Ignite Creation Date:
2024-05-05 @ 12:11 PM
Last Modification Date:
2024-10-26 @ 9:21 AM
Study NCT ID:
NCT00262626
Status:
TERMINATED
Last Update Posted:
2005-12-07
First Post:
2005-12-05
Brief Title:
The Canadian Glaucoma Study
Sponsor:
Dalhousie University
Organization:
Dalhousie University
Study Overview
Official Title:
A Multicentre Study on the Risk Factors for the Progression of Open-Angle Glaucoma
Status:
TERMINATED
Status Verified Date:
2003-06
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
Glaucoma is a disease which affects between one and two percent of all individuals aged over 40 years According to recent Canadian National Institute for the Blind figures it is the second largest specific cause of blindness in this country The most common form of glaucoma open-angle glaucoma is incipient and typically results in a progressive loss of vision without symptoms due to damage to a structure inside the eye called the optic nerve head Although the most important known risk factor for the development of open-angle glaucoma is high intraocular pressure the pressure within the eyeball a number of researchers have shown that a sizeable proportion of patients continue to lose vision in spite of successful treatment to lower their intraocular pressure This finding suggests that there may be additional risk factors involved Ocular vasospasm the inability of certain blood vessels to dilate and increase blood flow according to the needs the eye and vascular disease are among other factors implicated but their roles have not yet been fully investigated The Canadian Glaucoma Study Group proposes to investigate the role of risk factors including vasospasm and vascular disease involved in the progression of open-angle glaucoma We will recruit 410 patients with open-angle glaucoma across 4 centres Halifax Vancouver Montreal and Toronto who will be treated by experienced investigative ophthalmologists according to a uniform standard protocol to ensure that all patients are managed in the same manner The patients will be followed meticulously with the most modern and accurate tests available every four months for a period of 5 years to determine whether progression has taken place Visual function will be measured using two techniques called conventional perimetry and blue-on-yellow perimetry and optic nerve heads will be examined with a special scanner capable of three-dimensional imaging By defining both the ocular and systemic profiles of patients who progress and do not progress we may be able to identify which patients will benefit from the standard treatment of intraocular pressure reduction such as that prescribed in the study More importantly we will identify the characteristics of patients who do not benefit from standard treatment so that alternative ones may be developed Such studies are clearly necessary but have not yet been conducted We believe that the proposed study will increase our knowledge of open-angle glaucoma and reduce its impact on blindness and visual disability
Detailed Description:
Elevated intraocular pressure is the most important known risk factor for the development and progression of open-angle glaucoma While pressure reduction is beneficial in many cases a significant proportion of patients continue to progress despite clinically acceptable pressure levels Many investigators have found no differences in pressure characteristics between progressing and non-progressing patients highlighting our current inability to identify which patients will respond to pressure reduction It is likely that this inability stems from our poor understanding of the risk factors both ocular and systemic for progression and the probability that glaucoma is a disease with multiple pathogenic mechanisms
In this application the Canadian Glaucoma Study Group proposes a multi-centre prospective study with the objective of characterising the risk factors associated with the progression of open-angle glaucoma We will determine sub-groups of patients with regard to the type of progression thereby allowing us to identify the ocular and systemic profiles of patients who are likely to and not likely to benefit from intraocular pressure reduction
Our hypotheses are
i The relationship between intraocular pressure characteristics during follow-up and survival rates with regard to progression of open-angle glaucoma is weak
ii Patients with vasospasm have a higher survival rate than patients without vasospasm with the clinical management prescribed in this study
iii Patients with vascular disease have a lower survival rate than patients without vascular disease with the clinical management prescribed in this study
We will test these hypotheses by following a total of 410 patients in 4 centres Halifax Vancouver Montreal and Toronto every 4 months for a period of 5 years using a uniform protocol for both the clinical management and study procedures Clinical management will involve at least 30 reduction in intraocular pressure from the baseline untreated value followed by an additional 20 or greater reduction after a progressive event The study procedures include conventional perimetry blue-on-yellow perimetry and scanning laser tomography of the optic nerve head and nerve fibre layer We will measure finger blood flow with both heat and cold provocation to assess each patients susceptibility to vasospasm and also obtain haematological biochemical and rheological profiles to assess the presence of vascular disease
Progression of either visual field and optic nerve head damage will be termed a progressive event occurring after a predefined change from baseline Events will be defined separately for each technique based on percentiles of empirically derived values of test-retest variability allowing a degree of standardisation between techniques Comparison of survival times between groups eg vasospastic and non-vasospastic will be made with Coxs survivorship analysis with a repeated measures model Where appropriate group comparisons will be made with the group t-test or Mann-Whitney test
If we can characterise more fully the risk factors for glaucomatous progression we may be able to identify the ocular and systemic profiles of patients who will benefit from our current treatment of pressure reduction More importantly we can identify the profiles of patients who respond poorly to pressure reduction so that future research efforts can lead to the development and implementation of alternative therapy We believe that this is a significant study which will result in a better understanding of open-angle glaucoma and help reduce its impact on blindness and visual disability
In this application the Canadian Glaucoma Study Group proposes a multi-centre prospective study with the objective of characterising the risk factors associated with the progression of open-angle glaucoma We will determine sub-groups of patients with regard to the type of progression thereby allowing us to identify the ocular and systemic profiles of patients who are likely to and not likely to benefit from intraocular pressure reduction
Our hypotheses are
i The relationship between intraocular pressure characteristics during follow-up and survival rates with regard to progression of open-angle glaucoma is weak
ii Patients with vasospasm have a higher survival rate than patients without vasospasm with the clinical management prescribed in this study
iii Patients with vascular disease have a lower survival rate than patients without vascular disease with the clinical management prescribed in this study
We will test these hypotheses by following a total of 410 patients in 4 centres Halifax Vancouver Montreal and Toronto every 4 months for a period of 5 years using a uniform protocol for both the clinical management and study procedures Clinical management will involve at least 30 reduction in intraocular pressure from the baseline untreated value followed by an additional 20 or greater reduction after a progressive event The study procedures include conventional perimetry blue-on-yellow perimetry and scanning laser tomography of the optic nerve head and nerve fibre layer We will measure finger blood flow with both heat and cold provocation to assess each patients susceptibility to vasospasm and also obtain haematological biochemical and rheological profiles to assess the presence of vascular disease
Progression of either visual field and optic nerve head damage will be termed a progressive event occurring after a predefined change from baseline Events will be defined separately for each technique based on percentiles of empirically derived values of test-retest variability allowing a degree of standardisation between techniques Comparison of survival times between groups eg vasospastic and non-vasospastic will be made with Coxs survivorship analysis with a repeated measures model Where appropriate group comparisons will be made with the group t-test or Mann-Whitney test
If we can characterise more fully the risk factors for glaucomatous progression we may be able to identify the ocular and systemic profiles of patients who will benefit from our current treatment of pressure reduction More importantly we can identify the profiles of patients who respond poorly to pressure reduction so that future research efforts can lead to the development and implementation of alternative therapy We believe that this is a significant study which will result in a better understanding of open-angle glaucoma and help reduce its impact on blindness and visual disability
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None