scholarly journals Effect of Biomechanical Properties on Myopia: a Study of New Corneal Biomechanical Parameters

2020 ◽  
Author(s):  
Fang Han ◽  
Mengdi Li ◽  
Pinghui Wei ◽  
Jiaonan Ma ◽  
Vishal Jhanji ◽  
...  
Keyword(s):  
High Myopia ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Spherical Equivalent ◽  
Stiffness Parameter ◽  
P Values ◽  
Material Stiffness ◽  
Deflection Amplitude ◽  
Biomechanical Parameters ◽  
The Mean

Abstract Background: To investigate assess the corneal stress-strain index (SSI), which is a marker for material stiffness and corneal biomechanical parameters , in myopic eyes. Methods: A total of 105 4 6 myopic patients were included in this study. Corneal v isuali s ation Scheimpflug t echnology Corvis ST was used to measure the SSI. Corneal biomechanics w ere as evaluated assessed using the first and second applanation time s (A1- time and A2-time s ), maximum deflection amplitude (DefAmax), deflection area (HCDefArea) , and peak distance at highest concavity peak distance (HC-PD), HC-time, HC-DefA, and HC-PD), integrated radius (IR) , whole eye movement (WEM), stiffness parameter (SP), biomechanically corrected intraocular pressure (BIOP) , and Corvis b iomechanical i ndex (CBI). Scheimpflug tomography was used to obtain the mean keratometery (Km) and central corneal thickness (CCT). All participants were divided into two groups according to the spherical equivalent (SE) (low myopia: SE ≤ 3.00D and high myopia: SE ≥ 6.00D). Results: The mean SSI value was 0.854±0.004. The SSI ha d a positive correlation with A1-time ((r=0.272), HC-time (r=0.218), WEM (r=0.288), SP (r=0.316) , CBI (r=0.199 ) , CCT (r=0.125), BIOP (r=0.230) , and SE (r=0.313) (all p - values＜0.01) . The SSI had a negative correlation with HCDefA (r=-0.721), HCDefArea (r=-0.665), HC-PD(r=-0.597), IR (r=-0.555), DefAmax (r=-0.564) , and Km (r=-0.103) (all p - values＜0.01). There were significant differences in SSI (t=8.960, p＜0.01) and IR (t=-3.509, p＜0.01) between the low and high myopia groups group and high myopia group . Conclusions: In different grades of myopia, the SSI values were lower in eyes with higher SE spherical equivalent s . It indicates that the mechanical strength of the cornea may be compromise d in high myopia. The SSI was positively correlated with the spherical equivalent , and it It may provide a new way to study the mechanism of myopia.

scholarly journals Effect of Biomechanical Properties on Myopia: a Study of New Corneal Biomechanical Parameters

2020 ◽  
Author(s):  
Fang Han ◽  
Mengdi Li ◽  
Pinghui Wei ◽  
Jiaonan Ma ◽  
Vishal Jhanji ◽  
...  
Keyword(s):  
High Myopia ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Spherical Equivalent ◽  
Stiffness Parameter ◽  
P Values ◽  
Material Stiffness ◽  
Deflection Amplitude ◽  
Biomechanical Parameters ◽  
The Mean

Abstract Background: To investigate corneal stress-strain index (SSI), a marker for material stiffness and corneal biomechanical parameters in myopic eyes.Methods: A total of 1056 myopic patients were included in this study. Corvis ST was used to measure SSI. Corneal biomechanics was evaluated using the first and second applanation time (A1-time and A2-time), maximum deflection amplitude (DefAmax), deflection area(HCDefArea)and peak distance at highest concavity (HC-time, HC-DefA, and HC-PD), integrated radius (IR) whole eye movement (WEM), stiffness parameter (SP), biomechanically corrected intraocular pressure (BIOP), and Corvis Biomechanical Index (CBI). Scheimpflug tomography was used to obtain mean keratometery (Km) and central corneal thickness (CCT). All participants were divided into two groups according spherical equivalent (SE) (low myopia: SE≤3.00D and high myopia: SE ≥ 6.00D).Results: The mean SSI value was 0.854±0.004. The SSI has positive correlation with A1-time((r=0.272), HC-time (r=0.218), WEM(r=0.288),SP(r=0.316)，CBI(r=0.199)，CCT (r=0.125), BIOP(r=0.230)and SE (r=0.313)(all p values＜0.01) . The SSI had a negative correlation with HCDefA (r=-0.721), HCDefArea (r=-0.665),HC-PD(r=-0.597),IR (r=-0.555), DefAmax (r=-0.564)and Km (r=-0.103) (all p values＜0.01).There were significant differences in SSI (t=8.960, p＜0.01) and IR(t=-3.509, p＜0.01)between low myopia group and high myopia group.Conclusions: In different grades of myopia, the SSI values were lower in eyes with higher spherical equivalent. It indicates that the mechanical strength of the cornea may compromise in high myopia. The SSI was positively correlated with the spherical equivalent and It may provide a new way to study the mechanism of myopia.

