scholarly journals Binocular Integrated Visual Field Deficits Are Associated With Changes in Local Network Function in Primary Open-Angle Glaucoma: A Resting-State fMRI Study

2022 ◽  
Vol 13 ◽  
Author(s):  
Giorgia Demaria ◽  
Azzurra Invernizzi ◽  
Daniel Ombelet ◽  
Joana C. Carvalho ◽  
Remco J. Renken ◽  
...  
Keyword(s):  
Visual Field ◽  
Functional Connectivity ◽  
Resting State ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Local Network ◽  
Open Angle ◽  
Significant Difference ◽  
Global Brain ◽  
Healthy Participants

In glaucoma participants, both structural and functional brain changes have been observed, but we still have insufficient understanding of how these changes also affect the integrity of cortical functional networks, and how these changes relate to visual function. This is relevant, as functional network integrity may affect the applicability of future treatments, as well as the options for rehabilitation or training. Here, we compare global and local functional connectivity in local and global brain networks between glaucoma and control participants. Moreover, we study the relationship between functional connectivity and visual field (VF) loss. For our study, 20 subjects with primary open-angle glaucoma (POAG) and 24 age-similar healthy participants were recruited to undergo an ophthalmic assessment followed by two resting-state (RS) (f)MRI scans. For each scan and for each group, the ROIs with eigenvector centrality (EC) values higher than the 95th percentile were considered the most central brain regions (“hubs”). Hubs for which we found a significant difference in EC in both scans between glaucoma and healthy participants were considered to provide evidence for network changes. In addition, we tested the notion that a brain region's hub function in POAG might relate to the severity of a participant's VF defect, irrespective of which eye contributed mostly to this. To determine this, for each participant, eye-independent scores were derived for: (1) sensitivity of the worse eye – indicating disease severity, (2) sensitivity of both eyes combined – with one eye potentially compensating for loss in the other, or (3) difference in eye sensitivity – potentially requiring additional network interactions. By correlating each of these VF scores and the EC values, we assessed whether VF defects could be associated with centrality alterations in POAG. Our results show that no functional connectivity disruptions were found at the global brain level in POAG participants. This indicates that in glaucoma global brain network communication is preserved. Furthermore, for the Lingual Gyrus, identified as a brain hub, we found a positive correlation between the EC value and the VF sensitivity of both eyes combined. The fact that reduced local network functioning is associated with reduced binocular VF sensitivity suggests the presence of local brain reorganization that has a bearing on functional visual abilities.

scholarly journals Binocular integrated visual field deficits are associated with changes in local network function in primary open-angle glaucoma: a resting-state fMRI study

2021 ◽  
Author(s):  
Giorgia Demaria ◽  
Azzurra Invernizzi ◽  
Daniel Ombelet ◽  
Joana Carvalho ◽  
Remco Renken ◽  
...  
Keyword(s):  
Visual Field ◽  
Functional Connectivity ◽  
Resting State ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Brain Regions ◽  
Local Network ◽  
Open Angle ◽  
Significant Difference ◽  
Global Brain

Recent brain imaging studies have shown that the degenerative eye damage generally observed in the clinical setting, also extends intracranially. Both structural and functional brain changes have been observed in glaucoma participants, but we still lack an understanding of whether these changes also affect the integrity of cortical functional networks. This is relevant, as functional network integrity may affect the applicability of future treatments, as well as the options for rehabilitation or training. Here, we compare global and local functional connectivity between glaucoma and controls. Moreover, we study the relationship between functional connectivity and visual field (VF) loss. For our study, 20 subjects with primary open angle glaucoma (POAG) and 24 age similar healthy participants were recruited to undergo a complete ophthalmic assessment followed by two resting state (RS) (f)MRI scans. For each scan and for each group, the ROIs with EC values higher than the 95th percentile were considered the most central brain regions (hubs). Hubs for which we found a significant difference in EC in both scans between glaucoma and healthy were considered to provide evidence for network changes. In addition, for each participant, behavioural scores were derived based on the notion that a brain regions hub function might relate to the: 1) sensitivity of the worse eye, indicating disease severity, 2) sensitivity of both eyes combined, with one eye potentially compensating for loss in the other, or 3) difference in eye sensitivity, requiring additional network interactions. By correlating each of these VF scores and the EC values, we assessed whether VF defects could be associated with centrality alterations in POAG. Our results show that no functional connectivity disruptions were found at the global brain level in POAG participants. This indicates that in glaucoma global brain network communication is preserved. Furthermore, a positive correlation was found between the EC value of the Lingual Gyrus, identified as a brain hub, and the behavioral score for the VF sensitivity of both eyes combined. The fact that reduced local network functioning is associated with reduced binocular VF sensitivity suggests the presence of local brain reorganization that has a bearing on functional visual abilities.

scholarly journals Corneal biomechanics and biomechanically corrected intraocular pressure in primary open-angle glaucoma, ocular hypertension and controls

