Intraocular pressure and associations in children. The Gobi Desert Children Eye Study

The Effect of Childhood Obesity on Intraocular Pressure, Corneal Biomechanics, Retinal Nerve Fiber Layer, and Central Macular Thickness

PRCIS

Elevated corneal hysteresis (CH) and resistance factor (CRF) in obese and overweight children imply weight's effect on corneal biomechanics. Increased Goldmann-correlated intraocular pressure (IOPg) in obese children indicates glaucoma risk, emphasizing screening for IOP and retinal changes.

PURPOSE

To evaluate the effect of obesity on corneal biomechanics, retinal nerve fiber layer (RNFL), and central macular thickness (CMT) in children.

PATIENTS AND METHODS

In this prospective, cross-sectional, comparative study, 146 eyes of normal-weight, over-weight, and obese children aged between 6 to 17 years were evaluated. The IOPg, corneal compensated IOP (IOPcc), CH, CRF, and the average retinal nerve fiber layer (RNFL), average cup-to-disk ratio (c/d), and central macular thickness (CMT) were measured by Ocular Response Analyser and Spectral-Domain Optical Coherence Tomography (SD-OCT), respectively.

RESULTS

There was no statistically significant difference regarding age, gender, IOPcc, average RNFL thickness, c/d ratio, and CMT among the groups ( P ≥0.05). The IOPg was significantly higher in obese children compared with normal-weight children, while CH and CRF values were significantly higher in both obese and over-weight children compared with healthy ones ( P <0.05). There was a positive correlation between BMI percentile and IOPg, CH, and CRF values.

CONCLUSION

In our study, higher IOPg, corneal hysteresis, and corneal resistance factor values suggest that obese children could be potential candidates for glaucoma. Therefore, it would be appropriate to screen them for IOP and retinal alterations. Further investigations with larger sample size and longer follow-up are needed to understand the risk of glaucoma in obese children.

Problems in CSF and Ophthalmic Disease Research

There has been significant interest and progress in the understanding of cerebrospinal fluid pressure and its relationship to glaucoma and other ophthalmic diseases. However, just as every physiologic fluid pressure fluctuates, cerebrospinal fluid pressure (CSFP) is similarly dynamic. Coupling this with the difficulty in measuring the pressure, there are many obstacles in furthering this field of study. This review highlights some of the difficulties in CSFP research, including fluid compartmentalization, estimation equations, and pressure fluctuation. Keeping these limitations in mind will hopefully improve the quality and context of this burgeoning field.

Visual outcomes of open globe injury patients with traumatic cataracts

PURPOSE

Open globe injury (OGI) is a serious form of ocular trauma that can significantly lower quality of life post-injury due to comorbidities. This study was designed to investigate how traumatic cataracts and other pre-operative variables affect visual outcomes of OGIs.

METHODS

A retrospective review was conducted for OGI patient records with presence of traumatic cataracts, visual outcomes, comorbidity data and provider training. Multivariable logistic regression analysis determined if several pre-operative variables including traumatic cataracts, retinal detachment and hyphema were predictive of final visual acuity and need for retinal surgery. Ancillary multivariable analysis was conducted to evaluate if timing of traumatic cataract extraction predicted poor final visual acuity.

RESULTS

Multivariable logistic regression analysis did not find traumatic cataract to be an independent predictor of final visual outcome in the open globe injury sample population (n = 102, p = 0.386), but did find retinal detachment (p = 0.008), hyphema (p = 0.035) and scleral laceration (p = 0.009) to be independent predictors of poor final visual acuity. In the subgroup of eyes with traumatic cataract (n = 64), delayed cataract extraction was not found to be an independent predictor of poor final visual acuity (p = 0.156).

CONCLUSION

Our results suggest that retinal detachment, hyphema, and scleral laceration influence final visual outcome while traumatic cataract does not. Within the subpopulation of patients that received lens extraction, timing of extraction was not found to independently influence final visual acuity.

Intraocular Pressure, Age, and Central Corneal Thickness in a Healthy Chinese Children Population: The Handan Offspring Myopia Study

PURPOSE

To assess the distribution and factors related to intraocular pressure (IOP) in a Chinese children population in Northern China.

METHODS

1,238 offspring aged 6 to 18 years, residing in six villages, were recruited for this current study, the Handan Offspring Myopia Study. Participants underwent an interviewer-administered questionnaire and a complete ocular examination, including standardized measurement of IOP with Perkins applanation tonometry.