scholarly journals Effect of biomechanical properties on myopia: a study of new corneal biomechanical parameters

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Fang Han ◽  
Mengdi Li ◽  
Pinghui Wei ◽  
Jiaonan Ma ◽  
Vishal Jhanji ◽  
...  
Keyword(s):  
High Myopia ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Spherical Equivalent ◽  
Stiffness Parameter ◽  
P Values ◽  
Material Stiffness ◽  
Deflection Amplitude ◽  
Biomechanical Parameters ◽  
The Mean

Abstract Background To assess the corneal stress-strain index (SSI), which is a marker for material stiffness and corneal biomechanical parameters, in myopic eyes. Methods A total of 1054 myopic patients were included in this study. Corneal visualisation Scheimpflug technology was used to measure the SSI. Corneal biomechanics were assessed using the first and second applanation times (A1-and A2-times); maximum deflection amplitude (DefAmax); deflection area (HCDefArea); the highest concavity peak distance (HC-PD), time (HC-time), and deflection amplitude (HC-DefA); integrated radius (IR); whole eye movement (WEM); stiffness parameter (SP-A1;, biomechanically corrected intraocular pressure (BIOP); and Corvis biomechanical index (CBI). Scheimpflug tomography was used to obtain the mean keratometery (Km) and central corneal thickness (CCT). According to the spherical equivalent (SE) (low myopia: SE ≥ − 3.00D and high myopia: SE ≤ − 6.00D.), the suitable patients were divided into two groups. Results The mean SSI value was 0.854 ± 0.004. The SSI had a positive correlation with A1-time ((r = 0.272), HC-time (r = 0.218), WEM (r = 0.288), SP-A1 (r = 0.316), CBI (r = 0.199), CCT (r = 0.125), bIOP (r = 0.230), and SE (r = 0.313) (all p-values<0.01). The SSI had a negative correlation with HCDefA (r = − 0.721), HCDefArea (r = − 0.665), HC-PD(r = − 0.597), IR (r = − 0.555), DefAmax (r = − 0.564), and Km (r = − 0.103) (all p-values<0.01). There were significant differences in SSI (t = 8.960, p<0.01) and IR (t = − 3.509, p<0.01) between the low and high myopia groups. Conclusions In different grades of myopia, the SSI values were lower in eyes with higher SEs. It indicates that the mechanical strength of the cornea may be compromised in high myopia. The SSI was positively correlated with the spherical equivalent, and it may provide a new way to study the mechanism of myopia.

scholarly journals Effect of Biomechanical Properties on Myopia: a Study of New Corneal Biomechanical Parameters

2020 ◽  
Author(s):  
Fang Han ◽  
Mengdi Li ◽  
Pinghui Wei ◽  
Jiaonan Ma ◽  
Vishal Jhanji ◽  
...  
Keyword(s):  
High Myopia ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Spherical Equivalent ◽  
Stiffness Parameter ◽  
P Values ◽  
Material Stiffness ◽  
Deflection Amplitude ◽  
Biomechanical Parameters ◽  
The Mean

