Development of Refractive Parameters in 3- to 6-Year-Old Children and Its Application in Myopia Prediction and Intervention Guidance

Objective. To investigate refractive development and prevalence of myopia in children aged 3-6 years in Hebei Province, China, and to explore the developmental law of refraction, so as to clinically guide the prediction and intervention of myopia. Methods. In May 2019, a total of 6120 people were inspected in 68 kindergartens in 11 cities in Hebei Province. Child refractive refraction was checked under noncycloplegia using a handheld binocular vision screener (SW-800, SUOER, Tianjin, China). Axial length (AL) and corneal radius of curvature (CR) were measured using an ocular biometry (IOLMaster 500, Carl Zeiss, Germany). Myopia was defined as spherical equivalent SE ≤ − 0.75 D . Results. A total of 5506 children aged 3-6 years met the criteria and were included in the statistical analysis. The prevalence of myopia was 3.49% (1.93% at age 3, 2.90% at age 4, 3.78% at age 5, and 3.88% at age 6). Overall, the mean SE was + 0.67 ± 1.05 D ( + 0.81 ± 1.00 D at age 3, + 0.79 ± 1.05 D at age 4, + 0.67 ± 1.08 D at age 5, and + 0.13 ± 1.01 D at age 6); the mean CR was 7.76 ± 0.26 mm ( 7.78 ± 0.26 mm at age3, 7.75 ± 0.25 mm at age 4, 7.77 ± 0.26 mm at age 5, and 7.76 ± 0.25 mm at age 6); the mean AL was 22.31 ± 0.73 mm ( 21.98 ± 0.63 mm at age 3, 22.12 ± 0.69 mm at age 4, 22.34 ± 0.73 mm at age 5, and 22.49 ± 0.73 mm at age 6). Conclusions. Prevalence of myopia increases with age in children aged 3-6 years in Hebei, China. With the increase of age, CR is basically stable, and AL increases gradually. AL/CR, which is closely related to SE, can be used as an indicator to predict myopia and guide clinical work.

Download Full-text

The Role of Axial Length-Corneal Radius of Curvature Ratio in Refractive State Categorization in a Nigerian Population

ISRN Ophthalmology ◽

10.5402/2011/138941 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 8

Author(s):

Eghosasere Iyamu ◽

Joy Iyamu ◽

Christian Izuchukwu Obiakor

Keyword(s):

Axial Length ◽

Inverse Correlation ◽

Radius Of Curvature ◽

Spherical Equivalent ◽

Refractive State ◽

Spherical Equivalent Refraction ◽

Nigerian Population ◽

Corneal Radius ◽

The Mean

The aim of this study was to investigate the association of axial length (AL)/corneal radius of curvature (CRC) ratio (AL/CRC) with spherical equivalent refractive state (SER) in young adults. A total of seventy () subjects consisting of 31 males and 39 females participated in this study. Subjects were categorized into emmetropia, hyperopia and myopia using the spherical equivalent refraction. The axial length was measured with I-2100 A-Scan ultrasonography/Biometer (CIMA Technology, USA), the corneal radius of curvature with Bausch & Lomb H-135A (Bausch & Lomb Corp., USA), and the refractive state by static retinoscopy and subjective refraction. The mean AL, CRC and AL/CRC ratio of all subjects were 23.74 ± 0.70 mm, 7.84 ± 0.19 mm, and 3.03 ± 0.14, respectively. Myopes had significantly longer AL, steeper CRC and higher AL/CRC ratio than the emmetropes and hyperopes. There was statistically significant inverse correlation between AL and CRC (, ), SER (, ), and between SER and AL/CRC (, ). A significant positive correlation was found between CRC and SER (, ). The categorization of the refractive state of an individual is better done by using the AL/CRC ratio index.

Download Full-text

Simultaneous Changes in Astigmatism with Noncycloplegia Refraction and Ocular Biometry in Chinese Primary Schoolchildren

Journal of Ophthalmology ◽

10.1155/2019/5613986 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8

Author(s):

Yaoyao Lin ◽

Dandan Jiang ◽

Chunchun Li ◽

Xiao Chang ◽

Balamurali Vasudevan ◽

...