RESULTS

1,648 eyes of 828 children were included in the analysis. The mean IOP was 13.9 ± 1.6 mmHg. The mean IOP for the study population increased from 13.0 ± 1.5 mmHg for those 6 to 7 years of age to 14.2 ± 1.4 mmHg for those 15 years of age or older (P < .001). The mean central corneal thickness (CCT) was 548.7 ± 32.1 μm, and had no difference among different age groups and gender. In univariate regression analysis, age (0.12 mmHg per 1 year old), height (0.09 mmHg per 5 cm), weight (0.02 mmHg per kg), body mass index (0.07 mmHg per 1 m/kg2), systolic blood pressure (0.06 mmHg per 5 mmHg), CCT (0.06 mmHg per 5 μm), and SE (-0.11 mmHg per 1 D) were correlated with IOP. In multivariate regression analysis, higher IOP was only associated with older ages (p = .002) and thicker CCT (p = .001).

CONCLUSION

The mean IOP in healthy rural Chinese children aged 6-18 years is about 14 mmHg, which is lower than in adults in the same locality. The mean IOP is slightly increasing with age during childhood, which is opposite to the result among adults. Age and CCT are the major independent factors associated with IOP.

Distribution and analysis of intraocular pressure and its possible association with glaucoma in children

PURPOSE

To analyze intraocular pressure (IOP) and glaucoma-associated factors in children.

METHODS

A total of 4438 children aged 7-16 years (2321 boys and 2117 girls) were included in this study. Various ophthalmologic [IOP, central corneal thickness (CCT), etc.] and demographic (body mass index, etc.) parameters were evaluated.

RESULTS

IOP increased between the ages of 7 and 9 years, peaking at 9 years. IOP increased after reaching a trough at 11 years and subsequently stabilized after 14 years. Girls exhibited thinner CCT (534.28 ± 30.84 µm vs. 537.04 ± 31.33 µm, P = 0.003), thicker lens thickness (3.56 ± 0.21 mm vs. 3.54 ± 0.20 mm, P = 0.001), shorter axial length (22.91 ± 0.93 mm vs. 23.32 ± 0.89 mm, P < 0.001), shallower anterior chamber depth (2.92 ± 0.27 mm vs. 3.00 ± 0.26 mm, P < 0.001), higher refraction (- 0.57 ± 1.48 D vs. 0.16 ± 1.35 D, P < 0.001), and higher mean corneal curvature (43.77 ± 1.39 vs. 43.03 ± 1.35, P < 0.001). Multivariable analysis assessed the following IOP-associated factors: thicker CCT [standardized correlation coefficient (SRC) = 0.201, P < 0.001), deeper anterior chamber depth (SRC = 0.059, P = 0.009), shorter axial length (SRC =  - 0.086, P = 0.036), lower mean corneal curvature (SRC =  - 0.123, P < 0.001), higher refraction (SRC =  - 0.090, P < 0.001).

CONCLUSION

IOP fluctuated in children, and a trend toward a higher mean IOP between the ages of 9 and 11 years, which stabilized after 14 years, was observed. IOP was associated with CCT, anterior chamber depth, axial length, lens thickness, mean corneal curvature, spherical equivalent, and systolic blood pressure.

TuYou-County Pediatric Eye (TYPE) study, design issues, baseline demographic characteristics, and implications: Report number 1

To report the rationale, design, and baseline demographic characteristics of TuYou-County Pediatric Eye study, which mainly aimed to determine the retinal microvascular changes with optical coherence tomography angiography (OCTA) and its association with eye abnormalities in school aged children and adolescents at suburban location in Northern China.TuYou-County Pediatric Eye study was a school-based survey conducted in TuYou-County. Multi-ethnic (Mongol, Han, and Hui) participants will be followed up for 5 years. Standardized ophthalmological examinations include visual acuity, ocular biometry, retinal photography, and OCTA. A questionnaire survey was conducted to collect variables regarding to eye disease such as parental history of eye diseases, near work, outdoor activities, living and eating habits, etc.After sampling, 687 participants were eligible for investigation, and 20 students did not attend the investigation, living 667 (response rate, 97.1%) students completed questionnaires and all ocular examinations. The average age of all participants was 14.9 ± 5.11.TYPE study is the first large-scale school-based multi-ethnic survey in suburban site of Northern China. Continuous identification of retinal microvascular changes with eye diseases will provide new insights into the control related diseases in school-age children and adolescents.

Obesity, Blood Pressure, and Intraocular Pressure: A Cross-Sectional Study in Italian Children

INTRODUCTION

Several studies in the adult population have shown that obesity is an independent risk factor for elevated intraocular pressure (IOP), whereas data in the paediatric population are sparse and controversial. The purpose of the present study is to investigate the relationship between body mass index (BMI), blood pressure (BP), and IOP in healthy school children.

