The impact of different postures on acute intraocular pressure and accommodation responses during reading.

INTRODUCTION: To investigate the effects of different reading postures on intraocular pressure (IOP) and near-work-induced transient myopia (NITM) in children with myopia. METHODS: Sixty myopic children were instructed to read a book text placed at 33 cm for 30 min with two different reading postures: head bowed and head upright postures. The participants' IOP and NITM were assessed using a rebound tonometer and an open-field autorefractor. The measurement of IOP was conducted prior to reading, during reading sessions (at 5, 10, 20, and 30-min intervals), and after a 5-min recovery period. RESULTS: For the head bowed posture, the mean baseline IOP was 16.13 ± 2.47 mmHg. A significant rise in IOP was observed after 5 min of reading (17.17 ± 2.97 mmHg; +1.03 ± 2.29 mmHg; p = 0.014). Subsequent measurements revealed a further increase after 20 min (17.87 ± 2.90 mmHg; +1.73 ± 2.58 mmHg; p < 0.001), which continued to persist even after 30 min of reading (17.57 ± 3.46 mmHg; +1.43 ± 2.66 mmHg; p = 0.002). The IOP at different time points measured in the head upright posture did not show any significant difference in comparison to the baseline measurement (all p = 1.000). Compared to reading with the head upright, reading with the head bowed resulted in a greater increase in IOP at each time point (p < 0.05). Furthermore, the NITM was higher for reading with the head bowed than for reading with head upright at 30 min (-0.24 ± 0.53 D vs. -0.12 ± 0.47 D, p = 0.038). CONCLUSION: Reading in a head bowed position resulted in greater increases in IOP and NITM compared to reading in a head upright posture.

Outdoor time influences VIPR2 polymorphism rs2071623 to regulate axial length in Han Chinese children.

Clinical relevance: Identification of individuals with a higher risk of developing refractive error under specific gene and environmental backgrounds, especially myopia, could enable more personalized myopic control advice for patients. Background: Refractive error is a common disease that affects visual quality and ocular health worldwide. Its mechanisms have not been elaborated, although both genes and the environment are known to contribute to the process. Interactions between genes and the environment have been shown to exert effects on the onset of refractive error, especially myopia. Axial length elongation is the main characteristic of myopia development and could indicate the severity of myopia. Thus, the purpose of the study was to investigate the interaction between environmental factors and genetic markers of VIPR2 and their impact on spherical equivalence and axial length in a population of Han Chinese children. Methods: A total of 1825 children aged 13~15 years in the Anyang Childhood Eye Study (ACES) were measured for cycloplegic autorefraction, axial length, and height. Saliva DNA was extracted for genotyping three single-nucleotide polymorphisms (SNPs) in the candidate gene (VIPR2). The median outdoor time (2 h/day) was used to categorize children into high and low exposure groups, respectively. Genetic quality control and linear and logistic regressions were performed. Generalized multifactor dimensional reduction (GMDR) was used to investigate gene-environment interactions. Results: There were 1391 children who passed genetic quality control. Rs2071623 of VIPR2 was associated with axial length (T allele, ß=-0.11 se=0.04 p=0.006), while SNP nominally interacted with outdoor time (T allele, ß=-0.17 se=0.08 p=0.029). Rs2071623 in children with high outdoor exposure had a significant interaction effect on axial length (p=0.0007, ß=-0.19 se=0.056) compared to children with low outdoor exposure. GMDR further suggested the existence of an interaction effect between outdoor time and rs2071623. Conclusions: Rs2071623 within VIPR2 could interact with outdoor time in Han Chinese children. More outdoor exposure could enhance the protective effect of the T allele on axial elongation.

The contribution of inner electron excitation to the electronic stopping power of palladium for protons.

The electronic stopping power of palladium (Pd) for protons is investigated based on time-dependent density functional theory combined with Ehrenfest molecular dynamics simulations. The electronic stopping power of Pd with explicitly considering inner electrons for protons is calculated and the excitation mechanism for the inner electrons of Pd is revealed. The velocity proportionality of the low-energy stopping power of Pd is reproduced. Our study verified that the inner electron excitation contributes significantly to the electronic stopping power of Pd in the high energy range, which is strongly dependent on the impact parameter. The electronic stopping power obtained from the off-channeling geometry is in quantitative agreement with the experimental data in a wide velocity range, and the discrepancy around the stopping maximum is further reduced by considering the relativistic correction on the binding energy of inner electrons. The velocity dependence of the mean steady-state charge of protons is quantified, and the results showed that the participation of 4p-electrons reduces the mean steady-state charge of protons, and consequently decreases the electronic stopping power of Pd in the low energy range.

Effect of low-dose atropine eyedrops on pupil metrics: results after half a year of treatment and cessation.

