Evaluation of Corneal Deformation Parameters Provided by the Corvis ST Tonometer After Trabeculectomy

Zong, Yuan; Wu, Na; Fu, Zhi-xuan; Kong, Xiangmei

doi:10.1097/ijg.0000000000000590

Cited by 8 publications

(3 citation statements)

References 24 publications

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“…For example, the optimal model to describe A2 Velocity included IOP-GAT; A2 Velocity is correlated to IOP-G [ 14 , 25 ] largely because corneal movement during its returning phase is faster when IOP-G is high [ 14 , 25 ]. Nonetheless, eye status (coefficient = -0.023 for 3m-post operation) was also included in the model to explain A2 Velocity, which suggests A2 velocity is faster after cataract surgery despite a decrease in IOP-G. Interestingly, in eyes with trabeculectomy [ 28 ] as well as eyes with cataract surgery [ 24 ], A2 velocity quickens after surgery. The first applanation may reflect collagen fiber elasticity, whereas the second applanation may be related to corneal viscoelasticity [ 28 ].…”

Section: Discussionmentioning

confidence: 99%

“…Nonetheless, eye status (coefficient = -0.023 for 3m-post operation) was also included in the model to explain A2 Velocity, which suggests A2 velocity is faster after cataract surgery despite a decrease in IOP-G. Interestingly, in eyes with trabeculectomy [ 28 ] as well as eyes with cataract surgery [ 24 ], A2 velocity quickens after surgery. The first applanation may reflect collagen fiber elasticity, whereas the second applanation may be related to corneal viscoelasticity [ 28 ]. Therefore, we suggest that eye surgery with direct invasion of the anterior chamber may cause viscoelasticity changes.…”

Section: Discussionmentioning

confidence: 99%

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Cataract surgery causes biomechanical alterations to the eye detectable by Corvis ST tonometry

Kato¹,

Nakakura²,

Asaoka

et al. 2017

PLoS ONE

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PurposeModern cataract surgery is generally considered to bring about modest and sustained intraocular pressure (IOP) reduction. However, the pathophysiological mechanism for this remains unclear. Moreover, a change in ocular biomechanical properties after surgery can affect the measurement of IOP. The aim of the study is to investigate ocular biomechanics, before and following cataract surgery, using Corvis ST tonometry (CST).Patients and methodsFifty-nine eyes of 59 patients with cataract were analyzed. IOP with Goldmann applanation tonometry (IOP-G), axial length, corneal curvature and CST parameters were measured before cataract surgery and, up to 3 months, following surgery. Since CST parameters are closely related to IOP-G, linear modeling was carried out to investigate whether there was a change in CST measurements following cataract surgery, adjusted for a change in IOP-G.ResultsIOP-G significantly decreased after surgery (mean±standard deviation: 11.8±3.1 mmHg) compared to pre-surgery (15.2±4.3 mmHg, P<0.001). Peak distance (the distance between the two surrounding peaks of the cornea at the highest concavity), maximum deformation amplitude (the movement of the corneal apex from the start of deformation to the highest concavity) and A1/A2 velocity (the corneal velocity during inward or outward movement) significantly increased after cataract surgery (P<0.05) while radius (the central curvature radius at the highest concavity) was significantly smaller following cataract surgery (P<0.05). Linear modeling supported many of these findings, suggesting that peak distance, maximum deformation amplitude and A2 velocity were increased, whereas A2 deformation amplitude and highest concavity time were decreased (after adjustment for IOP change), following cataract surgery.ConclusionCorneal biomechanical properties, as measured with CST, were observed to change significantly following cataract surgery.Trial registrationJapan Clinical Trials Registry UMIN000014370

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Cataract surgery causes biomechanical alterations to the eye detectable by Corvis ST tonometry

Kato¹,

Nakakura²,

Asaoka

et al. 2017

PLoS ONE

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“…A previous study reported that A1V was significantly higher in eyes treated with prostaglandin analogues (PGAs) than in those treated without PGAs [ 2 ]. Another study reported that A1V increased significantly even after the first week of antiglaucoma surgery [ 20 ]. In some studies on long-term treatment with topical medications, DAHC increased markedly after 2 years, while PDHC increased slightly [ 2 , 8 ].…”

Section: Discussionmentioning

confidence: 99%

Correlations among Corneal Biomechanical Parameters, Stiffness, and Thickness Measured Using Corvis ST and Pentacam in Patients with Ocular Hypertension

Liu

Pang

Liu

et al. 2022

Journal of Ophthalmology

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Background. To preliminary explore the correlations among corneal biomechanical parameters, stiffness, and thickness in patients with ocular hypertension (OHT) before and after treatment with topical antiglaucoma medications. Methods. This was a retrospective study that included 35 eyes with newly diagnosed OHT. Axial length (AL), apical corneal thickness, and minimum corneal thickness were measured using Pentacam. The lengths, velocities, and times of the first and second corneal applanations (A1L, A1V, A1T, A2L, A2V, and A2T, respectively); the highest concavity radius; highest concavity peak distance (PDHC); highest concavity deformation amplitude (DAHC); highest concavity time (HCT); pachymetry (PACH); stress-strain index (SSI); stiffness parameter-A1 (SP-A1); deformation amplitude ratio (DA ratio); integrated radius (IR); Ambrosio’s relational thickness horizontal (ARTh); corneal biomechanical index; noncorrected intraocular pressure (IOPnct); and biomechanically corrected IOP (bIOP) values were measured using the corneal visualization Scheimpflug technology (Corvis ST/CST). Results. After 5 weeks of treatment, Goldman applanation tonometer-IOP, IOPnct, bIOP, PACH, A1T, A2V, SSI, SP-A1, and ARTh decreased, but A1V, A2T, PDHC, DAHC, DA ratio, and IR increased significantly (all p < 0.05 ). SP-A1 and A1T were positively associated with premedication IOP and IOP changes, whereas A1V, A2T, PDHC, and IR were negatively associated (all p < 0.05 ). DAHC and DA ratio had significantly negative correlations with IOP variations. PDHC was found to be positively correlated with AL ( p < 0.05 ). A positive relationship was noted between SP-A1 and HCT before medication ( p < 0.05 ). Conclusions. SP-A1 was significantly and consistently associated with IOP. HCT might be correlated with SP-A1. SP-A1 and CST parameters could serve as potential biomarkers for evaluating OHT treatment efficacy.

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Dynamischer Scheimpflug-Analyzer (Corvis ST) zur Bestimmung kornealer biomechanischer Parameter

et al. 2018

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Evaluation of Corneal Deformation Parameters Provided by the Corvis ST Tonometer After Trabeculectomy

Abstract: CST is a good choice for measuring IOP, especially when aiming for normalization of IOP after glaucoma surgery.

Cited by 8 publications

References 24 publications

Cataract surgery causes biomechanical alterations to the eye detectable by Corvis ST tonometry

Cataract surgery causes biomechanical alterations to the eye detectable by Corvis ST tonometry

Correlations among Corneal Biomechanical Parameters, Stiffness, and Thickness Measured Using Corvis ST and Pentacam in Patients with Ocular Hypertension

Dynamischer Scheimpflug-Analyzer (Corvis ST) zur Bestimmung kornealer biomechanischer Parameter

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