Relationship between Corneal Biomechanical Properties and Optic Nerve Head Changes after Deep Sclerectomy

2017 ◽  
Vol 27 (5) ◽  
pp. 535-541 ◽  
Author(s):  
Laura Díez-Álvarez ◽  
Francisco J. Muñoz-Negrete ◽  
Pilar Casas-Llera ◽  
Noelia Oblanca ◽  
Victoria de Juan ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Open Angle Glaucoma ◽  
Biomechanical Properties ◽  
Resistance Factor ◽  
Corneal Hysteresis ◽  
Enhanced Depth Imaging ◽  
Deep Sclerectomy ◽  
Corneal Resistance Factor ◽  
Corneal Biomechanical Properties

Purpose To evaluate corneal biomechanical properties and optic nerve head (ONH) changes following deep sclerectomy (DS) and the relation to each other. Methods Forty-nine eyes with primary open-angle glaucoma that underwent DS were studied. Corneal biomechanical properties were assessed using the Ocular Response Analyzer and the ONH was evaluated by Spectralis optical coherence tomography with enhanced depth imaging technology before surgery and 3 months postoperatively. Changes in corneal hysteresis (CH), corneal resistance factor (CRF), optic nerve cupping, prelaminar tissue thickness, and lamina cribrosa depth and thickness were registered. A correlation matrix and multiple linear regression models were used to determine predictors of ONH changes. Results At 3 months after surgery, mean corneal compensated intraocular pressure (IOPcc) significantly decreased by 27.9% (p<00.001) and mean Goldmann-correlated IOP (IOPg) decreased by 30.52% (p<00.001). Mean CH increased and CRF decreased by 18.4% and 10.1%, respectively (p<00.001). There was a significant reversal of ONH cupping mainly due to a prelaminar tissue thickening (p<00.001). Significant associations were found between ONH cupping reversal and prelaminar tissue thickening with preoperative IOPcc (p = 0.046), IOPg (p = 0.02), and CRF (p = 0.002) and with changes in IOP, CH, and CRF (p<00.001, p = 0.004, p = 0.018, respectively) after surgery. Conclusions Corneal hysteresis increased and CRF decreased significantly 3 months after DS. Corneal resistance factor was the single largest preoperative factor influencing cupping reversal changes. Despite the influence of preoperative variables, postoperative IOP reduction was the only independent factor influencing changes observed in the ONH after surgery.

Influence of corneal biomechanical properties on IOP indices in patients with keratoconus

The Eye ◽  
2019 ◽  
Vol 21 (128) ◽  
pp. 15-19
Author(s):  
Irina Bubnova ◽  
Veronica Averich ◽  
Elena Belousova
Keyword(s):  
Disease Progression ◽  
Corneal Thickness ◽  
Central Zone ◽  
Biomechanical Properties ◽  
Resistance Factor ◽  
Corneal Resistance Factor ◽  
Mean Values ◽  
Coefficient Of Elasticity ◽  
D Values ◽  
Corneal Biomechanical Properties

Purpose: Evaluation of corneal biomechanical prop¬erties and their influence on IOP indices in patients with keratoconus. Material and methods. The study included 194 eyes with keratoconus (113 patients aged from 23 to 36 years old). Corneal refraction in central zone varied from 48.25 to 56.75 D, values of corneal thickness ranged from 279 to 558 μm. Patients were divided into 4 groups according to Amsler classification: I stage – 40 eyes; II stage – 78 eyes; III stage – 54 eyes and IV stage – 22 eyes. Standard ophthal¬mological examination was carried out including pneumo¬tonometry. IOP indices and values of biomechanical prop¬erties were evaluated by dynamic bidirectional pneumatic applanation and pneumatic impression. Results. Study of corneal biomechanical properties in patients with keratoconus showed a decrease of such biomechanical indices as corneal hysteresis (CH) on aver¬age to 8.42±1.12 mm Hg, corneal resistance factor (CRF) – to 7.45±0.96 mm Hg, coefficient of elasticity (CE) – 5.35± 0.87 mm Hg. Values of these indices strongly depended on the stage of keratoconus. In the whole sample, the aver¬age corneal compensated IOP (IOPcc) amounted to 15.08± 2.43 mm Hg, Goldman IOP (IOPg) was 11.61±2.37 mm Hg and pneumatic tonometry IOP (IOPp) was 10.13±2.94 mm Hg. IOPcc indices didn’t have any statistically significant differ¬ence in dependence on the stage of keratoconus (р>0.473), while in process of disease progression IOPg and IOPp indi¬ces showed statistically significant decrease of mean values. Conclusion. Progression of keratoconus led to a de¬crease in corneal biomechanical properties which deter¬mine reduction of such indices as IOPg and IOPp in contrast to IOPcc.