PURPOSE: To evaluate the effect of low-dose atropine eyedrops on pupil metrics. METHODS: This study was based on a randomized, double-masked, placebo-controlled, and cross-over trial in mainland China. In phase 1, subjects received 0.01% atropine or placebo once nightly. After 1 year, the atropine group switched to placebo (atropine-placebo group), and the placebo group switched to atropine (placebo-atropine group). Ocular parameters were measured at the crossover time point (at the 12th month) and the 18th month. RESULTS: Of 105 subjects who completed the study, 48 and 57 children were allocated into the atropine-placebo and placebo-atropine groups, respectively. After cessation, the photopic pupil diameter (PD) and mesopic PD both decreased (- 0.46 ± 0.47 mm, P < 0.001; - 0.30 ± 0.74 mm, P = 0.008), and the constriction ratio (CR, %) increased (4.39 ± 7.54, P < 0.001) compared with values at the crossover time point of the atropine-placebo group; pupil metrics of the atropine-placebo group had no difference from the values at the crossover time point of the placebo-atropine group. After 6 months of treatment, the photopic PD and the mesopic PD increased (0.54 ± 0.67 mm, P < 0.001; 0.53 ± 0.89 mm, P < 0.001), the CR (%) decreased (- 2.53 ± 8.64, P < 0.001) compared with values at the crossover time point of the placebo-atropine group. There was no significant relationship between pupil metrics and myopia progression during 0.01% atropine treatment. CONCLUSION: Pupil metrics and the CR could return to pre-atropine levels after cessation. Pupil metrics had no significant effect on myopia progression during treatment.

Gene-environment interaction in myopia.

Myopia is a health issue that has attracted global attention due to its high prevalence and vision-threatening complications. It is well known that the onset and progression of myopia are related to both genetic and environmental factors: more than 450 common genetic loci have been found to be associated with myopia, while near work and outdoor time are the main environmental risk factors. As for many complex traits, gene-environment interactions are implicated in myopia development. To date, several genetic loci have been found to interact with near work or educational level. Gene-environment interaction research on myopia could yield models that provide more accurate risk predictions, thus improving targeted treatments and preventive strategies. Additionally, such investigations might have the potential to reveal novel genetic information. In this review, we summarised the findings in this field and proposed some topics for future investigations.

Effect of Atropine 0.01% Eye Drops on the Difference in Refraction and Axial Length between Right and Left Eyes.

INTRODUCTION: This study sought to determine whether the application of 0.01% atropine eye drops could impact the disparity in refraction and axial length (AL) between the right and left eyes in Chinese children. METHODS: The study was designed as a double-blind, placebo-controlled randomized trial. A total of 220 children aged 6-12 years were recruited from the Beijing Tongren Hospital in Beijing, China. Participants were randomized in a 1:1 ratio and were prescribed 0.01% atropine or placebo eye drops to be administered once a night to both eyes for the duration of 1 year. The cycloplegic refraction and AL were recorded including baseline, 6 months, and again at the 12 months. RESULTS: After 1-year follow-up period, 76 (69%) and 83 (75%) subjects of the initial 220 participants were identified as the 0.01% atropine and placebo groups, respectively. The inter-ocular difference in spherical equivalent refraction (SER) and AL demonstrated stable values in the 0.01% atropine treatment group (SER: p = 0.590; AL: p = 0.322) analyzed after 1 year, but found a significant increase (SER: p < 0.001; AL: p = 0.001) in the placebo group. Furthermore, over 1 year, eyes with greater myopia in the atropine group exhibited slower myopia progression (0.45 ± 0.44 D) than the lesser myopic eye (0.56 ± 0.44 D) (p = 0.003). CONCLUSION: This study demonstrated that 0.01% atropine could maintain the inter-ocular SER and AL difference. And 0.01% atropine appeared to be more effective in delaying the progression of myopia in eyes with more myopia than in the less myopic eyes.

The performance of an integrated model including retinal information in predicting childhood hypertension.

BACKGROUND: The objective of this study was to examine the association of an integrated model (composed of retinal arteriolar caliber, height, and sex) with blood pressure (BP) among a group of Chinese children, and assess the predictive value of the integrated model for childhood hypertension. METHODS: This study included 1460 candidates aged 12.634 ± 0.420 years. Height, weight, waist circumference, and BP were obtained and ophthalmological measurements were taken. The computer-imaging program (IVAN, University of Wisconsin, Madison, WI) was used to measure calibers of retinal vessels. Receiver-operating characteristic curve (ROC) analyses were performed to assess the accuracy of the integrated model as a diagnostic test of elevated BP in children. RESULTS: The accuracy of the integrated model (assessed by area under the curve) for identifying elevated BP was 0.777 (95% confidence interval: 0.742-0.812). The optimal threshold of the integrated model for defining hypertension was 0.153, and the calculation formula for the specific predictive risk was: Logit (p/1 - p) = -5.666 - 0.261 × retinal arteriolar caliber + 0.945 × sex + 0.438 × height. In identifying elevated BP, the sensitivity and specificity were 0.711 and 0.736, respectively. CONCLUSIONS: The model containing eye message is a comprehensive and relatively effective index to identify elevated BP in 12-year-old children, which can offer assistance to further understand childhood microcirculation disease. IMPACT: We firstly incorporated retinal vascular diameter, sex, and height into one integrated model to identify hypertension in 12-year-old children. The current discrimination of hypertension in children is difficult. There have been some studies to simplify the diagnosis of children's hypertension, but they were limited to anthropometric measurements. We proposed a composed model containing microcirculation information to predict childhood hypertension. Based on the knowledge that microcirculation is not only a means to study the manifestations but also early pathogenic correlates of hypertension, the combined model containing microcirculation message as a method may provide new insights into the diagnosis of childhood hypertension.

