increase of 0.40 mm2), 3-month (an increase of 0.25 mm2), and 12-month visits (an increase of 0.42 mm2) (all P < 0.05). In addition, no notable differences were observed between the groups regarding foveal RT and retinal vascular parameters throughout the 12 months (P > 0.05). Notably, RLRL therapy achieved a notable reduction in SE shift by 73.8%, a substantial decrease in AL change by 67.9%, and a significant reduction in myopia incidence by 45.1% within 1 year. CONCLUSION: Our study demonstrated a significant increase in CT and flow in the RLRL-treated eyes throughout the 12-months of the study. Combined with its reduction in spherical equivalent progression and axial elongation, RLRL could be used as an effective therapy for preventing progression in premyopes. TRIAL REGISTRATION: ChiCTR2200062028.

Association between whole-grain intake and myopia in chinese children: a cross-sectional epidemiological study.

BACKGROUND: Nutritional status influences the growth and development of the eyes. However, there are few studies on the association between diet, especially whole grains (WG) consumption, and myopia. The study aimed to evaluate the association between WG intake and myopia prevalence among primary school-age children in China. METHODS: This cross-sectional epidemiological study conducted between November 2019 and December 2019 included 586 children, aged 6-12 years, attending primary school in Binhai district, Tianjin, China. Ophthalmologic examinations and optometric cycloplegic refraction measurements were conducted. Information was collected on known risks and protective factors for myopia and the consumption of WGs, vegetables, and fruits. This association between the probability of myopia and the proportion of WG consumption (WG proportion was calculated as the mean intake from WG sources divided by total grain intake), adjusted for protective and risk factors, was analysed using crude and multivariable logistic regression. RESULTS: Among the study participants, 226/586 (38.57%) children had myopia in at least one eye. WG intake was inversely correlated with the prevalence of myopia. Furthermore, in the multivariate analysis, WG intake of > 50% was identified as a protective factor against myopia after subsequent adjustment for children's age, sex, parental myopia, near-work activity, screen time, reading and writing habits, visual fatigue, outdoor time, and classroom light environment (all P < 0.05). CONCLUSION: WG intake (> 50%) was an independent protective factor against myopia. Modifying the form of grains consumed (whole versus refined) could be one of the targets of future public health measures.

A comparison of vision-related quality of life between Defocus Incorporated Soft Contact (DISC) lenses and single-vision spectacles in Chinese children.

OBJECTIVE: This study aimed to compare the vision-related quality of life (VRQoL) between Defocus Incorporated Soft Contact (DISC) lenses and single-vision spectacles in Chinese children, in order to evaluate their visual performance and subjective acceptance of this bifocal designed contact lenses treatment. METHODS: Chinese participants aged 7 to 12 years, with myopia of -4.00 to -0.75 D, astigmatism < 1.50 D, and monocular best-corrected visual acuity 0.0 or better, were recruited in the study. All participants had been wearing DISC lenses, or single-vision spectacles, for the last 6 to 18 months and were requested to complete the routine ocular examination and Chinese version of the Pediatric Refractive Error Profile (PREP 2) questionnaire. The questionnaire consisted of 7 scales: vision, symptoms, appearance, activities, handling, peer perception, and overall score. According to their habitual correction modalities, fifty-four children were allocated to the DISC group and 56 to the single-vision spectacles group. A generalized linear model was fitted to assess variables associated with the PREP 2 score. RESULTS: Participants wearing DISC lenses scored significantly higher than those wearing single-vision spectacles for vision, appearance, activities, peer perception, and overall (all P < 0.05). The improvement of VRQoL in the DISC group was mainly represented in appearance, peer perception, and activities. The quality of life improved more for older participants on scales of vision, symptoms, handling, appearance, and overall score (all P < 0.05). The interaction between treatment and age was statistically significant for the activities scale (P < 0.05). CONCLUSION: DISC lens wear significantly improves VRQoL in Chinese children compared with single-vision spectacles for most of the survey scales, especially in the areas of appearance, peer perception, and activities. The benefits provided by DISC lenses contribute to greater satisfaction than single-vision spectacles for myopic children.

The Chinese version of the Pediatric Refractive Error Profile2 (PREP2): Translation, validation and reliability.