Abstract Background: To assess the corneal stress-strain index (SSI), which is a marker for material stiffness and corneal biomechanical parameters, in myopic eyes.Methods: A total of 1054 myopic patients were included in this study. Corneal visualisation Scheimpflug technology was used to measure the SSI. Corneal biomechanics were assessed using the first and second applanation times (A1-and A2-times); maximum deflection amplitude (DefAmax); deflection area (HCDefArea); the highest concavity peak distance (HC-PD), time (HC-time), and deflection amplitude (HC-DefA); integrated radius (IR); whole eye movement (WEM); stiffness parameter (SP-A1;, biomechanically corrected intraocular pressure (BIOP); and Corvis biomechanical index (CBI). Scheimpflug tomography was used to obtain the mean keratometery (Km) and central corneal thickness (CCT). According to the spherical equivalent (SE) (low myopia: SE ≥ -3.00D and high myopia: SE ≤ -6.00D.), the suitable patients were divided into two groupsResults: The mean SSI value was 0.854±0.004. The SSI had a positive correlation with A1-time ((r=0.272), HC-time (r=0.218), WEM (r=0.288), SP-A1 (r=0.316), CBI (r=0.199), CCT (r=0.125), bIOP (r=0.230), and SE (r=0.313) (all p-values＜0.01) . The SSI had a negative correlation with HCDefA (r=-0.721), HCDefArea (r=-0.665), HC-PD(r=-0.597), IR (r=-0.555), DefAmax (r=-0.564), and Km (r=-0.103) (all p-values＜0.01). There were significant differences in SSI (t=8.960, p＜0.01) and IR (t=-3.509, p＜0.01) between the low and high myopia groups.Conclusions: In different grades of myopia, the SSI values were lower in eyes with higher SEs. It indicates that the mechanical strength of the cornea may be compromised in high myopia. The SSI was positively correlated with the spherical equivalent, and it may provide a new way to study the mechanism of myopia.

scholarly journals Corneal Biomechanical Parameters and Central Corneal Thickness in Glaucoma Patients, Glaucoma Suspects, and a Healthy Population

2021 ◽  
Vol 10 (12) ◽  
pp. 2637
Author(s):  
Mª. Ángeles del Buey-Sayas ◽  
Elena Lanchares-Sancho ◽  
Pilar Campins-Falcó ◽  
María Dolores Pinazo-Durán ◽  
Cristina Peris-Martínez
Keyword(s):  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Mean Difference ◽  
The Other ◽  
Control Group ◽  
Healthy Population ◽  
Diagnostic Categories ◽  
Significant Difference ◽  
Biomechanical Parameters ◽  
The Mean

Purpose: To evaluate and compare corneal hysteresis (CH), corneal resistance factor (CRF), and central corneal thickness (CCT), measurements were taken between a healthy population (controls), patients diagnosed with glaucoma (DG), and glaucoma suspect patients due to ocular hypertension (OHT), family history of glaucoma (FHG), or glaucoma-like optic discs (GLD). Additionally, Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated IOP (IOPcc) were compared between the different groups of patients. Methods: In this prospective analytical-observational study, a total of 1065 patients (one eye of each) were recruited to undergo Ocular Response Analyzer (ORA) testing, ultrasound pachymetry, and clinical examination. Corneal biomechanical parameters (CH, CRF), CCT, IOPg, and IOPcc were measured in the control group (n = 574) and the other groups: DG (n = 147), FHG (n = 78), GLD (n = 90), and OHT (n = 176). We performed a variance analysis (ANOVA) for all the dependent variables according to the different diagnostic categories with multiple comparisons to identify the differences between the diagnostic categories, deeming p < 0.05 as statistically significant. Results: The mean CH in the DG group (9.69 mmHg) was significantly lower compared to controls (10.75 mmHg; mean difference 1.05, p < 0.001), FHG (10.70 mmHg; mean difference 1.00, p < 0.05), GLD (10.63 mmHg; mean difference 0.93, p < 0.05) and OHT (10.54 mmHg; mean difference 0.84, p < 0.05). No glaucoma suspects (FHG, GLD, OHT groups) presented significant differences between themselves and the control group (p = 1.00). No statistically significant differences were found in the mean CRF between DG (11.18 mmHg) and the control group (10.75 mmHg; mean difference 0.42, p = 0.40). The FHG and OHT groups showed significantly higher mean CRF values (12.32 and 12.41 mmHg, respectively) than the DG group (11.18 mmHg), with mean differences of 1.13 (p < 0.05) and 1.22 (p < 0.001), respectively. No statistically significant differences were found in CCT in the analysis between DG (562 μ) and the other groups (control = 556 μ, FHG = 576 μ, GLD = 569 μ, OHT = 570 μ). The means of IOPg and IOPcc values were higher in the DG patient and suspect groups than in the control group, with statistically significant differences in all groups (p < 0.001). Conclusion: This study presents corneal biomechanical values (CH, CRF), CCT, IOPg, and IOPcc for diagnosed glaucoma patients, three suspected glaucoma groups, and a healthy population, using the ORA. Mean CH values were markedly lower in the DG group (diagnosed with glaucoma damage) compared to the other groups. No significant difference was found in CCT between the DG and control groups. Unexpectedly, CRF showed higher values in all groups than in the control group, but the difference was only statistically significant in the suspect groups (FHG, GLD, and OHT), not in the DG group.