Flap-making patterns and corneal characteristics influence opaque bubble layer occurrence in femtosecond laser-assisted laser in situ keratomileusis.

BACKGROUND: Opaque bubble layer (OBL), which generates from photo-disruptive procedures on the cornea, has been a common phenomenon during femtosecond laser-assisted refractive surgeries and it would potentially impact eye tracking and flap lifting. And we have observed that an updated flap-making pattern could form less OBL clinically than the traditional pattern, which needed further approval. Thus, the purpose of this study is to prove our observation and investigate the possible risk factors related to the occurrence and type of OBL in laser in situ keratomileusis (LASIK) flaps using the Visumax laser system. METHODS: This prospective study included 167 eyes of 86 patients (mean age: 27.5 ± 6.1 years) undergoing bilateral femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia/myopic astigmatism by the same surgeon from April 2020 to August 2020. Preoperative data on refraction, central corneal thickness (CCT), and keratometry as well as intraoperative data were included for analysis. A new flap-making pattern creating an offset between flap-cut and side-cut was adopted to compare with the traditional pattern. The operation video of flap formation was analyzed to identify the existence and type of OBL. The area covered by OBL and the ratio of OBL to flap were calculated using Image J software. RESULTS: Among 167 eyes, 54 eyes (32.3%) developed OBLs, consisting of 31 as hard OBL coexisting with soft OBL, and 23 as soft OBL alone. The OBL incidence was significantly reduced in eyes with the new flap-making pattern compared with the traditional pattern (13.8% vs. 52.5%, P < 0.001). Hard OBLs had larger area ratios than soft OBLs (14.3 ± 8.3% vs. 1.1 ± 1.8%, P < 0.001). Univariate analyses revealed that eyes with more myopia, thicker CCT, and traditional flap-making patterns were more likely to develop OBLs. Multivariate analysis further confirmed that more myopia, thicker CCT, and traditional flap-making pattern were risk factors for OBLs. A Larger corneal diameter was associated with a higher incidence of hard OBL when applying the traditional flap-making process. CONCLUSION: More myopia, thicker CCT, and larger corneal diameter were risk factors for OBL development during flap creation, whereas a flap-making pattern with an offset between flap-cut and side-cut could reduce the incidence of OBL.

A Nanocluster [Ag307Cl62(SPhtBu)110]: Chloride Intercalation, Specific Electronic State, and Superstability.

The controlling synthesis of novel nanoclusters of noble metals (Au, Ag) and the determination of their atomically precise structures provide opportunities for investigating their specific properties and applications. Here we report a novel silver nanocluster [Ag307Cl62(SPhtBu)110] (Ag307) whose structure is determined by X-ray single crystal diffraction. The structure analysis shows that nanocluster Ag307 contains a Ag167 core, a surface shell of [Ag140Cl2S110], and a Cl60 intermediate layer located between Ag167 and [Ag140Cl2S110]. It is a first example that such many chlorides are intercalated into a Ag nanocluster. Chlorides are released in situ from solvent CHCl3. Nanocluster Ag307 exhibits superstability. Differential pulse voltammetry experiment reveals that Ag307 has continuous charging/discharging behavior with a capacitance value of 1.39 aF, while the Ag307 has a surface plasmonic feature. These characteristics show that Ag307 is of metallic behavior. However, its electron paramagnetic resonance (EPR) spectra display a spin magnetic behavior which could be originated from the unpassivated dangling bonds of surface atoms. The direct capture of EPR signals can be attributed to the Cl- intercalating layer which partly suppresses the electronic interactions between core and surface atoms, resulting in the relatively independent electronic states for core and surface atoms.

Effect of reading with a mobile phone and text on accommodation in young adults.