scholarly journals Biomechanical Properties in Different Types of Thin Corneas in Menoufia Population

2020 ◽  
Author(s):  
Adel Galal Zaky ◽  
Amin Faisal Ellakwa ◽  
Ahmed Ibrahim Basiony
Keyword(s):  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Study Groups ◽  
Biomechanical Properties ◽  
Resistance Factor ◽  
Corneal Hysteresis ◽  
Corneal Resistance Factor ◽  
Significant Difference ◽  
Different Types ◽  
The Mean

Abstract Background:To evaluate and compare corneal hysteresis (CH) and corneal resistance factor (CRF) in normal thin (NT) healthy corneas with central corneal thickness (CCT) 470-500 µm with matched thickness in keratoconus suspect (KCS) and keratoconus (KC) and eyes.Methods: A total of 103 eyes in three groups were included prospectively: NT, KCS and KC groups based on clinical examination and pentacam findings. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured by the ocular response analyzer (ORA). CCT ,CH and CRF were compared between the three groups and statistically analyzed by variance tests.Results:The three groups consisted of 44 NT, 26 KCS, and 33 KC. The mean CH measured was 8.689 ± 1.775, 9.051 ± 1.1190 and 8.129 ± 0.8539 mmHg in NT, KCS and KC eyes, respectively. The mean CRF was 8.441 ± 1.663, 8.337 ± 1.114 and 7.2422 ± 1.3110 mmHg in NT, KCS and KC eyes, respectively. Within range of central corneal thickness (470 – 500 µm), only mean CRF was statistically significantly different between the NT and KC (P < 0.05); there was no statistically significant difference between NT and KCS, nor the mean CH between each group (P > 0.05).Conclusions: CRF only can be helpful in differentiating KC from NT eyes; KCS could not be predicted with either corneal biomechanical metrics. No benefit from CH in differentiating between the three study groups.

Association between corneal biomechanical properties and optic nerve head morphology in newly diagnosed glaucoma patients

2012 ◽  
Vol 40 (7) ◽  
pp. 682-688 ◽  
Author(s):  
Tiago S Prata ◽  
Verônica C Lima ◽  
Lia M Guedes ◽  
Luis G Biteli ◽  
Sergio H Teixeira ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Biomechanical Properties ◽  
Newly Diagnosed ◽  
Head Morphology ◽  
Corneal Biomechanical Properties

Anterior Lamina Cribrosa Surface Position in Idiopathic Intracranial Hypertension and Glaucoma

2016 ◽  
Vol 27 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Jenni M. Villarruel ◽  
Xiao Q. Li ◽  
Daniella Bach-Holm ◽  
Steffen Hamann
Keyword(s):  
Optic Nerve ◽  
Intracranial Hypertension ◽  
Optic Nerve Head ◽  
Idiopathic Intracranial Hypertension ◽  
Open Angle Glaucoma ◽  
Fluid Pressure ◽  
Lamina Cribrosa ◽  
Enhanced Depth Imaging ◽  
Mean Deviation ◽  
Control Subjects