Keyword(s):

Odds Ratio ◽

Radius Of Curvature ◽

Spherical Equivalent ◽

Ocular Biometry ◽

Spherical Equivalent Refraction ◽

Primary Schoolchildren ◽

Corneal Radius ◽

Independent Risk Factors ◽

Clinically Significant

Purpose. To assess the changing profile of astigmatism in Chinese schoolchildren and the association between astigmatism changes and ocular biometry. Methods. We examined and followed up 1,463 children aged 6–9 years from Wenzhou, China. We measured noncycloplegic refraction twice each year and tested axial length (AL) and corneal radius of curvature (CRC) annually for two years. We defined clinically significant astigmatism (CSA) as ≤−0.75 diopter (D) and non-CSA astigmatism as ≤0 to >−0.75 D. Results. Prevalence of CSA at baseline was 22.4% (n = 327) and decreased to 20.3% (n = 297) at the two-year follow-up (P=0.046). Ninety-two (8.1%) non-CSA children developed CSA. In multiple regression, after adjusting for age, gender, baseline cylinder refraction, and axis, children who had longer baseline ALs (>23.58 mm; odds ratio (OR) = 5.19, 95% confidence interval (CI): 2.72–9.90) and longer baseline AL/CRC ratio (>2.99, OR = 4.99, 95% CI: 2.37–10.51) were more likely to develop CSA after two years. Four-hundred and two (27.5%) children had increased astigmatism, 783 (53.5%) had decreased, and 278 (19.0%) had no change during the two-year follow-up. Children with increased astigmatism had longer baseline ALs (23.33 mm, P<0.001), higher AL/CRC ratios (2.99 mm, P<0.001), and more negative spherical equivalent refraction (SER) (−0.63 D, P<0.001) compared with the decreased and no astigmatism change subgroups. Also, children in the increased astigmatism subgroup had more AL growth (0.68 mm, P<0.001), higher increases in AL/CRC ratio (0.08, P<0.001), and more negative SER change (−0.86 D, P<0.001) compared with the decreased and no astigmatism change subgroups. Conclusions. The prevalence of astigmatism decreased slightly over the two-year study period. Longer ALs and higher AL/CRC ratios were independent risk factors for developing CSA. Increased astigmatism was associated with AL growth, AL/CRC ratio increases, and the development of myopia. This trial is registered with ChiCTR1800019915.

Download Full-text

The Correlation of Cycloplegic Refraction with Corneal Radius of Curvature-Adjusted Axial Length in Chinese Preschoolers

10.21203/rs.3.rs-395611/v1 ◽

2021 ◽

Author(s):

Xiao-hong Zhou ◽

Yian Li ◽

Wei Wang ◽

Chen-hao Yang

Keyword(s):

