Investigation of Choroidal Blood Flow and Thickness Changes Induced by Near Work in Young Adults.

PURPOSE: This research aimed to determine the effects of near work on macular choroidal blood flow and thickness in young adults. METHODS: A total of 109 participants (19-28 years old) were recruited from Capital Medical University in China. The participants spent 40 min reading a book text at a distance of 33 cm. Swept-source optical coherence tomography/optical coherence tomography angiography (SS-OCT/OCTA) was performed to measure the changes in choriocapillaris perfusion area (CCPA) and choroidal thickness (ChT) after 40 min of near work. The SS-OCT/OCTA data covered an area of 6 mm × 6 mm, which centered on the fovea. RESULTS: The baseline ChT and CCPA before near work were negatively correlated with AL, while positively correlated with the magnitude of spherical equivalent (p < .001). Total CCPA decreased significantly by 6 mm × 6 mm macular area after near work compared to that before near work (24.26 ± 1.96 vs. 24.63 ± 1.61 mm2, p<.001). The macular ChT was lower after 40 min of reading than that before 40 min of reading, but no significant difference was observed (302.25 ± 77.69 vs. 304.92 ± 79.73 µm, p = .078). The extent of choroidal thinning was significantly positively correlated with the magnitude of CCPA reduction (p < .001). The decline in CCPA after near work was significantly positively correlated with axial length (AL; p < .001). CONCLUSION: This study demonstrated that near work significantly decreased CCPA. The extent of CCPA reduction after near work was associated with higher severity of myopia and choroidal thinning. The baseline CCPA and ChT decreased gradually with AL.

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 effect of atropine 0.01% eyedrops on relative peripheral refraction in myopic children.

BACKGROUND: Relative peripheral refraction (RPR) is a significant factor that participates in myopic development. Here, we evaluated the effects of atropine 0.01% eyedrops, as an antimyopia drug, on RPR. METHODS: Seventy-three children were enrolled from a randomized, double-blinded, placebo-0.01% atropine eyedrops cross-over trial. The study group had used the placebo for one year and then crossed over to atropine 0.01% eyedrops for half a year. The control group had used 0.01% atropine for one year and then crossed over to placebo eyedrops for half a year. Central and horizontal peripheral refractions (15° and 30° at the temporal and nasal retina) were measured under non-cycloplegia and cycloplegia. RESULTS: No significant differences in age, gender, and central refraction were identified between the two groups (P > 0.05). Under non-cycloplegia, the control group showed significant relative hyperopia in the temporal 30° retina and the nasal retina (P = 0.031; P < 0.001; P < 0.001). In the study group, the relative hyperopia in the temporal 30° retina disappeared (P = 0.983). After cycloplegia, the control group had less myopia in central refractions and less hyperopia in temporal RPR (P < 0.001; P = 0.039; P < 0.001). The study group did not present significant changes in central refractions and temporal RPR (P = 0.122; P = 0.222; P = 0.475). CONCLUSIONS: For myopic children, atropine 0.01% eyedrops can alleviate relative hyperopia in the temporal retina and the hyperopic shift before cycloplegia. The effect might participate in myopia control.

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.

Myopia progression after cessation of low-dose atropine eyedrops treatment: A two-year randomized, double-masked, placebo-controlled, cross-over trial.

PURPOSE: The purpose of the study was to evaluate myopia progression and axial elongation after stopping 0.01% atropine eye drops through a 2-year cross-over study. METHODS: This study was a randomized, double-masked, placebo-controlled, cross-over trial in mainland China. 220 children aged 6-12 years with spherical equivalent range of -1.00 D to -6.00 D in both eyes were enrolled in Phase 1 for 1 year. Children who had completed the first year's follow-up continued in the second phase. In Phase 2, the placebo group was crossed over to the 0.01% atropine group (referred to as the 'placebo-atropine group'), and the 0.01% atropine group was crossed over to the placebo group (referred to as the 'atropine-placebo group'). All children underwent the examination of cycloplegic refraction and axial length at a 6-month interval. Only data from right eyes were included in analysis. RESULTS: One hundred thirty-three subjects completed 2 years of follow-up. In the first year, the mean myopia progression in atropine-placebo group was 0.21 ± 0.08 D slower than that in placebo-atropine group. After cross-over treatment, the mean myopia progression in atropine-placebo group was 0.22 ± 0.07D faster than that in placebo-atropine group in the second year. Over 2 years, the mean myopia progression was -1.26 ± 0.66D and -1.25 ± 0.70D in the atropine-placebo and placebo-atropine groups (p = 0.954). CONCLUSIONS: The difference in myopia progression between atropine-placebo group and placebo-atropine group in Phase 1 was similar to Phase 2 during the cross-over treatment. Through our cross-over trial, the results suggest that there is no rebound effect after using 0.01% atropine eye drops to prevent progression of myopia.