METHODS

The survey was conducted among a random sample of 8-year-old Italian students. Data were collected on their health status and behaviours related to obesity (physical activity, food and drinking habits, etc.). Physical examinations, conducted at school, included measurements of height, weight, BP, and IOP.

RESULTS

Five hundred and seventy-six subjects were recruited (92.8% response rate); 42.4% were overweight or obese, 58.9% consumed inadequate daily servings of fruit and vegetables, and 87.5% were involved in sedentary activities. Elevated BP/hypertension (HTN) affected 3.6% and high IOP was revealed in 12.5% of the children. In the multivariate analysis, elevated BP/HTN was the only significant determinant of ocular HTN (OR 5.36, 95% CI 1.95-14.73, p = 0.001).

CONCLUSIONS

Our results show that high IOP affects 12.5% of 8-year-old school children and appears to be associated with high BP related to a high BMI.

Distribution of intraocular pressure in healthy Iranian children: the Shiraz Pediatric Eye Study

PURPOSE

To describe the mean and normal range of intraocular pressure (IOP) and its associations in healthy Iranian school children using the noncontact tonometer.

METHODS

In this cross-sectional study as part of the Shiraz Pediatric Eye Study, a stratified random sampling was performed among elementary school children of Shiraz, Iran. Basic demographics and socioeconomic status of households, past medical history, drug history, and eye health history were collected for each eligible student. Children underwent complete ophthalmic examination. Axial length, corneal curvature, and anterior chamber depth were measured using the IOL-Master 500.

RESULTS

Of 2,001 eligible children, 1,901 (95.0%; 3,802 eyes) with a mean age of 9.1 ± 1.6 years (standard deviation; range, 6-12 years) had reliable IOP. The mean spherical equivalent refraction was 0.5 ± 1.3 D for the right eye and 0.6 ± 1.2 D for the left eye. Mean IOP in the right eye was 15.1 ± 2.5 mm Hg (median, 15.0; range, 8.0-27.0 mm Hg); in the left eye, 15.2 ± 2.5 mm Hg (median, 15.0; range, 9.0-28.0 mm Hg). In multiple regression analyses, the mean IOP was significantly lower among asthmatic children compared to normal participants (P = 0.007). The measured IOP was significantly higher in myopic participants than hyperopic patients (P = 0.003).

CONCLUSIONS

This study provides a useful normative IOP database using the noncontact tonometer for healthy Iranian school children.

Retinal Nerve Fiber Layer Thickness in Children: The Gobi Desert Children Eye Study

Purpose

Because there is a paucity of population-based data on retinal nerve fiber layer thickness (RNFLT) for children, we measured the RNFLT and its associations in schoolchildren.

Methods

The population-based Gobi Desert Children Eye Study included all schoolchildren aged 6 to 21 years living in Ejina, Inner Mongolia. The children underwent a comprehensive ocular examination with cycloplegic refractometry and spectral-domain optical coherence tomography of the optic nerve head. The peripapillary RNFLT was measured on the optical coherence tomography images of a circular scan with a diameter of 3.4 mm.

Results

Out of 1565 participants, RNFLT data were available for 1440 (92.5%) children. The mean global RNFLT was 101.3 ± 9.2 μm in right eyes. The RNFLT was thickest in the temporal inferior sector (157.3 μm), followed by the temporal superior sector (143.8 μm), the nasal inferior sector (109.7 μm), the nasal superior sector (106.9 μm), temporal sector (85.2 μm), and the nasal sector (61.7 μm). In multivariate analysis, the RNFLT decreased with higher myopic refractive error (P < 0.001), male sex (P = 0.001), higher intraocular pressure (P = 0.002), and lower birth weight (P = 0.03). It was not significantly associated with age (P = 0.19), body mass index (P = 0.57), mean arterial blood pressure (P = 0.33), pulse rate (P = 0.28), and subfoveal choroidal thickness (P = 0.11).

Conclusions

The RNFLT in children showed a regional distribution, with the thickest part in the temporal inferior sector and the thinnest part located in the nasal sector. The overall RNLFT significantly decreased with higher myopic refractive error and male sex. In schoolchildren, in contrast to adults, the RNFLT did not decrease with older age. These findings may be considered when interpreting RNFLT data in children.

Distribution of central corneal thickness and intraocular pressure in emmetropic eyes of healthy children of Palestine: a representative cross-sectional study

AIM

To determine the distributions of central corneal thickness (CCT) and intraocular pressure (IOP) in emmetropic eyes of healthy children of Palestine.