scholarly journals Corneal Biomechanical Properties in Varying Severities of Myopia

2021 ◽  
Vol 8 ◽  
Author(s):  
Mohammad-Reza Sedaghat ◽  
Hamed Momeni-Moghaddam ◽  
Abbas Azimi ◽  
Zohreh Fakhimi ◽  
Mohammed Ziaei ◽  
...  
Keyword(s):  
Axial Length ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Cross Sectional Study ◽  
Geometrical Parameters ◽  
Cross Sectional ◽  
Corvis St ◽  
Multiple Parameters ◽  
Inverse Radius ◽  
Biomechanical Parameters

Purpose: To investigate corneal biomechanical response parameters in varying degrees of myopia and their correlation with corneal geometrical parameters and axial length.Methods: In this prospective cross-sectional study, 172 eyes of 172 subjects, the severity degree of myopia was categorized into mild, moderate, severe, and extreme myopia. Cycloplegic refraction, corneal tomography using Pentacam HR, corneal biomechanical assessment using Corvis ST and Ocular Response Analyser (ORA), and ocular biometry using IOLMaster 700 were performed for all subjects. A general linear model was used to compare biomechanical parameters in various degrees of myopia, while central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were considered as covariates. Multiple linear regression was used to investigate the relationship between corneal biomechanical parameters with spherical equivalent (SE), axial length (AXL), bIOP, mean keratometry (Mean KR), and CCT.Results: Corneal biomechanical parameters assessed by Corvis ST that showed significant differences among the groups were second applanation length (AL2, p = 0.035), highest concavity radius (HCR, p &lt; 0.001), deformation amplitude (DA, p &lt; 0.001), peak distance (PD, p = 0.022), integrated inverse radius (IR, p &lt; 0.001) and DA ratio (DAR, p = 0.004), while there were no significant differences in the means of pressure-derived parameters of ORA between groups. Multiple regression analysis showed all parameters of Corvis ST have significant relationships with level of myopia (SE, AXL, Mean KR), except AL1 and AL2. Significant biomechanical parameters showed progressive reduction in corneal stiffness with increasing myopia (either with greater negative SE or greater AXL), independent of IOP and CCT. Also, corneal hysteresis (CH) or ability to dissipate energy from the ORA decreased with increasing level of myopia.Conclusions: Dynamic corneal response assessed by Corvis ST shows evidence of biomechanical changes consistent with decreasing stiffness with increasing levels of myopia in multiple parameters. The strongest correlations were with highest concavity parameters where the sclera influence is maximal.

scholarly journals Corneal Biomechanical Assessment Using Corneal Visualization Scheimpflug Technology in Keratoconic and Normal Eyes

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lei Tian ◽  
Yi-Fei Huang ◽  
Li-Qiang Wang ◽  
Hua Bai ◽  
Qun Wang ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Corneal Thickness ◽  
Area Under The Curve ◽  
Biomechanical Properties ◽  
Corvis St ◽  
Biomechanical Assessment ◽  
Deformation Amplitude ◽  
Biomechanical Parameters ◽  
And Control ◽  
Corneal Biomechanical Properties

Purpose. To compare the corneal biomechanical properties of keratoconic patients and age-matched controls using corneal visualization Scheimpflug technology (Corvis ST).Methods. Sixty keratoconic eyes from 47 keratoconus patients and 60 normal eyes from 60 controls were enrolled in this prospective study. Tomography and biomechanical parameters of all eyes were obtained with the Pentacam and Corvis ST, respectively. Intraocular pressure was measured using a Goldmann applanation tonometer.Results.The tomography and biomechanical parameters of the keratoconic corneas were significantly different from those of the normal corneas except for the anterior chamber angle, first applanation length, the highest concavity time, and peak distance. The deformation amplitude was the best predictive parameter (area under the curve: 0.882), with a sensitivity of 81.7%, although there was a significant overlap between keratoconic and normal corneas that ranged from 1.0 to 1.4 mm. In both the keratoconus and control groups, the deformation amplitude was negatively correlated with intraocular pressure, central corneal thickness, and corneal volume at 3 and 5 mm.Conclusions. Corvis ST offers an alternative method for measuring corneal biomechanical properties. The possibility of classifying keratoconus based on deformation amplitude deserves clinical attention.