Effect of 0.01% atropine eyedrops on intraocular pressure in schoolchildren: a randomized clinical trial.

AIM: To assess the effect of 0.01% atropine eye drops on intraocular pressure (IOP) in myopic children. METHODS: A placebo-controlled, double-masked, randomized study. Totally 220 children aged 6 to 12y with myopia ranging from -1.00 to -6.00 D in both eyes were enrolled. Children were randomized in a 1:1 ratio to either 0.01% atropine eye drops or a placebo group using generated random numbers. All participants underwent the examination of IOP and cycloplegic refraction at baseline, 6 and 12mo. The change of IOP and the proportion of subjects with increased IOP in atropine and placebo groups were compared. RESULTS: Of 220 children, 117 were boys (53.2%). A total of 159 (72.3%) participants completed the follow-up at the 1-year study. At baseline, the mean IOP was 15.74 mm Hg (95%CI, 15.13 to 16.34 mm Hg) for the 0.01% atropine group and 15.59 mm Hg (95%CI, 15.00 to 16.19 mm Hg) for placebo group (mean difference, 0.14 mm Hg; P=0.743) after adjusting for central corneal thickness at baseline. At one year follow-up, the mean change of IOP was 0.16 mm Hg (95%CI, -0.43 to 0.76 mm Hg) for the 0.01% atropine group and -0.11 mm Hg (95%CI, -0.71 to 0.50 mm Hg) for placebo group (mean difference, 0.27 mm Hg; P=0.525) after adjusting for central corneal thickness. The 51.4% of children have increased IOP in the 0.01% atropine group, compared with 45.9% in the placebo group (P=0.511). CONCLUSION: The 0.01% atropine eye drops do not significantly affect the risk of elevated IOP. It is relatively safer to use in the studies that try to minimize myopia progression. However, a further long-duration study is required to be validated.

New loci for refractive errors and ocular biometric parameters in young Chinese Han adults.

Myopia has become a major public health issue with an increasing prevalence. There are still individuals who experience similar environmental risk factors and, yet, remain non-myopic. Thus, there might be genetic factors protecting people from myopia. Considering the opposite ocular characteristics of primary angle closure glaucoma (PACG) to myopia and possible common pathway between them, we propose that certain risk genes for PACG might act as a protective factor for myopia. In this study, 2,678 young adults were genotyped for 37 targeted single nucleotide polymorphisms. Compared with emmetropia, rs1401999 (allele C: OR=0.795, P=0.03; genotype in dominant model: OR=0.759, P=0.02) and rs1258267 (allele A: OR=0.824, P=0.03; genotype in dominant model: OR=0.603, P=0.01) were associated with low to moderate myopia and high myopia, respectively. Genotype under recessive model of rs11024102 was correlated with myopia (OR=1.456, P=0.01), low to moderate myopia (OR=1.443, P=0.02) and high myopia (OR=1.453, P=0.02). However, these associations did not survive Bonferroni correction. Moreover, rs1401999, rs1258267, and rs11024102 showed associations with certain ocular biometric parameters in different groups. Our study suggests that ABCC5, CHAT and PLEKHA7 might be associated with refractive errors by contributing to the regulation of ocular biometry, in terms of uncorrected results and their biological functions.

Distribution of IOP and its relationship with refractive error and other factors: the Anyang University Students Eye Study.