PURPOSE: To investigate the effects of reading with mobile phone versus text on accommodation accuracy and near work-induced transient myopia (NITM) and its subsequent decay during near reading in young adults with mild to moderate myopia. METHODS: The refractions of 31 young adults were measured with an open-field autorefractor (WAM-5500, Grand Seiko) for two reading tasks with a mobile phone and text at 33 cm. The mean age of the young adults was 24.35 ± 1.80 years. The baseline refractive aspects were determined clinically with full distance refractive correction in place. The initial NITM and its decay time and accommodative lag were assessed objectively immediately after binocularly viewing a mobile phone or text for 40 min. RESULTS: The mean ± standard deviation (SD) initial NITM magnitude was greater for reading with text (0.23 ± 0.26 D) than for reading with mobile phone (0.12 ± 0.17 D), but there was no significant difference between the two reading tasks (p = 0.082). The decay time (median, first quartile, and third quartile) was 60 s (16, 154) and 70 s (32, 180) in the phone task and text task groups, respectively. There was also no significant difference in the decay time between the two reading types in general (p = 0.294). The accommodative lags of text tasks and mobile phones tasks were equivalent (1.27 ± 0.52 D vs 1.31 ± 0.64 D, p = 0.792). CONCLUSION: There were no significant differences in accommodative lags and the initial NITM and its decay time between reading with a mobile phone and text in young adults.

Progression of myopia in a natural cohort of Chinese children during COVID-19 pandemic.

PURPOSE: To determine myopia progression in children during the COVID-19 and the related factors associated with myopia. METHODS: All subjects underwent three-timepoint ocular examinations that were measured in July 2019, January, and August 2020. We compared the changes in uncorrected visual acuity (UCVA), mydriatic spherical equivalent (SE), and axial length (AL) between two periods (before and during COVID-19). A questionnaire was performed to investigate risk factors for myopia. RESULTS: Compared with before the COVID-19, the mean (S.D.) myopia progression during the COVID-19 was significantly higher in right eyes (- 0.93 (0.65) vs. - 0.33 (0.47) D; p < 0.001). However, the differences in UCVA changes and the axial elongation between two periods were clinically insignificant. Through logistic regressive analysis, we found the difference of the SE changes was associated with the baseline AL (P = 0.028; 95% confidence interval [CI], 1.058, 2.632), online education (P = 0.02; 95% CI, 1.587, 8.665), and time of digital screen (p < 0.005; 95% CI, 1.587, 4.450). CONCLUSIONS: Children were at higher risk of myopia progression during COVID-19, which was associated with the baseline AL, the longtime online learning, and digital screen reading.

Wavefront excimer laser refractive surgery for adults with refractive errors.

BACKGROUND: Refractive errors (conditions in which the eye fails to focus objects accurately on the retina due to defects in the refractive system), are the most common cause of visual impairment. Myopia, hyperopia, and astigmatism are low-order aberrations, usually corrected with spectacles, contact lenses, or conventional refractive surgery. Higher-order aberrations (HOAs) can be quantified with wavefront aberration instruments and corrected using wavefront-guided or wavefront-optimized laser surgery. Wavefront-guided ablations are based on preoperative measurements of HOAs; wavefront-optimized ablations are designed to minimize induction of new HOAs while preserving naturally occurring aberrations. Two wavefront procedures are expected to produce better visual acuity than conventional procedures. OBJECTIVES: The primary objective was to compare effectiveness and safety of wavefront procedures, laser-assisted in-situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) or laser epithelial keratomileusis (LASEK) versus corresponding conventional procedures, for correcting refractive errors in adults for postoperative uncorrected visual acuity, residual refractive errors, and residual HOAs. The secondary objective was to compare two wavefront procedures. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; 2019, Issue 8); Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Sciences (LILACS); the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 6 August 2019. We imposed no restrictions by language or year of publication. We used the Science Citation Index (September 2013) and searched the reference lists of included trials to identify additional relevant trials. SELECTION CRITERIA: We included randomized controlled trials (RCTs) comparing either wavefront modified with conventional refractive surgery or wavefront-optimized with wavefront-guided refractive surgery in participants aged ⪰ 18 years with refractive errors. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology. MAIN RESULTS: We identified 33 RCTs conducted in Asia, Europe and United States, totaling 1499 participants (2797 eyes). Participants had refractive errors ranging from high myopia to low hyperopia. Studies reported at least one of the following review-specific outcomes based on proportions of eyes: with uncorrected visual acuity (UCVA) of 20/20 or better, without loss of one or more lines of best spectacle-corrected visual acuity (BSCVA), within ± 0.50 diopters (D) of target refraction, with HOAs and adverse events. Study characteristics and risk of bias Participants were mostly women, mean age 29 and 53 years, and without previous refractive surgery, ocular pathology or systemic comorbidity. We could not judge risks of bias for most domains of most studies. Most studies in which both eyes of a participant were analyzed failed to account for correlations between two eyes in the analysis and reporting of outcomes. Findings For the primary comparison between wavefront (PRK or LASIK or LASEK) and corresponding conventional procedures, 12-month outcome data were available from only one study of PRK with 70 participants. No evidence of more favorable outcomes of wavefront PRK on proportion of eyes: with UCVA of 20/20 or better (risk ratio [RR] 1.03, 95% confidence interval (CI) 0.86 to 1.24); without loss of one or more lines of BSCVA (RR 0.94, 95% CI 0.81 to 1.09); within ± 0.5 D of target refraction (RR 1.03, 95% CI 0.86 to 1.24); and mean spherical equivalent (mean difference [MD] 0.04, 95% CI -0.11 to 0.18). The evidence for each effect estimate was of low certainty. No study reported HOAs at 12 months. At six months, the findings of two to eight studies showed that overall effect estimates and estimates by subgroup of PRK or LASIK or LASEK were consistent with those for PRK at 12 month, and suggest no difference in all outcomes. The certainty of evidence for each outcome was low. For the comparison between wavefront-optimized and wavefront-guided procedures at 12 months, the overall effect estimates for proportion of eyes: with UCVA of 20/20 or better (RR 1.00, 95% CI 0.99 to 1.02; 5 studies, 618 participants); without loss of one or more lines of BSCVA (RR 0.99, 95% CI 0.96 to 1.02; I2 = 0%; 5 studies, 622 participants); within ± 0.5 diopters of target refraction (RR 1.02, 95% CI 0.95 to 1.09; I2 = 33%; 4 studies, 480 participants) and mean HOAs (MD 0.03, 95% CI -0.01 to 0.07; I2 = 41%; 5 studies, 622 participants) showed no evidence of a difference between the two groups. Owing to substantial heterogeneity, we did not calculate an overall effect estimate for mean spherical equivalent at 12 months, but point estimates consistently suggested no difference between wavefront-optimized PRK versus wavefront-guided PRK. However, wavefront-optimized LASIK compared with wavefront-guided LASIK may improve mean spherical equivalent (MD -0.14 D, 95% CI -0.19 to -0.09; 4 studies, 472 participants). All effect estimates were of low certainty of evidence. At six months, the results were consistent with those at 12 months based on two to six studies. The findings suggest no difference between two wavefront procedures for any of the outcomes assessed, except for the subgroup of wavefront-optimized LASIK which showed probable improvement in mean spherical equivalent (MD -0.12 D, 95% CI -0.19 to -0.05; I2 = 0%; 3 studies, 280 participants; low certainty of evidence) relative to wavefront-guided LASIK. We found a single study comparing wavefront-guided LASIK versus wavefront-guided PRK at six and 12 months. At both time points, effect estimates consistently supported no difference between two procedures. The certain of evidence was very low for all estimates. Adverse events Significant visual loss or optical side effects that were reported were similar between groups. AUTHORS' CONCLUSIONS: This review suggests that at 12 months and six months postoperatively, there was no important difference between wavefront versus conventional refractive surgery or between wavefront-optimized versus wavefront-guided surgery in the clinical outcomes analyzed. The low certainty of the cumulative evidence reported to date suggests that further randomized comparisons of these surgical approaches would provide more precise estimates of effects but are unlikely to modify our conclusions. Future trials may elect to focus on participant-reported outcomes such as satisfaction with vision before and after surgery and effects of remaining visual aberrations, in addition to contrast sensitivity and clinical outcomes analyzed in this review.