OBJECTIVE: This study aimed to develop and evaluate an adapted Chinese version of the Pediatric Refractive Error Profile2 (PREP2) and to evaluate its acceptability, reliability, and validity in a population of Chinese children with refractive error. METHODS: The Chinese version of the PREP2 was translated using a standardized procedure and then administered to consecutive outpatients with refractive error. Reliability was assessed by the Cronbach's alpha coefficient for internal consistency and test-retest reliability. Validity of the questionnaire was assessed by item discriminant validity, construct validity, known-groups validity, and concurrent validity. RESULTS: A total of 104 subjects were recruited for the study and all completed the Chinese version of the PREP2 questionnaire with no problems. A random sample of 50 patients completed the questionnaire twice within one week. The Cronbach's alpha coefficients ranged from 0.71 to 0.89 across scales, and the intraclass correlation coefficient ranged from 0.86 to 0.92, indicating excellent internal consistency and test-retest reliability. The item-scale correlation coefficients between the items and the corresponding scales ranged from 0.39 to 0.88. The translated questionnaire had good discriminatory power between contact lens wearers and spectacle wearers. Significant correlations were found between the scales and traditional clinical parameters, such as spherical equivalent and uncorrected visual acuity, showing good construct and concurrent validity. CONCLUSION: The Chinese version of the PREP2 exhibited good internal consistency, test-retest reliability, item-scale correlation, discriminatory power, construct validity, and concurrent validity. Therefore, it may be adopted as an acceptable, reliable, and valid instrument for the measurement of vision-related quality of life in Chinese children with refractive error.

A randomized clinical trial using cyclopentolate and tropicamide to compare cycloplegic refraction in Chinese young adults with dark irises.

BACKGROUND: To evaluate the necessity of cycloplegia for epidemiological studies of refraction in Chinese young adults (aged 17-22 years) with dark irises, and to compare the cycloplegic effects of 1% cyclopentolate and 0.5% tropicamide in them. METHODS: A total of 300 young adults (108 males and 192 females) aged 17 to 22 years (mean 19.03 ± 1.01) were recruited from Tianjin Medical University from November 2019 to January 2020. Participants were randomly divided into two groups. In the cyclopentolate group, two drops of 1% cyclopentolate eye drop were administrated (one drop every 5 min), followed by autorefraction and subjective refraction 30 to 45 min later. In the tropicamide group, four drops of 1% Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) eye drop were given (one drop every 5 min), followed by autorefraction and subjective refraction 20 to 30 min later. The participants and the examiners were masked to the medication. Distance visual acuity, intraocular pressure (IOP), non-cycloplegic and cycloplegic autorefraction (Topcon KR-800, Topcon Co. Tokyo, Japan), non-cycloplegic and cycloplegic subjective refraction and ocular biometry (Lenstar LS-900) were performed. RESULTS: The values of spherical equivalent (SE) and sphere component were significantly different before and after cycloplegia in the cyclopentolate group and the tropicamide group (p < 0.05). The mean difference between noncycloplegic and cycloplegic autorefraction SE was 0.39 D (±0.66 D) in the cyclopentolate group and 0.39 D (±0.34 D) in the tropicamide group. There was no significant difference in the change of SE and sphere component after cycloplegia between the cyclopentolate group and the tropicamide group (p > 0.05). In each group, no significant difference was found between autorefraction and subjective refraction after cycloplegia (p > 0.05). We also found that more positive or less negative cycloplegic refraction was associated with the higher difference in SE in each group. CONCLUSIONS: Cycloplegic refractions were generally more positive or less negative than non-cycloplegic refractions. It is necessary to perform cycloplegia for Chinese young adults with dark irises to obtain accurate refractive errors. We suggest that cycloplegic autorefraction using tropicamide may be considered as a reliable method for epidemiological studies of refraction in Chinese young adults with dark irises. TRIAL REGISTRATION: The study was registered on September 7, 2019 (Registration number: ChiCTR1900025774 ).

Evaluation of tear film and the morphological changes of meibomian glands in young Asian soft contact lens wearers and non-wearers.

BACKGROUND: The aim of this study was to explore the differences in terms of tear film and meibomian glands (MGs) between young Asian soft contact lens (CL) wearers and non-wearers. METHODS: A prospective, cross-sectional observational study was conducted using 148 subjects (63 non-wearers, and 85 soft CL wearers who had been wearing CLs for more than 1 year) recruited from a clinic in Tianjin, China. All subjects first responded to an Ocular Surface Disease Index (OSDI) questionnaire and then underwent a standardized dry eye examination, which included measuring tear meniscus height (TMH), non-invasive tear breakup time (NIBUT), and corneal fluorescein staining (CFS). The MGs were evaluated via ImageJ, distorted MG count and the MG dropout were recorded. RESULTS: Compared to the control group (non-wearers), the CL group recorded higher OSDI and CFS scores, lower TMH and NITBUT values, a larger distorted MG count, and larger MG dropout (all P < 0.05). Pearson correlation analysis found a correlation between MG dropout and the duration of CL use (r = 0.440, P < 0.001), OSDI (r = 0.298, P = 0.006), and CFS scores (r = 0.442, P < 0.001). CONCLUSION: CL wearers showed higher MG dropout and reduced TMH and NITBUT, which likely contributes to severe CL-related dry eye symptoms. CL use may lead to a higher MG dropout rate, and the extent of the MG dropout presumably influences the tear film status in CL wearers.