2019 ◽  
Vol 104 (1) ◽  
pp. 121-126 ◽  
Author(s):  
Riccardo Vinciguerra ◽  
Salwah Rehman ◽  
Neeru A Vallabh ◽  
Mark Batterbury ◽  
Gabriela Czanner ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Visual Field ◽  
Ocular Hypertension ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Corneal Biomechanics ◽  
Mean Deviation ◽  
Open Angle ◽  
Corvis St ◽  
Significant Difference

AimsTo compare the biomechanically corrected intraocular pressure (IOP) estimate (bIOP) provided by the Corvis-ST with Goldmann applanation tonometry (GAT-IOP) in patients with high-tension and normal-tension primary open-angle glaucoma (POAG; HTG and NTG), ocular hypertension (OHT) and controls. Moreover, we compared dynamic corneal response parameters (DCRs) of the Corvis-ST in POAG, OHT and controls, evaluated the correlation between global visual field parameters mean deviation and pattern SD (MD and PSD) and DCRs in the POAG group.Methods156 eyes of 156 patients were included in this prospective, single-centre, observational study, namely 41 HTG and 33 NTG, 45 OHT cases and 37 controls. Central corneal thickness (CCT), GAT-IOP and bIOP were measured, GAT-IOP was also adjusted for CCT (GATAdj). DCRs provided by Corvis-ST were evaluated, MD and PSD were recorded by 24–2 full-threshold visual field. To evaluate the difference in DCRs between OHT, HTG and NTG, a general linear model was used with sex, medications and group as fixed factors and bIOP and age as covariates.ResultsThere was a significant difference between GAT-IOP, GATAdj and bIOP in NTG and HTG, OHT and controls. NTG corneas were significantly softer and more deformable compared with controls, OHT and HTG as demonstrated by significantly lower values of stiffness parameters A1 and highest concavity and higher values of inverse concave radius (all p<0.05). There was a significant correlation (p<0.05) between MD, PSD and many DCRs with POAG patients with softer or more compliant corneas more likely to show visual field defects.ConclusionsCorneal biomechanics might be a significant confounding factor for IOP measurement that should be considered in clinical decision-making. The abnormality of corneal biomechanics in NTG and the significant correlation with visual field parameters might suggest a new risk factor for the development or progression of NTG.

Effectiveness of Ayurvedic intervention in Primary Open Angle Glaucoma (Kaphaja Adhimantha) - A Case Study

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Dr. Ratheesh P. ◽  
Dr. Abhayadev A. ◽  
Dr. Varsha Sumedhan ◽  
Dr. Meghna P P. ◽  
Dr. Srinivasan M ◽  
...  
Keyword(s):  
Visual Field ◽  
Structural Changes ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Treatment Protocol ◽  
Clinical Findings ◽  
Field Analysis ◽  
Open Angle ◽  
Remarkable Change ◽  
Related Disorder

Glaucoma is a diverse group of disorders affecting the eye with a common characteristic potentially progressive optic neuropathy that is determined by both structural changes and functional deficit in which IOP is a key modifiable factor. In Primary Open Angle Glaucoma (POAG), IOP independent mechanisms of glaucomatous nerve damage and visual field loss with unobstructed angle of anterior chamber is observed. The patient has reported gradual diminution of peripheral aspect of visual field (Rt. eye - 6/12 and Lt. eye - 6/12 on Snellen’s distant vision chart) in both eyes for 2 years. There was marked peripheral field defect on both confrontation test and perimetry visual field analysis test. The disease shows clinical similarity with Kaphaja Adhimantha, a disease affecting the whole eye mentioned in Susruta Samhita and Ashtanga Hrudaya. It is a chronic disease comes under life style related disorder. Dukhena Roopam Pasyathi (distorted image or constricted visual field), Sirodukha (headache), Srava (watering), Kandu (itching), Pamsupoornatha (foreign body sensation), Aviladarsana (diminished vision) and Gourava (heaviness of eye and head) are the clinical findings explained in the context of Kaphaja Adhimantha. These clinical finding mentioned in classical literature shows resemblance with POAG. The meticulous deployment of kaphaja Abhisyandha- Adhimantha treatment protocol can be used to prevent the progression of ganglionic damage and preservation of eye sight. The logical interpretation on the basis of both subjective and objective clinical findings concluded the diagnosis as Kaphaja Adhimantha and treatment principle adopted was Apatharpana, Kaphahara, Abhisyandhahara and Srothovisodhana. After treatment his vision has improved as 6/6 (Rt. Eye) and 6/6 (Lt. Eye) and remarkable change in field analysis. The study discusses about the effectiveness of Ayurvedic management in POAG.

Change in Visual Field Progression Following Treatment Escalation in Primary Open-angle Glaucoma

2017 ◽  
Vol 26 (10) ◽  
pp. 875-880 ◽  
Author(s):  
Florent Aptel ◽  
Alain M. Bron ◽  
Yves Lachkar ◽  
Cédric Schweitzer
Keyword(s):  
Visual Field ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Open Angle ◽  
Visual Field Progression ◽  
Treatment Escalation
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