Purpose To compare the anterior lamina cribrosa (LC) surface position in patients with idiopathic intracranial hypertension (IIH), primary open-angle glaucoma (high-tension glaucoma [HTG] and normal-tension glaucoma [NTG]), and healthy controls using enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT). Methods This was a retrospective, cross-sectional observational study of 11 eyes with IIH, 20 eyes with HTG, 20 eyes with NTG, and 37 control eyes. Serial horizontal B-scans of the optic nerve head were obtained using EDI-OCT. The LC depth, defined as the distance from the Bruch membrane opening plane to the anterior LC surface, was manually measured on selected B-scans covering the central three-quarters of the optic nerve head in each eye. Results Mean LC depth in patients with IIH (325.2 ± 92.1 µm) was significantly (p<0.01) decreased compared to control subjects (387.8 ± 53.9 µm). In HTG, the mean LC depth (493.0 ± 115.2 µm) was significantly increased compared to NTG (376.6 ± 27.1 µm, p<0.05) and control subjects (332.7 ± 53.1 µm, p<0.001). The trans-LC pressure difference (TLPD) (intraocular pressure − cerebrospinal fluid pressure) was positively correlated with the LC depth (r = 0.96, p<0.001) and inversely correlated with visual field perimetric mean deviation in patients with IIH (r = -0.88, p<0.001). Conclusions The LC is positioned anteriorly in patients with IIH and posteriorly in glaucomatous eyes compared to normal controls. The positional changes of the LC could be a result of the TLPD between the intraocular and intracranial pressure compartments.

scholarly journals Biomechanical Properties in Different Types of Thin Corneas in Menoufia Population

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Adel Galal Zaky ◽  
Amin Faisal Ellakwa ◽  
Ahmed Ibrahim Basiony
Keyword(s):  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Study Groups ◽  
Biomechanical Properties ◽  
Resistance Factor ◽  
Corneal Hysteresis ◽  
Corneal Resistance Factor ◽  
Significant Difference ◽  
Different Types ◽  
The Mean

Background. To evaluate and compare corneal hysteresis (CH) and corneal resistance factor (CRF) in normal thin (NT) healthy corneas with central corneal thickness (CCT) of 470–500 μm with matched thickness in keratoconus suspect (KCS) and keratoconus (KC) eyes. Methods. A total of 103 eyes in three groups were included prospectively: NT, KCS, and KC groups based on clinical examination and Pentacam findings. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using the ocular response analyzer (ORA). CCT, CH, and CRF were compared between the three groups and statistically analyzed by variance tests. Results. The three groups consisted of 44 NT, 26 KCS, and 33 KC. The mean CH measured was 8.689 ± 1.775, 9.051 ± 1.1190, and 8.129 ± 0.8539 mmHg in NT, KCS, and KC eyes, respectively. The mean CRF was 8.441 ± 1.663, 8.337 ± 1.114, and 7.2422 ± 1.3110 mmHg in NT, KCS, and KC eyes, respectively. Within the range of central corneal thickness (470–500 μm), only mean CRF was statistically significantly different between the NT and KC ( P < 0.05 ); there was no statistically significant difference between NT and KCS, nor was the mean CH between each group ( P > 0.05 ). Conclusions. CRF only can be helpful in differentiating KC from NT eyes; KCS could not be predicted with either corneal biomechanical metrics. There was no benefit from CH in differentiating between the three study groups.

scholarly journals Use of Corneal hysteresis and Corneal Resistance Factor in Target Intraocular Pressure Estimation in Patients with Early Primary Open Angle Glaucoma

2021 ◽  
Author(s):  
Moataz Sallam ◽  
Mervat E. Elghareib
Keyword(s):  
Intraocular Pressure ◽  
Negative Correlation ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Significant Negative Correlation ◽  
Resistance Factor ◽  
Corneal Hysteresis ◽  
Open Angle ◽  
Corneal Resistance Factor ◽  
Early Primary