Axial Length ◽

Chinese Children ◽

Radius Of Curvature ◽

Refractive Errors ◽

Spherical Equivalent ◽

Spherical Equivalent Refraction ◽

Curvature Coefficient ◽

Corneal Radius ◽

The Mean ◽

And Gender

Abstract Background: In order to master the refractive status and detect severe refractive errors quickly and effectively, this study aimed to investigate the association of axial length after adjusting for corneal radius of curvature with refraction in a group of Chinese preschoolers. Methods: Retrospective review of 716 Chinese children aged from 3 to 6 years, who underwent cycloplegic optometry with 1% atropine eye gel in the ophthalmology department of Children’s Hospital of Fudan University, National Children’s Medical Center in Shanghai. Meanwhile axial length, corneal radius of curvature and cycloplegic autorefraction were obtained and axial length/corneal radius of curvature (AL/CR) ratio was calculated. The correlations of spherical equivalent refraction (SER) with axial length, corneal radius of curvature, AL/CR ratio and corneal radius of curvature-adjusted axial length were analyzed. Results: Only data from the right eye were included in this analysis. Among 716 eyes of 716 Chinese preschoolers, the mean (±SD) SER was 2.28±2.41 diopters (D), of which hyperopia, emmetropia, myopia were 84.64%, 8.54%, 6.84%, respectively. The mean(±SD) axial length, corneal radius of curvature and AL/CR ratio were 21.89±1.01mm, 7.76±0.27 mm, and 2.82±0.13, respectively. The SER was highly negative correlated with both axial length (coefficient –0.722) and AL/CR ratio (coefficient-0.814), and weakly correlated with corneal radius of curvature (coefficient 0.090) and gender(coefficient 0.093). Axial length was weakly correlated with age and gender(coefficient 0.232 and 0.268, respectively), but moderately correlated with corneal radius of curvature (coefficient 0.424). After adjusting for corneal radius of curvature, the correlation coefficient between SER and axial length significantly increased to-0.918. Conclusion: In the samples of 716 3-to 6-year-old Chinese children, axial length was moderately correlated with corneal radius of curvature. After adjusting for corneal radius of curvature, refraction was closely correlated with axial length than axial length alone and AL/CR ratio. Therefore, corneal radius of curvature-adjusted axial length might be a useful tool for pediatric ophthalmologists to detect refractive errors. Key Words: spherical equivalent refraction; corneal radius of curvature; adjusted; axial length; preschoolers.

Download Full-text

CHANGE OF SOME INDICATORS OF EYES BEFORE AND AFTER SURGICAL TREATMENT PHACO CATARACT SENIORS IN HUE UNIVERSITY HOSPITAL

Journal of Medicine and Pharmacy ◽

10.34071/jmp.2014.6.11 ◽

2015 ◽

pp. 81-85

Author(s):

Thi Dieu Tram Phan ◽

Van Nam Phan

Keyword(s):

Anterior Chamber Depth ◽

University Hospital ◽

Radius Of Curvature ◽

Postoperative Astigmatism ◽

First Choice ◽

Before And After ◽

Corneal Radius ◽

The Mean ◽

Phacoemulsification Cataract Surgery ◽

Cataract Patients

Objective: Phacoemulsification cataract surgery is the method applyied commonly and the first choice of Ophthalmologist. Materials and Method: We study comprised 49 eyes of 42 cataract patients for Phacoemulsification at Hue Hospital University from 5/2013 to 4/2014 with within 3 months after surgery. Result: 3 months after surgery, the visual acuity ≤ 4/10 accounted for 75,5%, corrected vision ≥ 4/10 accounted for 95,9%. The mean postoperative astigmatism was 1,02D ± 0,58, stable and does not change much compared to before surgery. The mean intraocular pressure (IOP) increased to 10,51mmHg ± 1,77 at 3 months postoperatively,the IOP was 3,9mmHg lower at 3 months than preoperative. Anterior chamber depth (ACD) increased by 1,0mm deeper than before surgery. Corneal refractive power increased 0,43D. Corneal radius of curvature decreased 0,11mm by 3 month postoperatively. Key words: Cataract, Phacoemulsification.

Download Full-text

Evaluation of the Relationships between Corneal Parameters, Ocular Biometry, and Myopia Magnitude

Sains Malaysiana ◽

10.17576/jsm-2021-5010-20 ◽

2021 ◽

Vol 50 (10) ◽

pp. 3077-3084

Author(s):

Mohd Izzuddin Hairol ◽

Norlaili Arif ◽

Pui Theng Yong ◽

Mariah Asem Shehadeh Saleh Ali ◽

Nik Nor Adlina Nik Idris ◽

...

Keyword(s):

