Structure Function Correlation in Primary Open Angle Glaucoma (STR_FN)
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|ClinicalTrials.gov Identifier: NCT02028572|
Recruitment Status : Completed
First Posted : January 7, 2014
Last Update Posted : December 30, 2014
Glaucoma is an optic neuropathy characterised by progressive degeneration of retinal ganglion cells and axons that leads to nerve fibre loss, optic disc cupping, and consecutive glaucomatous visual field defects. It is considered to be one of the major causes of blindness worldwide.
It is a well accepted fact least 25 - 40% of retinal ganglion cells need to be lost before statistically detectable visual field defects appear on automated visual field testing, which is also consistent with post-mortem histologic findings in glaucomatous eyes. Since the damage associated with glaucoma is irreversible, and retinal nerve fibre layer loss is considered as an early sign of glaucomatous damage, its early detection and prevention is warranted. Retinal nerve fibre layer studies can be undertaken through non - invasive, reproducible technologies such as optical coherence tomography, scanning laser polarimetry etc.
The purpose of the study is to evaluate the relationship between visual fields and retinal nerve fibre layer thickness as measured by Cirrus spectral domain optical coherence tomography with visual fields by Humphrey Field Analyser (HFA) in early and moderate primary open - angle glaucoma.
|Condition or disease|
|Primary Open Angle Glaucoma|
It is often said that the structural damage due to glaucoma precedes functional loss, it is not always clear in its interpretation. To define, which test shows up the earliest sign of glaucomatous damage would be difficult to predict, since the outcome can be influenced by many factors, such as the sensitivity of the test, inter - individual difference or the stage of the disease process itself. Studies on post-mortem retinal ganglion cells counts and SAP field loss in humans and monkeys lead to an observation that, on an average about 25% retinal ganglion cells loss leads to development of an afferent pupillary defect, 35% loss for visual field defects and 40% loss leads to worsening of visual acuity. It would be safe to state that a) the most important clinical challenge is early detection of glaucomatous damage and progression over a period of time; b) Both structural and functional tests are important in assessing early damage and progression; c) significant damage to the retinal ganglion cells can occur before standard tests detect a functional loss in vision. These have paved the way to the development of many studies on the structure - function correlation and stating linear models for the same. However these studies present a dilemma; is the structure - function relation on glaucoma, a statistical statement (a structural measure will reach significance before a functional test) or relational statement (statistical correlation between the structural and functional tests).
We propose to evaluate the structure - function correlation in early and moderate open - angle glaucoma by assessing the retinal nerve fibre layer thickness by Spectral Domain Optical Coherence Tomography and areas of decreased visual field sensitivity given by Humphrey 24 - 2 Swedish Interactive Threshold Algorithm Standard protocol of automated perimetry and determine any representational or statistical significance, if any between the two tests.
|Study Type :||Observational|
|Actual Enrollment :||130 participants|
|Official Title:||A Cross Sectional Study of Correlation Between Retinal Nerve Fibre Thickness Measured by Optical Coherence Tomography and Humphrey Visual Fields in Early and Moderate Open Angle Glaucoma|
|Study Start Date :||February 2013|
|Actual Primary Completion Date :||May 2014|
|Actual Study Completion Date :||June 2014|
Primary open angle glaucoma
Subjects diagnosed to have primary open angle glaucoma with intraocular pressure > 21 mm Hg and characteristic glaucomatous damage to the optic nerve.
- Correlation between retinal nerve fibre layer thickness measured by optical coherence tomography and mean sensitivity, mean deviation as reported by visual fields. [ Time Frame: The subjects shall be studied over an avergae period of 4 weeks from the presentation for the purpose of optical coherence tomography and visual field studies. ]
- Correlation between retinal nerve fibre layer thinning and scotomatous defects in visual fields in primary open angle glaucoma. [ Time Frame: The subjects shall be reviewed over an average period of 4 weeks to obtain the optical coherence tomography and visual field studies. ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02028572
|Vasan Eye Care Hospital|
|Chennai, Tamil Nadu, India, 600015|
|Study Director:||Dr.Venkatesh Sugantharaj, MS, DNB||Vasan Eye Care Hospital|
|Principal Investigator:||Dr.RAMESH HARIHARAN, MBBS,DNB||Vasan Eye Care Hospital|