Abstract Purpose: To introduce a new method for estimation of the target intraocular pressure (TIOP) in naïve eyes with early primary open angle glaucoma (POAG) using Corneal hysteresis (CH) and corneal resistance factor (CRF).Methods: A prospective quasi-experimental study was conducted on naïve 90 eyes of 45 patients who were newly diagnosed with early primary open angle glaucoma (POAG). They were compared to 72 eyes of 36 normal subjects. The TIOP was determined for each eye. The IOP Goldmann (IOPg), IOP corneal-compensated (IOPcc), CH and CRF were estimated by Ocular Response Analyzer (ORA, Reichert) device. Measurements were taken for each patient prior to treatment and after 1, 3, 6, 9 and 12 months of receiving medications; either monotherapy or combination therapy.Results: For all patients, there was a significant negative correlation (p < 0.05) between IOP, either IOPg or IOPcc, and CH while a significant positive relationship (p < 0.05) existed between IOP and CRF. For patients with early POAG, The CH was significantly increased (p ≤ 0.001) while CRF was significantly decreased (p ≤ 0.001) when TIOP was achieved. At IOP levels higher than TIOP, CH value was lower than CRF with a significant negative correlation between them in contrast to controls. This correlation was reversed on reaching TIOP and CH values became higher than CRF similar to controls.Conclusion: CH, CRF and IOP measured by ORA can be used for TIOP estimation. This provides us with a guide for assessing the effectiveness of medications introduced to patients with POAG.

scholarly journals Choroidal microvasculature dropout is spatially associated with optic nerve head microvasculature loss in open-angle glaucoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min Kyung Song ◽  
Joong Won Shin ◽  
Jin Yeong Lee ◽  
Ji Wook Hong ◽  
Michael S. Kook
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Optical Coherence Tomography Angiography ◽  
Open Angle Glaucoma ◽  
Spatial Relationship ◽  
Vascular Supply ◽  
Open Angle ◽  
Regression Analyses ◽  
Angular Extent ◽  
Choroidal Vessels

AbstractThe presence of parapapillary choroidal microvasculature dropout (CMvD) may affect optic nerve head (ONH) perfusion in glaucoma patients, since parapapillary choroidal vessels provide vascular supply to the neighboring ONH. However, it remains to be determined whether the presence of parapapillary CMvD is associated with diminished perfusion in the nearby ONH. The present study investigated the spatial relationship between CMvD and ONH vessel density (ONH-VD) loss in open-angle glaucoma (OAG) eyes using optical coherence tomography angiography (OCT-A). This study included 48 OAG eyes with a single localized CMvD confined to the inferotemporal parapapillary sector and 48 OAG eyes without CMvD, matched for demographic and ocular characteristics. Global and regional ONH-VD values were compared between eyes with and without CMvD. The relationships between ONH-VD outcomes and clinical variables were assessed. ONH-VDs at the inferotemporal ONH sectors corresponding to the CMvD location were significantly lower in eyes with compared to those without CMvD. Multivariable linear regression analyses indicated that a lower inferotemporal ONH-VD was independently associated with CMvD presence and a greater CMvD angular extent (both P < 0.05). The localized presence of parapapillary CMvD in OAG eyes is significantly associated with ONH-VD loss in the neighboring ONH location, with a spatial correlation.

scholarly journals In vivo analysis of glaucoma-related features within the optic nerve head using enhanced depth imaging optical coherence tomography

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0180128 ◽  
Author(s):  
Tiago S. Prata ◽  
Flavio S. Lopes ◽  
Vitor G. Prado ◽  
Izabela Almeida ◽  
Igor Matsubara ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optic Nerve ◽  
Optic Nerve Head ◽  
Enhanced Depth Imaging ◽  
Optical Coherence ◽  
Depth Imaging ◽  
In Vivo Analysis ◽  
Imaging Optical Coherence Tomography
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