Effect of internal limiting membrane peeling on normal retinal function evaluated by microperimetry-3.

BACKGROUND: To evaluate the effect of internal limiting membrane (ILM) peeling surrounding macular holes (MH) for the function of retina by microperimetry-3(MP-3). METHODS: This is a prospective, cohort study which included patients with MHs who were treated by 23-gauge 3-port pars plana vitrectomy and ILM peeling with air tamponade. Color fundus photography, retinal optical coherence tomography and MP-3 were performed 1 week before, 1 and 4 months after the operation. In MP-3 examination, a customized follow-up pattern with 45 spots in the central 8° visual field was used. The spots corresponding to the retina surrounding macular holes were selected for comparison of pre- and post-operative function. RESULTS: We incuded 44 eyes of 44 patients with best corrected visual acuity (BCVA) of 1.06 ± 0.40 (logMAR). All eyes achieved an anatomical success at 4 months. BCVA significantly improved at 1 month (0.53 ± 0.30, P < 0.01) and 4 months (0.31 ± 0.24, P < 0.01), respectively. Mean retinal sensitivity (MRS, dB) of the retina surrounding macular hole was 23.46 ± 3.01 dB at baseline, and significantly increased at 1 month (26.25 ± 2.31 dB, u = - 4.88, P < 0.01) and 4 months (27.14 ± 2.45 dB, t = - 6.29, P < 0.01). Patients with increased MRS are significantly younger than those with deceased MRS (59.72 ± 3.22 years vs. 65.60 ± 8.19 years, P < 0.01). After ILM peeling, the increasing extent of MRS was significantly higher in inferior and nasal retina than in superior and temporal retina at 1 and 4 months (P < 0.05). CONCLUSION: ILM peeling in normal retina will not decrease the retinal function in a short-term after surgery.

Association between blood pressure and retinal arteriolar and venular diameters in Chinese early adolescent children, and whether the association has gender difference: a cross-sectional study.

