scholarly journals Corneal Biomechanics Determination in Healthy Myopic Subjects

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Kunliang Qiu ◽  
Xuehui Lu ◽  
Riping Zhang ◽  
Geng Wang ◽  
Mingzhi Zhang
Keyword(s):  
Regression Analysis ◽  
Intraocular Pressure ◽  
Axial Length ◽  
Multivariate Regression ◽  
Biomechanical Properties ◽  
Corneal Biomechanics ◽  
Ocular Response Analyzer ◽  
Corneal Curvature ◽  
Factors Associated ◽  
Corneal Biomechanical Properties

Purpose. To determine the corneal biomechanical properties by using the Ocular Response Analyzer™and to investigate potential factors associated with the corneal biomechanics in healthy myopic subjects.Methods. 135 eyes from 135 healthy myopic subjects were included in this cross-sectional observational study. Cornea hysteresis (CH), corneal resistance factor (CRF), cornea-compensated intraocular pressure (IOPcc), and Goldmann-correlated intraocular pressure (IOPg) were determined with the Reichert Ocular Response Analyzer (ORA). Univariate and multivariate regression analyses were performed to investigate factors associated with corneal biomechanics.Results. The mean CH and CRF were9.82±1.34 mmHg and9.64±1.57 mmHg, respectively. In univariate regression analysis, CH was significantly correlated with axial length, refraction, central corneal thickness (CCT), and IOPg (r=-0.27, 0.23, 0.45, and 0.21, resp.; all withp≤0.015), but not with corneal curvature or age; CRF was significantly correlated with CCT and IOPg (r=0.52and 0.70, resp.; all withp<0.001), but not with axial length/refraction, corneal curvature, or age. In multivariate regression analysis, axial length, IOPcc, and CCT were found to be independently associated with CH, while CCT and IOPg were associated with CRF.Conclusions. Both CH and CRF were positively correlated with CCT. Lower CH but not CRF was associated with increasing degree of myopia. Evaluation of corneal biomechanical properties should take CCT and myopic status into consideration.

scholarly journals Association of Corneal Biomechanics Properties with Myopia in a Child and a Parent Cohort: Hong Kong Children Eye Study

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2357
Author(s):  
Shu-Min Tang ◽  
Xiu-Juan Zhang ◽  
Marco Yu ◽  
Yu-Meng Wang ◽  
Carol Y. Cheung ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Population Based ◽  
Older Age ◽  
Corneal Biomechanics ◽  
Spherical Equivalent ◽  
Corneal Curvature ◽  
Population Based Study ◽  
Factors Associated ◽  
Deformation Amplitude ◽  
Corneal Deformation

Associations between corneal biomechanics, axial elongation and myopia are important but previous results are conflicting. Our population-based study aimed to investigate factors associated with corneal biomechanics, and their relationships with myopia in children and adults. Data from 3643 children and 1994 parents showed that children had smaller deformation amplitudes (DA) than parents (p < 0.001). A larger DA was significantly associated with elongated axial length (AL; children: ß = 0.011; adults: ß = 0.0013), higher corneal curvature (children: ß = 0.0086; adults: ß = 0.0096), older age (children: ß = 0.010; adults: ß = 0.0013), and lower intraocular pressure (IOP; children: ß = −0.029; adults: ß = −0.031) in both cohorts. The coefficient of age for DA in children was larger than in adults (p < 0.001), indicating that the DA change with age in children is faster than in adults. DA was significantly associated with spherical equivalent (p < 0.001) resulting from its correlation with AL and corneal curvature. In conclusion, the cornea is more deformable in adults than in children, whereas corneal deformation amplitude increases faster with age in children than that in adults, along with AL elongation. Longer AL, steeper corneal curvature, older age and smaller IOP correspond to a more deformable cornea. The association between corneal deformation amplitude and refraction was mediated via AL and corneal curvature.

scholarly journals Evaluation of Corneal Biomechanical Properties Modification after Small Incision Lenticule Extraction Using Scheimpflug-Based Noncontact Tonometer

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Leonardo Mastropasqua ◽  
Roberta Calienno ◽  
Manuela Lanzini ◽  
Martina Colasante ◽  
Alessandra Mastropasqua ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Corneal Biomechanics ◽  
Small Incision Lenticule Extraction ◽  
Small Incision ◽  
Lenticule Extraction ◽  
Noncontact Tonometer ◽  
Corneal Biomechanical Properties