METHODS

This representative cross sectional study included a total of 1156 eyes from 578 healthy school children aged 7-15y. Inclusion criteria included emmetropia, no previous history of ocular or systemic diseases, no previous history of contact lens use, and the availability of both eyes. CCT and IOP were measured using ultrasound pachymeter and Goldmann applanation tonometer, respectively. The relationship of the results with age and gender was investigated.

RESULTS

The mean age of school children was 11.13±2.8y. Mean CCT was 542.2±37.4 and 544.3±39.2 µm for right and left eyes, respectively. Mean IOP was 12.5±2.2 and 12.3±2.2 mm Hg for right and left eyes, respectively. A positive correlation was observed between CCT and IOP of the right eye (P<0.001, R=0.358) and CCT and IOP of the left eye (P<0.001, R=0.324). No significant differences were observed in CCT and IOP due to age or gender (P>0.05). There were significant differences in mean CCT and IOP between right and left eyes (P=0.004, P=0.001, respectively).

CONCLUSION

A population profile of CCT and IOP is established in Palestinian children for the first time. Mean CCT is comparable to some studies but differ from others. Mean IOP is considerably lower than that of majority children of other ethnic groups. Intereye difference of more than 36 µm in CCT, and 5 mm Hg in IOP should prompt evaluation for potential ocular disorders.

Ocular Signs Related to Overweight and Arterial Hypertension in Children: A Systematic Review

Background:

The ocular effects of obesity and hypertension need to be established and can be used as prognostic markers.

Objective:

To estimate the prevalence of ophthalmological alterations in children and adolescents who are overweight and/or have SAH.

Methods:

The database for this study included all observational studies (CS, cohort, case-control and “baseline” description of randomized clinical trials) with children and/or adolescents who were overweight, obese or had SAH and that measured ophthalmological alterations.

Results:

Comparative studies with healthy children demonstrated positive association between body adiposity with retinal venular dilation, and SAH with retinal arteriolar narrowing. Different retinal fundus cameras and computer-assisted programs to evaluate the retinal vessels, variations in the methods of analysis, adjustments, populations, were the main arguments against formal meta-analysis. The heterogeneity was too high (I² >90%, in fixed or randomized effects), and the lack of linearity, normal distribution and homoscedasticity did not recommend meta-regression.

Conclusion:

Obesity and SAH show associations with ophthalmological alterations, especially with retinal vessel diameter. Lack of standardization does not allow a quantitative evaluation.

Choroidal thickness in school children: The Gobi Desert Children Eye Study

Purpose

To investigate choroidal thickness (CT) and its associations in children in a school-based study.

Methods

The cross-sectional school-based Gobi Desert Children Eye Study included 1565 out of 1911 (81.9%) eligible children from all schools in the oasis region of Ejina in the Gobi Desert. A detailed ophthalmic examination was performed, including spectral-domain optical coherence tomography with enhanced depth imaging for CT measurement.

Results

CT measurements were available for 1463 (93.5%) students (mean age: 11.8±3.5 years; range:7–21 years). Mean subfoveal choroidal thickness (SFCT) was 282±49μm. CT was thickest at 1000μm temporal to the fovea (286±49μm), followed by the subfoveal region (282±49 μm; P<0.001), the region at 2500μm temporal to the fovea (278±49μm), the region at 1000μm nasal to the fovea (254±49μm;P<0.001), and the region at 2500μm nasal to the fovea (197±50μm;P<0.001). In cross-sectional analysis, the mean SFCT increased with age from 288μm at 7 years of age to 304μm at 11 years, and then decreased to 258 μm at 18 years. In multivariate analysis, thicker SFCT was associated (regression coefficient r:0.38) with higher hyperopic refractive error (P<0.001;standardized regression coefficient beta:0.31;non-standardized regression coefficient B:7.61;95% confidence intervals (CI):6.29,8.93), younger age (P<0.001;beta:-0.10;B:-1.39;95%CI:-2.14,-0.64), male gender (P = 0.03;beta:-0.05;B:-5.33;95%CI:-10.1,-0.53), higher corneal refractive power (P<0.001;beta:0.12;B:3.68;95%CI:2.12,5.24), and non-Han Chinese ethnicity (P = 0.03;beta:0.05;B:6.16;95%CI:0.50,11.8). Ratio of CT(1000μm nasal to fovea)/SFCT (0.90±0.06;range:0.66,1.23) and ratio of CT(2500μm nasal to fovea)/SFCT (0.70±0.13;range:0.28,1.23) decreased with older age (P = 0.01;and P = 0.001, respectively), while ratio of CT(1000μm temporal to fovea)/SFCT (1.02±0.06;range:0.56,1.37) and ratio of CT(2500μm temporal to fovea)/SFCT (0.99±0.11;range:0.54,1.84) increased with older age (both P<0.001). Time spent outdoors or indoors was not significantly associated with CT-related parameter in multivariate analysis.