BACKGROUND: To establish the independent association between blood pressure (BP) and retinal vascular caliber, especially the retinal venular caliber, in a population of 12-year-old Chinese children. METHODS: We have examined 1501 students in the 7th grade with mean age of 12.7 years. A non-mydriatic fundus camera (Canon CR-2, Tokyo, Japan) was used to capture 450 fundus images of the right eyes. Retinal vascular caliber was measured using a computer-based program (IVAN). BP was measured using an automated sphygmomanometer (HEM-907, Omron, Kyoto, Japan). RESULTS: The mean retinal arteriolar caliber was 145.3 µm (95% confidence interval [CI], 110.6-189.6 µm) and the mean venular caliber was 212.7 µm (95% CI, 170.6-271.3 µm). After controlling for age, sex, axial length, BMI, waist, spherical equivalent, birth weight, gestational age and fellow retinal vessel caliber, children in the highest quartile of BP had significantly narrower retinal arteriolar caliber than those with lower quartiles (P for trend< 0.05). Each 10-mmHg increase in BP was associated with narrowing of the retinal arterioles by 3.00 µm (multivariable-adjusted P < 0.001), and the results were consist in three BP measurements. The association between BP measures and retinal venular caliber did not persist after adjusting for fellow arteriolar caliber. And there was no significant interaction between BP and sex, age, BMI, and birth status. CONCLUSIONS: In a large population of adolescent Chinese children, higher BP was found to be associated with narrower retinal arterioles, but not with retinal venules. Sex and other confounding factors had no effect on the relationship of BP and retinal vessel diameter.

Five-year incidence and progression of myopic maculopathy in a rural Chinese adult population: the Handan Eye Study.

PURPOSE: To determine the cumulative five-year incidence and progression of myopic maculopathy in a rural Chinese adult population. METHODS: The Handan Eye Study was a population-based longitudinal study. In 2006, 6830 subjects aged 30+ years participated in this study (baseline). Five years later, 5394 subjects (follow-up rate: 85.3%) took part in the follow-up study. Participants had a detailed eye examination, including visual acuity, standardized refraction and fundus photography according to a similar protocol at both baseline and follow-up. Myopic maculopathy was defined as any of the following signs: diffuse chorioretinal atrophy, patchy chorioretinal atrophy, macular atrophy, lacquer cracks and myopic choroidal neovascularization at the posterior pole. Parapapillary atrophy was assessed separately. RESULTS: Of 5394 participants, 5078 (10 021 eyes) had gradable fundus photographs. Over the five years, four participants (five eyes) developed new myopic maculopathy, with an eye-specific incidence of 0.05% (95% CI, 0.02-0.10%). Among the 51 eyes with myopic maculopathy at baseline, the progression occurred in 18 eyes (35.3%), with new signs of patchy chorioretinal atrophy in 11 eyes (21.6%), diffuse chorioretinal atrophy in seven eyes (13.7%), lacquer cracks in three eyes (6.9%), macular atrophy in three eyes (6.9%) and myopic choroidal neovascularization in two eyes (3.9%). By multivariable analysis, female gender (OR, 9.14; p = 0.004) and higher educational level (OR, 8.24; p = 0.004) were associated with a higher risk of progression of myopic maculopathy, whereas lower myopia at baseline (OR, 0.79; p < 0.0001) and hypertension (OR, 0.21; p = 0.017) were associated with a reduced risk. CONCLUSIONS: The five-year incidence of myopic maculopathy was 0.05% in rural Chinese adults aged 30+ years. The progression rate in participants with myopic maculopathy was 35.3%, indicating the importance of regular follow-up for these patients.

Five-year refractive changes in a rural Chinese adult population and its related factors: the Handan Eye Study.

IMPORTANCE: Provision of refractive changes is important to predict eye care needs for aging population. BACKGROUND: To provide 5-year refractive changes in a rural Chinese adult population. DESIGN: Population-based longitudinal study. PARTICIPANTS: At baseline, 6830 subjects aged 30+ years took part in the Handan Eye Study. A total of 5394 of the 6323 survivors (85.3%) participated in the 5-year follow-up. METHODS: Ocular examinations including standardized refraction were performed according to the same protocol at both baseline and follow-up. MAIN OUTCOME MEASURES: Change in spherical equivalent (SE; sphere + 1/2 cylinder) and astigmatism. RESULTS: A total of 3970 right eyes were available for refraction analysis. The 5-year change in SE for all subjects was +0.17 diopters (D), and was -0.21D, +0.14D, +0.40D and +0.08D for subjects aged 30-39, 40-49, 50-59, and 60-69 years, respectively. By binary regression analysis, myopic shift was associated with severe nuclear opacity, longer axil length, diabetes and large change of lens power, while hyperopic shift was associated with older age and ocular hypertension at baseline. There was a mean change of 0.18D in the against-the-rule astigmatism. CONCLUSIONS AND RELEVANCE: There was a myopic shift for those 30-39 years old and a hyperopic shift from 40 to 69 years old in a rural Chinese adult population. Those with severe nuclear opacity, longer axil length, diabetes and large change of lens power tended to have a myopic shift, while those being older and having ocular hypertension at baseline were prone to have a hyperopic shift. There was also an increase in against-the-rule astigmatism in this population.

