الفهرس 
Anatomy of retinal nerve fiber layerOnly 14 pages are availabe for public view
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Abstract
Glaucomatous optic nerve damage appears not only as a morphological change of optic disc but also as reduction in the thickness of RNFL and defect of the optic nerve axons causes RNFL thinning. In glaucoma patients, such an alteration in the thickness of RNFL may appear prior to vision defects caused by optic nerve defects, and thus the assessment of such an alteration has recently been found useful in the early diagnosis of glaucoma.
Many methods have been developed in the past years, aiming for earlier detection of glaucoma and more accurate follow up. Evaluation of structural damage in early glaucoma include RNFL analysis, ganglion cell layer analysis and optic nerve topography which can be obtained by different instruments:
• The Heidelberg Retina Tomograph (HRT) is a promising tool for monitoring patients with or at risk of glaucoma. The ability of the HRT to provide a precise change analysis over time may allow for early detection of subtle alterations in the topography of the optic nerve head. The HRT is also a useful tool for long-term follow-up of glaucomatous optic neuropathy.
• Scanning laser polarimetry (SLP) is the use of polarized light to measure the thickness of the retinal nerve fiber layer as part of a glaucoma workup. Although SLP technology can not directly measure RNFL thickness, it allows for an indirect calculation of the RNFL thickness measurement.
• Optical Coherence Tomography (OCT) is a diagnostic modality that provides high-resolution, cross-sectional imaging of ocular tissues. RNFL thickness measured by OCT may serve in distinguishing normal from glaucomatous eyes, even in the early stages of glaucoma and may help to differentiate various severities of glaucoma. OCT provides clinically relevant images that correlate well with histology which improves the diagnostic accuracy for glaucoma detection using this instrument.
Evaluation of functional glaucomatous damage is done by testing the visual field through automated perimetry techniques which include:
• Standard Automated Perimetry (SAP) is a gold standard of modern functional assessment. This type of testing is a big improvement in sensitivity, specificity and repeatability compared to kinetic perimetry.
• Frequency Doubling Perimetry (FDT) has shown to offer good sensitivity and specificity in the detection of early glaucoma and in distinguishing between mild, moderate, and severe visual field loss. It is considered as a promising tool in evaluating the progression of glaucomatous visual field loss.
• Short-wavelength automated perimetry (SWAP) is an early indicator for functional glaucomatous losses. SWAP deficits are predictive of the onset and location of future visual field loss, and they correlate well with structural damage associated with glaucoma.
The diagnosis of early glaucoma cannot be based on automated perimetry alone or OCT, HRT and SLP alone, but quantitative assessment of both structure (imaging) and function (automated perimetry) in glaucoma should be interpreted together to increase diagnostic accuracy.