AIM: To investigate the distribution of intraocular pressure (IOP) and its relationship with refractive error and other factors in university students from Anyang, China. METHODS: A university-based study was conducted. Subjects were invited to complete ophthalmic examinations, including visual acuity, noncontact tonometry (NCT), cycloplegic autorefraction, and ocular biometry. Univariable and multivariable analyses were used to evaluate the associations between IOP and other factors. Only data from right eyes were used in analysis. RESULTS: A total of 7720 subjects aged 16 to 26 years old were included, and 2834 (36.4%) of the participants were male. The mean IOP of the right eye for all subjects was 15.52±3.20 mm Hg (95%CI: 15.45, 15.59). Using multivariate linear regression analysis, IOP was found to correlate significantly with younger age (P<0.001; standardized regression coefficient ß, -0.061; regression coefficient ß, -0.139; 95%CI: -0.18, -0.09), higher myopic refractive error (P=0.044; standardized ß, -0.060; regression coefficient ß, -0.770; 95%CI: -0.15, -0.002), higher central corneal thickness (P<0.001; standardized ß, 0.450; regression coefficient ß, 0.044; 95%CI: 0.04, 0.05), and shorter axial length (AL; P<0.001; standardized ß, -0.061; regression coefficient ß, -0.163; 95%CI: -0.25, -0.07). CONCLUSION: This study described the normal distribution of IOP. In Chinese university students aged 16-26y, higher IOP is associated with younger age, higher myopic refractive error, higher thickness of the central cornea, and shorter AL.

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.

Distribution of ocular biometry in young Chinese eyes: The Anyang University Students Eye Study.

PURPOSE: To investigate the distribution of ocular biometric parameters and its association to refraction in university students in central China. METHODS: Ocular biometric parameters including axial length (AL), central corneal thickness (CCT), keratometry power (K), anterior chamber depth (AQD) and lens thickness (LT) were measured by an optical biometry in a cohort of university students. Corneal radius of curvature (CR), lens position (LP), lens power (PBennett ), vitreous chamber depth (VCD) and AL to corneal radius ratio (AL/CR) were calculated. Cycloplegic refraction was measured using an autorefractor. RESULTS: A total of 7650 undergraduate students participated in this study, with a mean age of 20.0 ± 1.4 years. The following ocular biometric parameters were measured: AL (24.78 ± 1.21 mm), CCT (539.83 ± 33.03 µm), AQD (3.23 ± 0.25 mm), LT (3.47 ± 0.18 mm), CR (7.79 ± 0.27 mm), LP (4.97 ± 0.23 mm), VCD (17.55 ± 1.15 mm), PBennett (25.00 ± 1.07 dioptres) and AL/CR (3.18 ± 0.15). Male subjects were found to have longer AL, thicker CCT, flatter CR, thinner lens, deeper AQD and VCD than female ones. Myopic subjects were found to have longer AL, thinner CCT, steeper CR, thinner and posterior lens, deeper AQD and VCD, lower PBennett and larger AL/CR than emmetropes and hyperopes. Spherical equivalent (SE) showed a negative correlation with AL/CR (r = -0.914), AL (r = -0.755) and VCD (r = -0.751). CONCLUSIONS: This study provided a range of reference values for the main ocular biometric parameters in young adults and reported their distributions based on gender and refractive status. Our study indicates that SE has a strong correlation with AL/CR ratio, AL and VCD.

Effect of body stature on refraction and ocular biometry in Chinese young adults: The Anyang University Students Eye Study.

CLINICAL RELEVANCE: Large-scale data on the association between body stature with biometry parameters and refraction in young adults facilitates an understanding of myopia development. Taller persons have eyes with more negative refractions, longer axial lengths, deeper anterior chambers, flatter corneas, and higher axial length-corneal radius ratio. BACKGROUND: To determine the relationship between body stature with ocular biometry and refraction in young adults. METHODS: This was a cross-sectional university-based study of 16- to 26-year-old students in China. Cycloplegic refraction and corneal curvature were measured using an autorefractor. Ocular parameters, including axial length, anterior chamber depth and lens thickness, were measured using a Lenstar LS900. Data on height and weight were acquired from an annual standardised physical examination and body mass index was calculated. RESULTS: Of 7,971 participants examined in the school clinics, 5,657 (71.0 per cent) were available in the analysis. After adjusting for age, gender, parental myopia, time outdoors, near work and weight, each centimetre of height increase was associated with more negative refraction of -0.023-D, a 0.032-mm increase in axial length, a 0.003-mm increase in anterior chamber depth, a 0.008-mm increase in corneal curvature, and a 0.001 increase in axial length-corneal radius ratio. With regard to weight, a 1-kg heavier person was more likely to have less negative refraction of 0.011-D, a 0.001-mm increase in anterior chamber depth and a 0.002-mm increase in corneal curvature. A similar pattern of significant associations was also found in body mass index. CONCLUSION: Taller, young adults tended to have longer eyes, deeper anterior chambers, flatter corneas, higher axial length-corneal radius ratio, and more negative refraction, adjusted for potential confounders. In contrast, heavier and higher body mass index persons are more hyperopic. The differences in stature may partially explain the variation in refraction and ocular biometric parameters.