Effect of uncorrection versus full correction on myopia progression in 12-year-old children.

PURPOSE: To investigate the effects of no correction versus full correction on myopia progression in Chinese children over a period of 2 years. METHODS: Myopia was defined as cycloplegic spherical equivalent (SE) of ≤ -0.50 D. Uncorrection was defined as no spectacles worn, and full correction was defined as when the value of SE subtracted from the dioptric power of the child's current spectacles was less than 0.5 D. Ocular examinations included visual acuity, cycloplegic autorefraction, axial length and vertometer measurements. Questionnaires were completed by parents on behalf of the children. RESULTS: A total of 121 myopic children, with a median age of 12.7 years, were screened from the Anyang Childhood Eye Study, with 65 in the uncorrected group and 56 in the full correction group. At 2-year follow-up, children with no correction had slower myopia progression (-0.75 ± 0.49 D vs. -1.04 ± 0.49 D, P < 0.01) and less axial elongation (0.45 ± 0.18 mm vs. 0.53 ± 0.17 mm, P = 0.02) than children with full correction. In multivariate modeling, adjusting for baseline SE or axial length, age, gender, height, number of myopic parents, age at myopia onset, and time spent in near work and outdoors, children with no correction still had slower myopia progression (-0.76 ± 0.07 vs. -1.03 ± 0.08 D, P < 0.01) and less axial elongation (0.47 ± 0.03 mm vs. 0.51 ± 0.03 mm, P < 0.01). Myopia progression decreased significantly with an increasing amount of undercorrection in all children (r = 0.22, b = 0.16, P = 0.01). CONCLUSION: Our findings suggest that myopic defocus slows the progression of myopia in already myopic children, supporting previous findings from animal studies.

Studies using concentric ring bifocal and peripheral add multifocal contact lenses to slow myopia progression in school-aged children: a meta-analysis.

PURPOSE: To evaluate the effect of soft contact lens with concentric ring bifocal and peripheral add multifocal designs on controlling myopia progression in school-aged children. METHODS: We systematically searched MEDLINE, EMBASE, Cochrane Library and reference lists of included trials. Methodological quality of included trials was assessed using Jadad Scale and Newcastle-Ottawa Quality Assessment Scale items. RESULTS: We identified five randomised controlled trials (RCTs) and three cohort studies with a total of 587 myopic children. Compared with the control group, concentric ring bifocal soft contact lenses showed less myopia progression with a weighted mean difference (WMD) of 0.31 D (95% CI, 0.05~0.57 D, p = 0.02) and less axial elongation with a WMD of -0.12 mm (95% CI, approximately -0.18 to -0.07 mm, p < 0.0001) at 12 months. Relative to the control group, peripheral add multifocal soft contact lenses showed less myopia progression with a WMD of 0.22 D (95% CI 0.14~0.31 D, p < 0.0001) and less axial elongation of -0.10 mm (95% CI -0.13~0.07 mm, p < 0.0001) at 12 months, respectively. The soft contact lenses with concentric ring bifocal and peripheral add multifocal designs produced additional myopia control rates of 30~38% for slowing myopia progression and 31~51% for lessening axial elongation within 24 months. CONCLUSIONS: Both concentric ring bifocal and peripheral add multifocal soft contact lenses are clinically effective for controlling myopia in school-aged children, with an overall myopia control rates of 30~50% over 2 years. Concentric ring bifocal soft contact lenses seem to have greater effect than peripheral add multifocal soft contact lenses.

Laser-assisted subepithelial keratectomy (LASEK) versus photorefractive keratectomy (PRK) for correction of myopia.