Conclusions

In contrast to SFCT in adults and despite elongating axial length, SFCT in children increased in cross-sectional analysis with older age (up to 11 years of age) and then started to decrease with further ageing. It suggests an increase in choroidal volume up to the age of 11 years. In children, the choroid was thickest at 1000μm temporal to the fovea, followed by the subfoveal region, and this difference significantly increased with older age. In contrast, CT nasal to the fovea in relationship to SFCT decreased with older age. CT was independent of lifestyle-associated parameters.

Pre- and Postcycloplegic Refractions in Children and Adolescents

Purpose

To determine the difference between cycloplegic and non-cycloplegic refractive error and its associated factors in Chinese children and adolescents with a high prevalence of myopia.

Methods

A school-based study including 1565 students aged 6 to 21 years was conducted in 2013 in Ejina, Inner Mongolia, China. Comprehensive eye examinations were performed. Pre-and postcycloplegic refractive error were measured using an auto-refractor. For cycloplegic refraction, one drop of topical 1.0% cyclopentolate was administered to each eye twice with a 5-minute interval and a third drop was administered 15 minutes after the second drop if the pupil size was less than 6 mm or if the pupillary light reflex was still present.

Results

Two drops of cyclopentolate were found to be sufficient in 59% of the study participants while the other 41% need an additional drop. The prevalence of myopia was 89.5% in participants aged over 12 years and 68.6% in those aged 12 years or younger (P<0.001). When myopia was defined as spherical equivalent (SE) of less than -0.5 diopter (D), the prevalence estimates were 76.7% (95% confidence interval [CI] 74.6–78.8) and 54.1% (95%CI 51.6–56.6) before and after cycloplegic refraction, respectively. When hyperopia was defined as SE of more than 0.5D, the prevalence was only 2.8% (95%CI 1.9–3.6) before cycloplegic refraction while it was 15.5% (95%CI 13.7–17.3) after cycloplegic refraction. Increased difference between cycloplegic and non-cycloplegic refractive error was associated with decreased intraocular pressures (P = 0.01).

Conclusions

Lack of cycloplegia in refractive error measurement was associated with significant misclassifications in both myopia and hyperopia among Chinese children and adolescents. Decreased intraocular pressure was related to a greater difference between cycloplegic and non-cycloplegic refractive error.

Axial Length and Associated Factors in Children: The Shandong Children Eye Study

PURPOSE

To investigate ocular axial length (AL) in Chinese children.

METHODS

The Shandong Children Eye Study included 6,364 children aged 4-18 years.

RESULTS

Longer AL (mean 23.45 ± 1.20 mm, range 18.80-28.59 mm) was associated (multivariate analysis; correlation coefficient r2: 0.61) with older age (p < 0.001, standardized correlation coefficient β = 0.35, unstandardized regression coefficient B = 0.13, 95% confidence interval [CI] 0.12, 0.15), male gender (p < 0.001, β = -0.24, B = -0.10, 95% CI -0.29, -0.19), urban region (p < 0.001, β = 0.10, B = 0.25, 95% CI 0.20, 0.31), body height (p < 0.001, β = 0.22, B = 0.02, 95% CI 0.01, 0.02), maternal education (p < 0.001, β = 0.07, B = 0.07, 95% CI 0.05, 0.10), paternal myopia (p < 0.001, β = 0.09, B = 0.26, 95% CI 0.20, 0.33), maternal myopia (p < 0.001, β = 0.08, B = 0.23, 95% CI 0.17, 0.30), more time spent indoors reading/writing (p < 0.001, β = 0.05, B = 0.03, 95% CI 0.02, 0.04), less time spent outdoors (p = 0.005, β = -0.03, B = -0.01, 95% CI -0.02, -0.003), longer corneal curvature radius (p < 0.001, β = 0.36, B = 1.63, 95% CI 1.53, 1.74) and higher intraocular pressure (p = 0.008, β = 0.03, B = 0.01, 95% CI 0.004, 0.02). High axial myopia (AL ≥26.0 mm) present in 202 children (3.4 ± 0.2%, 95% CI 2.92, 3.84) was associated with less time spent outdoors (p = 0.002, odds ratio 0.92, 95% CI 0.87, 0.97) in multivariate analysis.

CONCLUSIONS

In children in the less developed Eastern Chinese province of Shandong, the prevalence of high axial myopia was >10% among 16-year-olds. A modifiable factor associated with higher prevalence of high axial myopia was less time spent outdoors.