scholarly journals Relationship among Corneal Biomechanics, Anterior Segment Parameters, and Geometric Corneal Parameters

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Sadık Görkem Çevik ◽  
Sertaç Argun Kıvanç ◽  
Berna Akova-Budak ◽  
Mediha Tok-Çevik
Keyword(s):  
Corneal Thickness ◽  
Anterior Segment ◽  
Biomechanical Properties ◽  
Negative Association ◽  
Corneal Resistance Factor ◽  
Multivariate Models ◽  
Corrected Visual Acuity ◽  
Biomechanical Parameters ◽  
Anterior Segment Parameters ◽  
The Relationship

Purpose. To investigate the relationship between corneal biomechanical parameters, anterior segment parameters, and geometric corneal parameters in a healthy Caucasian group. Methods. This retrospective study included the healthy eyes with best corrected visual acuity of at least 20/40 of 122 Caucasian subjects. The anterior segment parameters and geometric corneal parameters such as corneal volume, central corneal thickness, horizontal and vertical corneal radii, anterior and posterior steep, and flat keratometric values were measured with a Scheimpflug camera. The biomechanical properties were measured with Ocular Response Analyzer. Results. One hundred and twenty-two healthy Caucasian subjects (67 males, 55 females) with a mean age of 45.32±20.23 were enrolled. Both corneal hysteresis and corneal resistance factor were positively correlated with CCT (r=0.529, p<0.001; r=0.638, p<0.001) and CV (r=0.635, p<0.001; r=0.579, p<0.001) and negatively correlated with age (r=-0.373, p<0.001; r=-0.249, p<0.001). Both in age-gender and multivariate models, CH and CRF had statistically significant negative association with the posterior steep K value. Conclusions. CH and CRF are negatively correlated with posterior steep and average posterior K values.

scholarly journals In VivoCorneal Biomechanical Properties with Corneal Visualization Scheimpflug Technology in Chinese Population

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Wu ◽  
Lei Tian ◽  
Yi-fei Huang
Keyword(s):  
Linear Regression ◽  
Healthy Subjects ◽  
Chinese Population ◽  
Regression Models ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Biomechanical Properties ◽  
Linear Regression Models ◽  
Corneal Volume ◽  
Biomechanical Parameters

Purpose. To determine the repeatability of recalculated corneal visualization Scheimpflug technology (CorVis ST) parameters and to study the variation of biomechanical properties and their association with demographic and ocular characteristics.Methods. A total of 783 healthy subjects were included in this study. Comprehensive ophthalmological examinations were conducted. The repeatability of the recalculated biomechanical parameters with 90 subjects was assessed by the coefficient of variation (CV) and intraclass correlation coefficient (ICC). Univariate and multivariate linear regression models were used to identify demographic and ocular factors.Results. The repeatability of the central corneal thickness (CCT), deformation amplitude (DA), and first/second applanation time (A1/A2-time) exhibited excellent repeatability (CV%≤3.312% and ICC≥0.929 for all measurements). The velocity in/out(Vin/out), highest concavity- (HC-) radius, peak distance (PD), and DA showed a normal distribution. Univariate linear regression showed a statistically significant correlation betweenVin,Vout, DA, PD, and HC-radius and IOP, CCT, and corneal volume, respectively. Multivariate analysis showed that IOP and CCT were negatively correlated withVin, DA, and PD, while there was a positive correlation betweenVoutand HC-radius.Conclusion. The ICCs of the recalculated parameters, CCT, DA, A1-time, and A2-time, exhibited excellent repeatability. IOP, CCT, and corneal volume significantly influenced the biomechanical properties of the eye.

scholarly journals Assessment of Corneal Biomechanical Properties and Intraocular Pressure in Myopic Spanish Healthy Population