BACKGROUND: Myopia (near-sightedness or short-sightedness) is a condition in which the refractive power of the eye is greater than required. The most frequent complaint of people with myopia is blurred distance vision, which can be eliminated by conventional optical aids such as spectacles or contact lenses, or by refractive surgery procedures such as photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK). PRK uses laser to remove the corneal stroma. Similar to PRK, LASEK first creates an epithelial flap and then replaces it after ablating the corneal stroma. The relative benefits and harms of LASEK and PRK, as shown in different trials, warrant a systematic review. OBJECTIVES: The objective of this review is to compare LASEK versus PRK for correction of myopia by evaluating their efficacy and safety in terms of postoperative uncorrected visual acuity, residual refractive error, and associated complications. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision group Trials Register) (2015 Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to December 2015), EMBASE (January 1980 to December 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to December 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 December 2015. We used the Science Citation Index and searched the reference lists of the included trials to identify relevant trials for this review. SELECTION CRITERIA: We included in this review randomized controlled trials (RCTs) comparing LASEK versus PRK for correction of myopia. Trial participants were 18 years of age or older and had no co-existing ocular or systemic diseases that might affect refractive status or wound healing. DATA COLLECTION AND ANALYSIS: Two review authors independently screened all reports and assessed the risk of bias of trials included in this review. We extracted data and summarized findings using risk ratios and mean differences. We used a random-effects model when we identified at least three trials, and we used a fixed-effect model when we found fewer than three trials. MAIN RESULTS: We included 11 RCTs with a total of 428 participants 18 years of age or older with low to moderate myopia. These trials were conducted in the Czech Republic, Brazil, Italy, Iran, China, Korea, Mexico, Turkey, USA, and UK. Investigators of 10 out of 11 trials randomly assigned one eye of each participant to be treated with LASEK and the other with PRK, but did not perform paired-eye (matched) analysis. Because of differences in outcome measures and follow-up times among the included trials, few trials contributed data for many of the outcomes we analyzed for this review. Overall, we judged RCTs to be at unclear risk of bias due to poor reporting; however, because of imprecision, inconsistency, and potential reporting bias, we graded the quality of the evidence from very low to moderate for outcomes assessed in this review.The proportion of eyes with uncorrected visual acuity of 20/20 or better at 12-month follow-up was comparable in LASEK and PRK groups (risk ratio (RR) 0.98, 95% confidence interval (95% CI) 0.92 to 1.05). Although the 95% CI suggests little to no difference in effect between groups, we judged the quality of the evidence to be low because only one trial reported this outcome (102 eyes). At 12 months post treatment, data from two trials suggest no difference or a possibly small effect in favor of PRK over LASEK for the proportion of eyes achieving ± 0.50 D of target refraction (RR 0.93, 95% CI 00.84 to 1.03; 152 eyes; low-quality evidence). At 12 months post treatment, one trial reported that one of 51 eyes in the LASEK group lost one line or more best-spectacle corrected visual acuity compared with none of 51 eyes in the PRK group (RR 3.00, 95% CI 0.13 to 71.96; very low-quality evidence).Three trials reported adverse outcomes at 12 months of follow-up or longer. At 12 months post treatment, three trials reported corneal haze score; however, data were insufficient and were inconsistent among the trials, precluding meta-analysis. One trial reported little or no difference in corneal haze scores between groups; another trial reported that corneal haze scores were lower in the LASEK group than in the PRK group; and one trial did not report analyzable data to estimate a treatment effect. At 24 months post treatment, one trial reported a lower, but clinically unimportant, difference in corneal haze score for LASEK compared with PRK (MD -0.22, 95% CI -0.30 to -0.14; 184 eyes; low-quality evidence). AUTHORS' CONCLUSIONS: Uncertainty surrounds differences in efficacy, accuracy, safety, and adverse effects between LASEK and PRK for eyes with low to moderate myopia. Future trials comparing LASEK versus PRK should follow reporting standards and follow correct analysis. Trial investigators should expand enrollment criteria to include participants with high myopia and should evaluate visual acuity, refraction, epithelial healing time, pain scores, and adverse events.

Peripapillary retinal nerve fibre layer thickness and its association with refractive error in Chinese children: the Anyang Childhood Eye Study.

BACKGROUND: To report the thickness of the peripapillary retinal nerve fibre layer (pRNFL) in Chinese children and examine its association with refractive error, axial length (AL) and optic disc parameters. DESIGN: Population-based cross-sectional study. PARTICIPANTS: A total of 2893 seven-year-old children from 11 randomly selected primary schools in Anyang, central China. METHODS: Participants underwent ophthalmic examinations including optical biometry, cycloplegic autorefraction and spectral-domain ocular coherence tomography. MAIN OUTCOME MEASURES: Retinal nerve fibre layer thickness in 16 radial sections, cycloplegic spherical equivalent, AL. RESULTS: The mean (SD) average RNFL thickness was 102.01(8.02) µm. The average RNFL thickness decreased with smaller disc area (r = 0.18, R2 = 0.03, P < 0.0001), bigger cup area (r = -0.11, R2 = 0.01, P < 0.0001), smaller rim area (r = 0.28, R2 = 0.08, P < 0.0001), smaller nerve head volume (r = 0.27, R2 = 0.07, P < 0.0001), longer AL (r = -0.15, R2 = 0.02, P < 0.0001) and a negative spherical equivalent (r = 0.11, R2 = 0.01, P < 0.0001). Hyperopic children had a thicker RNFL than emmetropic children [102.45(8.13) µm vs. 100.81 (7.18) µm, P < 0.001]. Myopic children had thinner RNFL than emmetropic children [99.17 (7.69) µm vs. 100.81 (7.18) µm, P < 0.05]. CONCLUSION: Retinal nerve fibre layer thickness decreased with increasing AL, higher myopia, bigger cup area, smaller disc and rim area, and a smaller nerve head volume, but the coefficient of determination for all these associations was small. The RNFL in myopes was significantly thinner than emmetropes or hyperopes, but with small absolute differences. The study provides RNFL values for healthy 7-year-old Chinese children. Follow up of this cohort to observe the change of RNFL thickness with myopia and possible change in detected associations with age is planned.