Ocular biomechanical measurements on post-keratoplasty corneas using a Scheimpflug-based noncontact device

Módis, László; Hassan, Ziad; Szalai, Eszter; Flaskó, Zsuzsanna; Berta, András; Németh, Gábor

doi:10.18240/ijo.2016.02.09

Cited by 3 publications

(2 citation statements)

References 20 publications

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“…Corvis ST monitors corneal deformation using an ultra-high-speed Scheimpflug camera with UV-free 455 nm light and provides a set of corneal deformation parameters. Previous studies evaluating corneal biomechanics in post-keratoplasty eyes showed that the deformation amplitude (DA) of transplanted cornea was significantly higher than normal eyes, while the radius at the highest concavity (RHC) was significantly smaller than normal eyes 15,16. This might suggest that corneal transplantation tended to weaken the corneal integrity.…”

Section: Discussionmentioning

confidence: 97%

<p>Factors predicting change in corneal astigmatism following suture removal in post-penetrating keratoplasty patients</p>

Satitpitakul¹,

Uramphorn²,

Kasetsuwan³

2019

OPTH

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PurposeTo identify factors predicting corneal astigmatic change following suture removal in post-penetrating keratoplasty patients.Patients and methodsThis cross-sectional study included the data of 33 events of corneal suture removal from 27 post-penetrating keratoplasty patients. Sutures were removed from the steep axis of transplanted cornea with 16 interrupted corneal sutures. Corneal astigmatism was measured before and after suture removal using ORBSCAN II. Patients’ demographic data and corneal biomechanics parameters obtaining from the Corvis ST were recorded. The changes in corneal astigmatism were calculated using vector analysis. The correlation between changes in corneal astigmatism and the potential factors was evaluated using Spearman’s correlation coefficient and linear regression model.ResultsThe mean corneal astigmatism before and after suture removal was 7.1±3.7 diopters (D) and 5.5±3.2D, respectively. The mean astigmatic change was 7.0±6.3D (range, 0.3–30.8D) by vector analysis at 9.7±5.5 weeks after suture removal. Change in corneal astigmatism was significantly correlated with pre-suture removal astigmatism (Rs=0.47, P=0.01). There was no correlation between the donor-recipient trephine diameter difference, the duration from corneal transplantation to suture removal, the number of removed sutures with the change in corneal astigmatism, and corneal biomechanics parameters (P>0.05). Linear regression is given by the following equation: astigmatic change (D)=1.05x pre-suture removal astigmatism (D) - 0.43.ConclusionThe astigmatic change after corneal suture removal in post-keratoplasty patients was significantly correlated with pre-suture removal astigmatism. These findings will permit a validated approach for reducing corneal astigmatism in post-keratoplasty patients.

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Section: Discussionmentioning

confidence: 97%

<p>Factors predicting change in corneal astigmatism following suture removal in post-penetrating keratoplasty patients</p>

Satitpitakul¹,

Uramphorn²,

Kasetsuwan³

2019

OPTH

View full text Add to dashboard Cite

show abstract

“…There is a relationship between alterations in corneal biomechanics and different factors and ocular parameters such as age [ 12 , 13 ], diabetes [ 14 ], caffeine intake [ 15 ], hormonal changes [ 16 ], level of hydration and fasting [ 17 ], exposure to ultraviolet radiation [ 18 ], intraocular pressure (IOP) [ 13 , 19 ], refractive error [ 20 ], axial length [ 13 ], corneal central thickness and corneal curvature [ 13 ], ocular surgery [ 9 , 10 , 21 ] or orthokeratology [ 22 , 23 ] among others.…”

Section: Introductionmentioning

confidence: 99%

The short-term effects of wearing swimming goggles on corneal biomechanics

et al. 2022

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Purpose This study aimed to assess the impact of wearing swimming goggles (SG) on corneal biomechanics. Methods Corneal deformation response, central corneal thickness (CCT), intraocular pressure (IOP) and biomechanically corrected intraocular pressure (bIOP) were measured with the Corvis system (Oculus Optikgeräte GmbH, Wetzlar, Germany) in thirty-one healthy young adults while wearing a drilled SG. All measurements were obtained before, at 30 s, 2 min, 3.5 min and 5 min of wearing SG, just after SG removal and after 2 min of SG removal. Results The corneal biomechanics is sensitive to SG wear, observing lower corneal deformability during SG use. Specifically, wearing SG caused an increase in the time and length of the first applanation and radius curvature at the highest concavity, as well as a decrease and in the velocity of the first applanation and time and deformation amplitude of the second applanation (p < 0.001 in all cases). After SG removal, corneal biomechanical parameters showed a rebound-effect, obtaining a higher corneal deformability in comparison with baseline reading (p-corrected < 0.05 in all cases). Additionally, IOP and bIOP significantly increased while wearing SG (p < 0.001 in both cases), whereas CCT remained stable (p = 0.850). Conclusions Wearing SG modifies the biomechanical properties of the cornea, with reduced corneal deformability during SG wear. The outcomes of this study should be taken into consideration when making clinical decisions in subjects at high risk of developing corneal ectasias or glaucoma, as well as in the post-surgical management of these ocular conditions.

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The Use of a Dynamic Scheimpflug Analyzer to Measure Changes of Post-keratoplasty Corneal Biomechanical Properties

Park

Jun

Seo³

et al. 2020

J Korean Ophthalmol Soc

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Purpose: To evaluate the biomechanical properties of corneas using a dynamic Scheimpflug analyzer (Corvis ST) after penetrating keratoplasty (PKP) and Descemet's membrane stripping keratoplasty (DSEK). Methods: The medical records of 11 eyes that had undergone PKP (PKP group) and 11 eyes that had undergone DSEK (DSEK group) from March 2017 to March 2018 and the results were compared with 20 eyes of the control group. All patients' corneal biomechanical properties, including a deformation amplitude ratio of 2.0 mm (DA ratio 2.0 mm), integrated inverse radius (IntInvRad), stiffness parameter at first applanation (SP-A1), and Ambrosio relational thickness through the horizon meridian (ARTh) were measured and compared with those of the normal control group. In addition, biomechanically corrected intraocular pressure (bIOP) measured by the Corvis ST was compared with intraocular pressure measured by a Tono-Pen Applanation Tonometer (IOP-Tono-Pen). Results: In the PKP group, the biomechanical properties using the Corvis ST showed a significantly lower DA ratio 2.0 mm, SP-A1, ARTh, and IntInvRad, compared with those of the control group. However, in the DSEK group, only ARTh was significantly lower than that of the control group. Conclusions: Corvis ST can be used to measure the change of corneal biomechanical properties after corneal transplantation.

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Ocular biomechanical measurements on post-keratoplasty corneas using a Scheimpflug-based noncontact device

Abstract: The ocular biomechanics remain stable after penetrating keratoplasty according to the CorVis ST measurements. Only two from the ten device-specific parameters have importance in the follow-up period after penetrating keratoplasty.

Cited by 3 publications

References 20 publications

<p>Factors predicting change in corneal astigmatism following suture removal in post-penetrating keratoplasty patients</p>

<p>Factors predicting change in corneal astigmatism following suture removal in post-penetrating keratoplasty patients</p>

The short-term effects of wearing swimming goggles on corneal biomechanics

The Use of a Dynamic Scheimpflug Analyzer to Measure Changes of Post-keratoplasty Corneal Biomechanical Properties

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