scholarly journals Applications of Scheimpflug Imaging in Glaucoma Management: Current and Potential Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Alexander T. Nguyen ◽  
Tiffany Liu ◽  
Ji Liu
Keyword(s):  
Intraocular Pressure ◽  
Image Reconstruction ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Three Dimensional ◽  
Biomechanical Properties ◽  
Scheimpflug Imaging ◽  
Potential Applications ◽  
Corneal Biomechanical Properties

Scheimpflug photography is the basis for a variety of imaging devices that are highly versatile. The applications of Scheimpflug imaging are wide in scope, spanning from evaluation of corneal ectasia to quantifying density in nuclear sclerotic cataracts. The potential uses for Scheimpflug-based devices are expanding and a number of them are relevant in glaucoma. In particular, they can provide three-dimensional image reconstruction of the anterior segment which includes assessment of the iridocorneal angle. Photographic analyses allow also for a noncontact method of estimating central corneal thickness (CCT) and intraocular pressure (IOP), as well as the study of various corneal biomechanical properties, which may be useful for stratifying glaucoma risk.

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.

Relationship between novel intraocular pressure measurement from Corvis ST and central corneal thickness and corneal hysteresis

2019 ◽  
Vol 104 (4) ◽  
pp. 563-568 ◽  
Author(s):  
Masato Matsuura ◽  
Hiroshi Murata ◽  
Yuri Fujino ◽  
Mieko Yanagisawa ◽  
Yoshitaka Nakao ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Linear Regression Analysis ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Applanation Tonometry ◽  
Corneal Hysteresis ◽  
Corneal Resistance Factor ◽  
Corvis St ◽  
The Relationship

AimsCorvis ST (CST) yields biomechanical corrected IOP (bIOP) which is purported to be less dependent on biomechanical properties. In our accompanied paper, it was suggested that the repeatability of bIOP is high. The purpose of the current study was to assess the relationship between intraocular pressure (IOP) measured with CST and central corneal thickness (CCT) and corneal hysteresis (CH), in comparison with IOP measured with Goldmann applanation tonometry (GAT) and the ocular response analyzer (ORA).MethodsA total of 141 eyes from 141 subjects (35 healthy eyes and 106 glaucomatous eyes) underwent IOP measurements with GAT, CST and ORA. The relationships between IOP measurements (ORA-IOPg, ORA-IOPcc, CST-bIOP and GAT IOP) and biomechanical properties (CCT, CH and corneal resistance factor (CRF)) were analysed using the linear regression analysis.ResultsIOPg, IOPcc and GAT IOP were significantly associated with CCT (p<0.001), whereas bIOP was not significantly associated with CCT (p=0.19). IOPg, bIOP and GAT IOP were significantly associated with CH (IOPg: p<0.001; bIOP: p<0.001; GAT IOP: p=0.0054), whereas IOPcc was not significantly associated with CH (p=0.18). All of IOP records were associated with CRF (p<0.001).ConclusionThe bIOP measurement from CST is independent from CCT, but dependent on CH and CRF.

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 Evaluation the Acute Effects of Hyperbaric Oxygen Therapy on Eye Anterior Segment Morphology and on İntraocular Pressure

2021 ◽  
Author(s):  
Fatih Akıncı ◽  
Abdullah Arslan ◽  
Muammer Özcimen
Keyword(s):  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Hyperbaric Oxygen ◽  
Hyperbaric Oxygen Therapy ◽  
Central Corneal Thickness ◽  
Oxygen Therapy ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Iridocorneal Angle

Abstract Purpose: In this study the acute effects of 1 session of hyperbaric oxygen therapy on eye anterior segment morphology and on intraocular pressure was evaluated.Materials and methods: 30 patients taking hyperbaric oxygen therapy for different indications were included in this prospective study. Only the right eye per patient was included in the study. The refractive errors were measured with autorefractometry, intraocular pressures were measured with pneumatic tonometry; anterior segment parameters pachymetry, keratometry, anterior chamber depth and iridocorneal angle values were measured with corneal topography prior to and 24 hours after 1 session of hyperbaric oxygen therapy.Results: In this study 30 eyes from a total of 30 patients were evaluated; 19 men (% 64) and 11 women (% 36). Median age was 44.33 ±16.12 (Age range 18-80 years). Mean intraocular pressure was 13.7 ±4,16 mmHg (milimetermercuries), mean central corneal thickness was 531.9 ±28.24 μm, mean anterior chamber depth was 3.30 ±0.375 mm, mean iridocorneal angle value was 35.3± 6.61 degrees before hyperbaric oxygen therapy. The mean intraocular pressure was 12.66±4,54 mmHg, mean central corneal thickness was 529.43± 26.68 μm, mean anterior chamber depth was 3.28±0.372 mm, mean iridocorneal angle value was 34.5±6.42 degrees after HBOT. A statistically significant decrease in these values were recorded. No statistically significant changes were found in spheric equivalent and keratometry values of the patients before and after HBOT.Conclusions: After one session of HBOT a decrease in intraocular pressure, central corneal thickness, anterior chamber depth and iridocorneal angles of patients were observed; keratometry and spheric equivalent values remained unchanged. More studies are needed in order to use the effects of HBOT on anterior segment morphology and on intraocular pressure for situations like glaucoma, corneal edema etc.