Safety and Efficacy of Low-Dose Atropine Eyedrops for the Treatment of Myopia Progression in Chinese Children: A Randomized Clinical Trial.

Importance: Because studies have suggested that atropine might slow the progression of myopia in children, randomized clinical trials are warranted to understand this potential causal relationship. Objective: To evaluate the efficacy and safety of atropine, 0.01%, eyedrops on slowing myopia progression and axial elongation in Chinese children. Design, Setting, and Participants: This was a randomized, placebo-controlled, double-masked study. A total of 220 children aged 6 to 12 years with myopia of -1.00 D to -6.00 D in both eyes were enrolled between April 2018 and July 2018 at Beijing Tongren Hospital, Beijing, China. Cycloplegic refraction and axial length were measured at baseline, 6 months, and 12 months. Adverse events were also recorded. Interventions: Patients were randomly assigned in a 1:1 ratio to atropine, 0.01%, or placebo groups to be administered once nightly to both eyes for 1 year. Main Outcomes and Measures: Mean changes and percentage differences in myopia progression and axial elongation between atropine, 0.01%, or placebo groups. Results: Of 220 participants, 103 were girls (46.8%), and the mean (SD) age was 9.64 (1.68) years. The mean (SD) baseline refractive error and axial length were -2.58 (1.39) D and 24.59 (0.87) mm. Follow-up at 1 year included 76 children (69%) and 83 children (75%) allocated into the atropine, 0.01%, and placebo groups, respectively, when mean myopia progression was -0.49 (0.42) D and -0.76 (0.50) D in the atropine, 0.01%, and placebo groups (mean difference, 0.26 D; 95% CI, 0.12-0.41 D; P < .001), with a relative reduction of 34.2% in myopia progression. The mean (SD) axial elongation in the atropine, 0.01%, group was 0.32 (0.19) mm compared with 0.41 (0.19) mm in the placebo group (mean difference, 0.09 mm; 95% CI, 0.03-0.15 mm; P = .004), with relative reduction of 22.0% in axial elongation. Fifty-one percent and 13.2% of children progressed by at least 0.50 D and 1.00 D in the atropine, 0.01%, group, compared with 69.9% and 34.9% in the placebo group. No serious adverse events related to atropine were reported. Conclusions and Relevance: While the clinical relevance of the results cannot be determined from this trial, these 1-year results, limited by approximately 70% follow-up, suggest that atropine, 0.01%, eyedrops can slow myopia progression and axial elongation in children and warrant future studies to determine longer-term results and potential effects on slowing sight-threatening pathologic changes later in life. Trial Registration: http://www.chictr.org.cn Identifier: ChiCTR-IOR-17013898.

Visual Impairment and Spectacle Use in University Students in Central China: The Anyang University Students Eye Study.

PURPOSE: To investigate the prevalence and associations of visual impairment and spectacle use in university students in central China. DESIGN: Cross-sectional study. METHODS: This study included students aged 16-26 years in China. Study subjects from 2 universities underwent distance visual acuity (VA) assessment in both eyes with a logarithm of the minimum angle of resolution chart and their refractions were measured by cycloplegic autorefraction. Blindness was defined as presenting VA less than three-sixtieth in the better eye (World Health Organization definition), and visual impairment was defined as presenting VA less than six-twelfths. RESULTS: Overall, 9710 undergraduates were enumerated, 7704 (79.3%) subjects were included in this study. The prevalence of uncorrected VA less than six-twelfths and less than three-sixtieth in the better eye were 69.9% and 0.9%, respectively. Only 77.0% (4148/5388) of subjects with uncorrected VA in the better eye of less than six-twelfths wore glasses. For presenting VA, the prevalence of mild (VA <6/12 to 6/18), moderate (VA <6/18 to 6/60), and severe (VA <6/60 to 3/60) visual impairment was 6.3%, 11.2%, and 0.7%, respectively. Overall, 71.7% (4300/6001) of students with myopia (spherical equivalent ≤-0.5 diopters) wore spectacles. In multiple logistic regression analysis, visual impairment was associated with female sex (P < .001) and lower year level of education (P = .006) when presenting with VA. CONCLUSIONS: This study has documented a relatively high prevalence of visual impairment and relatively low spectacle coverage in Chinese university students. Given the potential impact of visual impairment, target education and accessible refraction services are highly important to solve the problem.