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
María A. del Buey ◽  
Laura Lavilla ◽  
Francisco J. Ascaso ◽  
Elena Lanchares ◽  
Valentín Huerva ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
High Myopia ◽  
Biomechanical Properties ◽  
Control Group ◽  
Healthy Population ◽  
Iop Measurement ◽  
Group 3 ◽  
Biomechanical Parameters ◽  
Group 2 ◽  
The Relationship

Purpose. To examine biomechanical parameters of the cornea in myopic eyes and their relationship with the degree of myopia in a western healthy population.Methods. Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOP), and corneal compensated IOP (IOPcc) were measured using the ocular response analyzer (ORA) in 312 eyes of 177 Spanish subjects aged between 20 and 56 years. Refraction was expressed as spherical equivalent (SE), which ranged from 0 to −16.50 diopters (D) (mean:−3.88±2.90 D). Subjects were divided into four groups according to their refractive status: group 1 or control group: emmetropia (-0.50≤SE<0.50); group 2: low myopia (-0.75≤SE<3.00 D); group 3: moderate myopia (-3.00≤SE≤-6.00 D); and group 3: high myopia (SE greater than −6.00 D). We analyzed the relationship between corneal biomechanics measured with ORA and SE.Results. CH in the emmetropia, low myopia, moderate myopia, and high myopia groups was11.13±0.98,11.49±1.25,10.52±1.54, and10.35±1.33 mmHg, respectively. CH in the highly myopic group was significantly lower than that in the emmetropic group (P=0.07) and low myopic group (P=0.035); however, there were no differences with the moderate myopic group (P=0.872). There were no statistically significant differences regarding IOP among the four groups (P>0.05); nevertheless, IOPcc was significantly higher in the moderately myopic (15.47±2.47 mmHg) and highly myopic (16.14±2.59 mmHg) groups than in the emmetropia (15.15±2.06 mmHg) and low myopia groups (14.53±2.37 mmHg). No correlation between age and the measured parameters was found. CH and IOPcc were weakly but significantly correlated with SE (r=0.171,P=0.002andr=-0.131,P=0.021, resp.).Conclusions. Present study showed only a very weak, but significant, correlation between CH and refractive error, with CH being lower in both moderately and highly myopic eyes than that in the emmetropic and low myopic eyes. These changes in biomechanical properties of the cornea may have an impact on IOP measurement, increasing the risk of glaucoma.

scholarly journals The Study of Ocular Parameters in Low to Moderate Myopic Chinese Children Age Between Eight to Eighteen-Year-Old

2021 ◽  
Author(s):  
Zhengxuan Li ◽  
Lu Sun ◽  
Hongxin Song
Keyword(s):  
Retrospective Study ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Corneal Endothelial Cell ◽  
Spherical Equivalent ◽  
Corneal Endothelial Cell Density ◽  
The Mean ◽  
Beijing China ◽  
Corneal Diameter

Abstract Purpose: The primary aim of this study was to analyze the distribution of ocular parameters of children aged from eight to eighteen-year-old with low to moderate myopia as well as offer useful information for the design and clinical fitting of ortho-k lens in China.Methods: In this retrospective study, we collected data of 300 subjects (600 eyes) age between eight to eighteen-year-old from the myopic control outpatient clinic at Beijing Tongren Hospital, Beijing, China. The spherical equivalent (SE), axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), corneal endothelial cell density (CECD)，corneal diameter (CD), simulated K (Sim K) were collected from all the subjects and analyzed. Results: The mean of SE for all subjects was -3.12 ± 1.21D, the median was -3.16D. The mean of AL for all subjects was 24.72 ± 0.83 mm, the median was 24.72 mm. The mean of CCT for all subjects was 537.8 ± 29.82 μm, the median was 538.17 μm. The mean of CECD for all subjects was 3340.3 ± 352.6 cells/mm2, the median was 3357.77 cells/mm2. The mean of ACD for all subjects was 3.71 ± 0.21 mm, the median was 3.69 mm. The mean of CD for all subjects was 12.15 ± 1.67 mm, the median was 12.05 mm. The mean of flat K was 42.80 ± 1.29, the median was 42.81. The mean of steep K was 43.76 ± 1.37, the median was 43.76.Conclusions: This study provided the distribution of ocular parameters to offer useful information for diagnosis of many eye conditions. Meanwhile, the distribution of ocular parameters of children aged from eight to eighteen-year-old with low to moderate myopia is beneficial to make the application of overnight orthokeratology lens more appropriate and effective.

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