Meibomian Gland Dropout, not Distortion, Can Distinguish Dry Eyes from Normal Eyes in Contact Lens Wearers.

PURPOSE: To examine the effectiveness of using meibomian gland (MG) dropout and distortion for dry eye disease (DED) diagnosis in a young population with long-term contact lens (CL) wear. METHODS: Seventy-three CL-wearers and 68 non-CL-wearers (20-28 years old) participated in the study. The diagnosis of DED was based on an ocular surface disease index ≥ 13, and a noninvasive breakup time < 10 seconds or positive corneal fluorescein staining. The MG dropout and distortion in each subject were quantified with non-invasive meibography. Receiver operating characteristic (ROC) curves were created to evaluate the effectiveness of using MG dropout and distortion to determine the presence of DED in CL-wearers and non-CL-wearers. RESULTS: In non-CL-wearers, the MG distortion was significantly higher in DED subjects than in normal subjects (3.83 ± 1.81 versus 1.59 ± 1.04). In CL-wearers, MG distortion was not significantly different (5.12 ± 4.11 versus 5.51 ± 3.15 in normal and DED subjects respectively). The area under the ROC curve (AUC) for MG distortion was 0.783 in the non-CL-wearers, but 0.507 in CL-wearers. In non-CL-wearers, MG dropout was significantly higher in DED subjects than in normal subjects (0.22 ± 0.08 versus 0.15 ± 0.06). In CL-wearers, MG dropout was also significantly higher in DED subjects than in normal subjects (0.29 ± 0.11 versus 0.22 ± 0.08). The AUC for MG dropout used to classify DED was 0.740 in the non-CL-wearers and 0.715 in CL-wearers. CONCLUSIONS: MG dropout was effective in distinguishing subjects with DED from normal subjects in both CL wearers and non-CL wearers. MG distortion can only distinguish DED subjects from normal ones in non-CL wearers, but not in CL wearers.

Fabrication and Characterization of ß-Lactoglobulin-Based Nanocomplexes Composed of Chitosan Oligosaccharides as Vehicles for Delivery of Astaxanthin.

Astaxanthin (Ax), a type of carotenoid, has limited use as a result of its poor water solubility, low bioavailability, and decomposition under harsh conditions. This study reports a delivery system for Ax through a simple affinity binding with ß-lactoglobulin and then coated with chitosan oligosaccharides. Ax-loaded ß-lactoglobulin nanocomplexes and chitosan oligosaccharide-coated nanocomplexes were successfully prepared. The nanocomplexes exhibited a smooth spherical shape with diameters of about 40 and 60 nm measured by transmission electron microscopy. Spectroscopic techniques (ultraviolet-visible, fluorescence, and Fourier transform infrared spectroscopy) combined with molecular docking were used to determine the binding mechanism of Ax and ß-lactoglobulin. In comparison to native Ax, the nanocomplexes maintain the hydroxyl radical scavenging activity of Ax under the treatment of acid, high temperature, and ultraviolet radiation. The release experiment of nanocomplexes revealed that the encapsulation could provide prolonged release of Ax in simulated gastrointestinal juices. This study aimed to fabricate and characterize Ax-ß-lactoglobulin nanocomplexes, which can improve the Ax stability and slow release.

Preparation and characterization of starch nanoparticles via self-assembly at moderate temperature.

Starch nanoparticles (SNPs) were fabricated via short glucan chains self-assembly at 50 °C and their characteristics were evaluated by transmission electron microscopy, dynamic light scattering, molecular weight distributions, X-ray diffraction, differential scanning calorimetry, and Fourier transforms infrared spectroscopy. The results showed that SNPs exhibited spherical particles with a diameter of approximately 30-40 nm. The molecular weight of the SNPs mainly distributed at degree of polymerization (DP) 12 and DP 30. The gelatinization temperature of the SNPs increased dramatically compared to that of native waxy maize starch. The crystallinity of the samples increased as the assembling time increased and showed the same A-type in the X-ray diffraction pattern as native starch. This newly proposed SNPs approach has potential application in starch nanocomposite films due to their high gelatinization temperature.