Axial Length ◽

Corneal Thickness ◽

Anterior Chamber Depth ◽

Radius Of Curvature ◽

Corneal Curvature ◽

Ocular Biometry ◽

Corneal Asphericity ◽

Corneal Radius ◽

The Difference ◽

The Relationship

Axial length of the eye correlates with the magnitude of myopia. However, there are conflicting reports on the relationship between certain corneal parameters with myopia magnitude. The objective of this study was to compare ocular biometry and corneal parameters between emmetropic and myopic groups. Participants (n=127) were categorized as emmetropia (spherical equivalent, SE, ±0.50D), low myopia (-0.75D≤SE<-6.00D) and high myopia (SE≥-6.00D). The difference in axial length, anterior chamber depth, and vitreous chamber depth between emmetrope, low myope, and high myope were highly significant (one-way ANOVA, all p<0.001) with significant correlations between SE and all these parameters (simple regressions, all p<0.001). However, central corneal thickness, corneal radius of curvature, and corneal asphericity between these groups, and the correlations between the ocular parameters with SE were not significantly different (all p>0.05). Corneal curvature correlated significantly with axial length (p=0.001) but not with myopia magnitude (p=0.91). Rather than myopia magnitude, axial length appears to be more sensitive to detect changes in corneal curvature in myopes. In conclusion, myopic patients’ axial length should be carefully considered for interventions that involve the cornea, such as orthokeratology and refractive surgery.

Download Full-text

Relationship between Myopia Progression and School Entrance Age: A 2.5-Year Longitudinal Study

Journal of Ophthalmology ◽

10.1155/2021/7430576 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Linjie Liu ◽

Dandan Jiang ◽

Chunchun Li ◽

Yaoyao Lin ◽

Wenzhe Zhou ◽

...

Keyword(s):

Anterior Chamber Depth ◽

Radius Of Curvature ◽

Spherical Equivalent ◽

Biological Structure ◽

Myopia Progression ◽

School Entrance ◽

Corneal Radius ◽

Grade 3 ◽

Automatic Refractometer ◽

Entrance Age

Objective. To investigate the association between myopia progression and school entrance age among Chinese schoolchildren and to suggest a more appropriate school age. Methods. 1,463 children aged six to nine years from Wenzhou, China, were examined and followed up for two and a half consecutive years. Their noncycloplegic refraction was measured twice each year by using an automatic refractometer; axial length (AL) and corneal radius of curvature (CRC) were tested annually by using the IOLMaster for 2.5 years. The questionnaires were completed by the children to collect detailed information regarding risk factors. Here, myopia is defined as a spherical equivalent less than −1.0D. Results. The changes in spherical equivalent (SE) of 7-year-old children in grade 1 and grade 2 were −0.45D and -0.56D, while changes in AL were 0.59 mm and 0.62 mm, respectively. The SE changes of 8-year-old children in grade 2 and grade 3 were −0.54D and −0.75D; meanwhile, the AL changes were 0.57 mm and 0.61 mm, respectively. Significant statistical differences were observed in ocular biological structure parameters, except for corneal radius of curvature (CRC) or anterior chamber depth (ACD), among children with the same age in different grades during this study. The prevalence of myopia was also significantly higher in higher grades for children with same age. Conclusions. Myopia is related to children’s school entrance age. Children who start school in an earlier age are more likely to suffer from myopia, and the progression of myopia can be considerably faster. Therefore, it is recommended to enter school after the age of 7.

Download Full-text

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

BMC Ophthalmology ◽

10.1186/s12886-021-02001-6 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ruxia Pei ◽

Zhuzhu Liu ◽

Hua Rong ◽

Liqiong Zhao ◽

Bei Du ◽

...

Keyword(s):

Young Adults ◽

Epidemiological Studies ◽

Spherical Equivalent ◽

Ocular Biometry ◽

Significant Difference ◽

Before And After ◽

Registration Number ◽

The Mean ◽

Chinese Young Adults ◽

Medical University

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

Download Full-text

A Randomized Clinical Trial Using Cyclopentolate and Tropiacmide to Compare Cycloplegic Refractions in Chinese Young Adults

10.21203/rs.3.rs-271275/v1 ◽

2021 ◽

Author(s):

Ruxia Pei ◽

Zhuzhu Liu ◽

Hua Rong ◽

Liqiong Zhao ◽

Bei Du ◽

...

Keyword(s):

Young Adults ◽

Epidemiological Studies ◽

Refractive Errors ◽

Spherical Equivalent ◽

Ocular Biometry ◽

Significant Difference ◽

Before And After ◽

The Mean ◽

Chinese Young Adults ◽

Medical University

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

Download Full-text