Purpose.To quantify the effect of small incision lenticule extraction (SMILE) on the corneal biomechanics using Scheimpflug noncontact tonometer (Corvis ST).Methods.Twenty eyes of twenty patients, evaluated as eligible for surgery, with high myopia and/or moderate myopic astigmatism, underwent small incision lenticule extraction (SMILE). All patients underwent Corvis ST preoperatively and postoperatively after 1 week, and 1 and 3 months to observe alterations of corneal biomechanical properties. The main outcome measures were Deformation Amplitude, 1st-AT, and 2nd-AT. The relationship between the amount of stroma removed and the percentage variation of the measured parameters from baseline was evaluated with generalized linear model from each time point. For completeness also intraocular pressure (IOP), central corneal thickness (CCT), and their variations after surgery were evaluated.Results.The ratio between the amount of removed refractive error and, respectively, changes of Deformation Amplitude, 1st-AT, and 2nd-AT were significantly modified at the 1st week after surgery(P=0.005; P=0.001; P=0.024). At 1 and 3 months these values did not show statistically significant alterations. Intraocular pressure and central corneal thickness showed statistically significant changes during follow-up.Conclusions.No significant modifications in biomechanical properties were observed after SMILE so this procedure could induce only minimal transient alterations of corneal biomechanics.

Factors affecting changes in the intraocular pressure after phacoemulsification surgery

2020 ◽  
Vol 1 (3) ◽  
pp. 166-172
Author(s):  
Rita Dhamankar ◽  
◽  
Suhas S Haldipurkar ◽  
Tanvi Haldipurkar ◽  
Vijay Shetty ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Axial Length ◽  
Anterior Chamber Depth ◽  
The Other ◽  
Factors Affecting ◽  
Factors Associated ◽  
Post Surgery ◽  
Unit Increase ◽  
The Mean

AIM: To assess the changes in anterior chamber parameters and examine the factors associated with changes in the intraocular pressure (IOP) in individuals who have undergone phacoemulsification surgery. METHODS: It is a longitudinal analysis of secondary clinical data collected from 105 non-glaucomatous eyes (82 patients) undergoing a cataract surgery. We studied the association between anterior chamber parameters, grade of cataract, demographics, and changes in the IOP over a period of three weeks. We also evaluated the association between the pressure-depth (PD) ratio and changes in the IOP during this time. RESULTS: The mean age (SD) of the 82 patients was 60.1±7.8y. The mean±standard deviation (SD) IOP was 15.06±3.36 mm Hg pre-operatively; it increased to 15.75±4.21 mm Hg on day one (P=0.20). In the multifactorial models, the mean IOP was -1.715 (95%CI: -2.795, -0.636) mm Hg on day 21±5 compared with the pre-operative values. The anterior chamber depth (ACD), axial length, age, sex, and grade of cataract were not significantly associated with changes in the IOP. Each unit increase in the PD ratio was associated with an increase in the mean IOP by 1.289 mm Hg (95%CI: 0.906, 1.671). After adjusting for pre-operative PD ratio, none of the other variables (ACD, axial length, temporal angle) were significantly associated with changes in mean IOP. CONCLUSION: The PD ratio was the single most important factor associated with the changes in post-operative IOP over three weeks post-surgery.

Evaluation of Biomechanically Corrected Intraocular Pressure Measurements in Keratoconus and Forme Fruste Keratoconus

2020 ◽  
Vol 63 (6) ◽  
pp. 541-549
Author(s):  
Tomoya Nishida ◽  
Takashi Kojima ◽  
Takahiro Kataoka ◽  
Naoki Isogai ◽  
Yoko Yoshida ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Biomechanical Properties ◽  
Control Group ◽  
Pressure Measurements ◽  
Altman Plot ◽  
Significant Difference ◽  
The Difference ◽  
The Right ◽  
Corneal Biomechanical Properties ◽  
Forme Fruste Keratoconus

<b><i>Introduction:</i></b> Although biomechanically corrected intraocular pressure (bIOP) is available, the effectiveness of intraocular pressure (IOP) correction in keratoconus and forme fruste keratoconus (FFK) eyes has not been investigated. <b><i>Objective:</i></b> Evaluation of bIOP measurements in eyes with keratoconus and FFK. <b><i>Methods:</i></b> Forty-two eyes in 21 patients with keratoconus in one eye and FFK in the fellow eye were examined (KC/FFK group; mean age 24.62 ± 8.6 years; 16 males and 5 females). The control group consisted of 62 eyes in 31 unaffected subjects (mean age 26.26 ± 3.64 years; 15 males and 16 females). The bIOP was determined using a Scheimpflug-based tonometer (Corvis Scheimpflug Technology [Corvis ST®]) after measuring the IOP with a conventional non-contact tonometer (NIOP). The agreement between NIOP and bIOP values was examined using the Bland-Altman plot. The difference between NIOP and bIOP (bIOP correction amount) was compared between keratoconus and FFK eyes. <b><i>Results:</i></b> In the control group, there were no significant differences between right and left eyes in both NIOP and bIOP values (<i>p</i> = 0.975 and <i>p</i> = 0.224, respectively). In the KC/FFK group, NIOP values were significantly lower in the keratoconus eyes (9.93 ± 1.96 mm Hg) than in the FFK eyes (12.23 ± 3.03 mm Hg; <i>p</i> = 0.0003). There was no significant difference in bIOP values between the right and left eyes of the KC/FFK group (<i>p</i> = 0.168). The bIOP correction amount was significantly increased in keratoconus eyes (3.58 ± 2.12 mm Hg) compared to in FFK eyes (1.80 ± 3.32 mm Hg; <i>p</i> = 0.011). <b><i>Conclusions:</i></b> For eyes with keratoconus and FFK, the bIOP method is effective to adjust IOP measurements based on corneal biomechanical properties.

