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 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.

Cycloplegic refraction by 1% cyclopentolate in young adults: is it the gold standard? The Anyang University Students Eye Study (AUSES).

AIMS: To document the difference between non-cycloplegic and cycloplegic refraction and explore its associated factors in Chinese young adults. METHODS: A school-based study including 7971 undergraduates was conducted in Anyang, Henan Province, China. Cycloplegia was achieved with two drops of 1% cyclopentolate and 1 drop of Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) with a 5 min interval. Non-cycloplegic and cycloplegic refractions were measured by an autorefractor. A paired-sample t-test and Spearman correlation analysis were used for analysis with data from only the right eyes included.  RESULTS: Of the 7971 students examined, 7793 (97.8%) with complete data were included, aging 20.2±1.5 years. Male students accounted for 36.8%. Overall, there was a significant difference between non-cycloplegic and cycloplegic SE (spherical equivalent) of 0.83±0.81D (p<0.01). The difference was 1.80±1.11D, 1.26±0.93D and 0.69±0.69D for those with cycloplegic hyperopia, emmetropia and myopia, respectively (p<0.01 for all). Those with a hyperopic shift less than 0.25D and 0.5D accounted for 11.1% and 34.1%, respectively. A significant relationship was found between difference in SE and cycloplegic refraction (r=0.33, b=0.11, p<0.01). Without cycloplegia, prevalence of hyperopia and emmetropia would be underestimated by 6.2% (1.0% vs 7.2%) and 5.7% (3.8% vs 9.5%), respectively, with prevalence of myopia and high myopia overestimated by 12.1% (95.3% vs 83.2%) and 6.1% (17.2% vs 11.1%).  CONCLUSION: Lack of cycloplegia will lead to significant misclassification of myopia, emmetropia and hyperopia in Chinese young adults. Cycloplegia is therefore essential for this age-group in epidemiological studies.

Relationships between pharmacokinetics and efficacy of Xie-xin decoction in rats with experimental ulcerative colitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Xie-xin decoction (XXD) has been used as a classic formula in China for the treatment of gastrointestinal dysfunction such as ulcerative colitis (UC). However, no potential action mechanisms and active compounds had been systematically investigated. AIM OF THE STUDY: To explore the effectiveness and the material basis of XXD in trinitrobenzene sulfonic acid (TNBS)-induced UC rats. MATERIALS AND METHODS: XXD was administered orally for 8 days at a dosage of 2 or 4g/kg/day. Plasma pharmacokinetic properties and colon tissue concentrations of multiple compounds from XXD were detected. Tissue damage scores, production of interleukin (IL)-10 and myeloperoxidase (MPO), expression of tumor necrosis factor-alpha (TNF-α) and nuclear factor-kappa Bp65 (NF-κBp65) in colon tissues were examined. Canonical correlation analysis was performed to evaluate the relationships between pharmacokinetics and efficacy to elucidate significantly active compounds of XXD. RESULTS: XXD promoted the recovery of colitis and inhibited the colonic inflammation damage in UC rats by reducing the level of MPO and the expression of TNF-α and NF-κBp65, and increasing the production of IL-10 in colon tissues. Efficacy of XXD was positively related with AUC of five plasma compounds (baicalin, berberine, wogonoside, wogonin, and rhein) and concentrations of six colon tissue compounds (coptisine, jatrorrhizine, palmatine, berberine, baicalein and emodin), respectively. CONCLUSIONS: The multiple compounds in plasma and colon tissues from XXD might be the main material basis for therapeutic potentials in UC rats.

Full correction and Undercorrection of Myopia Evaluation Trial: design and baseline data of a randomized, controlled, double-blind trial.

BACKGROUND: To determine the difference in the rate of myopic progression between children wearing single vision lenses with undercorrection of +0.50 D and children whose myopia is fully corrected, and to explore the factors that may influence the process. DESIGN: Randomized, controlled, double-blind trial. PARTICIPANTS: Two hundred children aged 7-15 years with low-to-moderate myopia (-1.5 D to -6.0 D), astigmatism <-1.5 D and anisometropia <1.0 D. METHODS: The children were randomly allocated to wear single vision lenses with full correction or undercorrection by +0.50 D. Ocular examinations and questionnaire surveys for myopia-related factors will be performed every 6 months. MAIN OUTCOME MEASURES: Cycloplegic autorefraction and axial length. RESULTS: Of 200 children, 100 (50%) were girls, 41 (21%) esophoric and 82 (42%) exophoric at near. The characteristics of gender, age, age of myopia onset, phoria, eye dominance, parental myopia, refractive error, axial length, corneal curvature, mean time spent in near work and outdoor activities between the two groups were not significantly different. The accommodative responses at 33 cm, the accommodative demands and lags at infinity were significantly different in the two groups as they were measured with full correction in one group and undercorrection in the other. CONCLUSION: Full correction and Undercorrection of Myopia Evaluation Trial is a clinical trial designed to determine the effectiveness of undercorrection of myopia by +0.5 D on myopic progression in a population of school-aged children known to be susceptible to myopia and to identify the factors influencing the process.