Ocular Response Analyser — a New Diagnostic Tool to Measure Corneal Biomechanical Properties and Intraocular Pressure

1970 ◽  
Vol 12 (3) ◽  
pp. 159-168
Author(s):  
Arulmozhi Varman ◽  
Muthuraman Chockalingam
Keyword(s):  
Intraocular Pressure ◽  
Diagnostic Tool ◽  
Pressure Measurement ◽  
Corneal Thickness ◽  
Biomechanical Properties ◽  
Ocular Diseases ◽  
Wide Range ◽  
Corneal Biomechanical Properties ◽  
Ocular Response Analyser

Corneal biomechanical properties have been known to influence the outcome of ocular measurements and procedures for a wide range of ocular diseases. The assessment of corneal biomechanical properties has been a challenge and, for this reason, measurement of the geographical parameters of the cornea, namely corneal thickness and topography, has formed the mainstay of understanding the basis of various ocular pathologies. A newly marketed instrument, the Reichert ocular response analyser has been developed to improve the accuracy of intraocular pressure measurement by uniquely measuring and integrating corneal biomechanical data into its intraocular pressure estimates.

scholarly journals Corneal biomechanical properties in myopic eyes evaluated via Scheimpflug imaging

2020 ◽  
Author(s):  
A-Yong Yu ◽  
Hui Shao ◽  
Anpeng Pan ◽  
Qinmei Wang ◽  
Zixu Huang ◽  
...  
Keyword(s):  
Axial Length ◽  
High Myopia ◽  
Anterior Segment ◽  
Biomechanical Properties ◽  
Corvis St ◽  
Negatively Associated ◽  
Scheimpflug Imaging ◽  
Biomechanical Parameters ◽  
Corneal Biomechanical Properties ◽  
Myopia Control

Abstract Background: To investigate the biomechanical properties of the cornea in myopic eyes using corneal visualization scheimpflug technology (Corvis ST). The relationships between the biomechanical properties of the cornea and the degree of myopia were also investigated.Methods: 265 eyes of 265 subjects were included. Based on spherical equivalent (SE) in diopters (D), participants were divided into four groups: low myopia/control (SE: -0.50 to -3.00D), moderate myopia (SE: -3.00 to -6.00D), high myopia (SE: -6.00 to -10.00D) and severe myopia (SE greater than -10.00D). Axial length (AL), anterior segment parameters, and corneal biomechanical properties were obtained with the Lenstar LS900, Pentacam HR and Corvis ST, respectively.Results: Mean (±SD) SE was -7.29±4.31D (range: -0.63 to -25.75D). Mean AL was 26.31±1.82mm (range: 21.87 to 31.94mm). Significant differences were detected within the four groups in terms of six corneal biomechanical parameters: deformation amplitude (DA), time from start until second applanation (A2-time), length of flattened cornea at the second applanation (A2-length), corneal velocity during the first and second applanation (A2-velocity), time from start to highest concavity (HC-time), and central curvature at highest concavity (HC radius). AL was positively associated with DA whereas negatively associated with A1-velocity and A2-length. SE was positively associated with A2-time, HC-time and A2-velocity, whereas negatively associated with DA. IOP was positively associated with four corneal biomechanical parameters and negatively associated with three parameters.Conclusions: Eyes with severe myopia showed greater DA, lesser A2 time, HC time, and faster A2-velocity compared to low to high myopia. This suggests the cornea becomes weaker and more deformable with elongation of axial length with corresponding increases in myopia. DA, A2-time and A2-velocity could be useful corneal biomechanical indicators in patients with myopia.

scholarly journals Central Corneal Thickness in Spectral-Domain OCT and Associations with Ocular and Systemic Parameters

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Alexander Karl-Georg Schuster ◽  
Joachim Ernst Fischer ◽  
Urs Vossmerbaeumer
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Cross Sectional Study ◽  
Ophthalmological Examination ◽  
Cross Sectional ◽  
Cardiovascular Parameters ◽  
Spectral Domain Oct ◽  
Sd Oct

Background. Optical coherence tomography (OCT) allows quantitative analysis of the anterior segment of the eye with a noncontact examination. The aim of this study is to analyze associations of central corneal thickness (CCT) as measured by OCT with ocular and systemic cardiovascular parameters.Methods. A cross-sectional study of 734 persons was performed in a working age population. Only healthy eyes were included. A comprehensive ophthalmological examination including refraction, noncontact tonometry, and imaging of the anterior segment by SD-OCT was performed. In parallel, a broad range of systemic cardiovascular parameters were measured. Associations were analyzed using a generalized estimating equations’ model.Results. CCT measurements showed a significant association with corneal curvature and intraocular pressure: a thinner CCT was associated with a flatter cornea and with lower intraocular pressure (p<0.001). Age was positively associated with CCT (p<0.001); all other cardiovascular parameters were not associated.Conclusion. A thinner cornea is associated with a flatter surface and with lower intraocular pressure readings, while there are no independent associations with refraction and systemic cardiovascular parameters. Our findings highlight the value of SD-OCT CCT measurements as a standard tool in anterior segment analysis.

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