Patient-Related Risk Factors Associated With Surgical Site Complications After Elective Hand Surgery

Hand ◽  
2020 ◽  
pp. 155894472094426
Author(s):  
Tyler Youngman ◽  
Michael Del Core ◽  
Timothy Benage ◽  
Daniel Koehler ◽  
Douglas Sammer ◽  
...  
Keyword(s):  
Risk Factors ◽  
Regression Analysis ◽  
Surgical Complications ◽  
Multivariate Regression ◽  
Univariate Analysis ◽  
Hand Surgery ◽  
Multivariate Regression Analysis ◽  
Class Iii ◽  
Factors Associated ◽  
Surgical Site Complications

Background: The purpose of this study was to identify independent risk factors associated with an increased rate of surgical site complications after elective hand surgery. Methods: This study is a retrospective review of all patients who underwent elective hand, wrist, forearm, and elbow surgery over a 10-year period at a single institution. Electronic medical records were reviewed, and information regarding patient demographics, past medical and social history, perioperative laboratory values, procedures performed, and surgical complications was collected. Surgical site complications included surgical site infections, seromas or hematomas, and delayed wound healing or wound dehiscence. A univariate analysis was then performed to identify potential risk factors, which were then included in a multivariate regression analysis. Results: A total of 3261 patients who underwent elective hand surgery and met the above inclusion and exclusion criteria were included in this study. The mean age was 57 years, with 65% female and 35% male patients. The overall surgical complication rate was 2.2%. Univariate analysis of patient factors identified male sex; number of procedures >1; history of drug, alcohol, or smoking use; American Society of Anesthesiologists (ASA) class III and IV; and serum albumin <3.5 mg/dL to be significantly associated with complications. However, multivariate regression analysis identified that only ASA class III and IV (odds ratio = 3.27) was significantly associated with surgical complications. Conclusions: Patients classified as ASA class III or IV were identified to be at a significantly increased risk of complications following elective hand surgery. Health factors which triage patients into these 2 groups may represent potentially modifiable factors to mitigate perioperative risk in the elective hand surgery population.

scholarly journals Role of corneal biomechanical properties in predicting of speed of myopic progression in children wearing orthokeratology lenses or single-vision spectacles

2018 ◽  
Vol 3 (1) ◽  
pp. e000204 ◽  
Author(s):  
Kin Wan ◽  
Sin Wan Cheung ◽  
James S Wolffsohn ◽  
Janis B Orr ◽  
Pauline Cho
Keyword(s):  
Axial Length ◽  
Corneal Thickness ◽  
Significant Negative Correlation ◽  
Biomechanical Properties ◽  
Corneal Hysteresis ◽  
Axial Elongation ◽  
Single Vision ◽  
Length Data ◽  
Corneal Biomechanical Properties

ObjectiveTo determine the characteristics of children who were likely to progress rapidly and gain the greatest benefit from orthokeratology (ortho-k) treatment.Methods and analysisThe files of 113 children who participated in two myopia control studies and wore either ortho-k lenses (n=62) or single-vision spectacles (SVS) (n=51) were reviewed. Baseline cycloplegic subjective refraction, central corneal thickness, axial length, keratometry, intraocular pressure, corneal biomechanical properties and 24-month axial length data were retrieved and analysed.ResultsMultivariate analysis showed that there was significant negative correlation between axial elongation and baseline age and corneal hysteresis (p<0.05) in the SVS group. In the ortho-k group, only baseline age was significantly and negatively associated with axial elongation (p<0.01).ConclusionCorneal biomechanical properties and baseline age can predict the rate of axial elongation in myopic children. It may be beneficial for younger myopic children with low corneal hysteresis to commence ortho-k treatment as early as possible.

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