Optic Nerve Head and Retinal Nerve Fiber Layer Analysis

Abstract

Objective-To evaluate the current published literature on the use of optic nerve head (ONH) and retinal nerve fiber layer (RNFL) measurement devices in diagnosing open-angle glaucoma and detecting progression. Results-There were no studies classified as having the highest level of evidence (level I). The ONH and RNFL imaging instruments reviewed in this assessment were determined to be highly effective in distinguishing eyes with glaucomatous visual field (VF) loss from normal eyes without VF loss, based on level II evidence. In addition, some studies demonstrated that parameters from ONH or RNFL imaging predicted the development of VF defects among glaucoma suspects. Studies on detecting glaucoma progression showed that although there was often agreement on progression between the structural and functional (VF) tests, a significant proportion of glaucoma patients progressed by either the structural or the functional test alone. MethodsConclusions-The ONH and RNFL imaging devices provide quantitative information for the clinician. Based on studies that have compared the various available technologies directly, there is no single imaging device that outperforms the others in distinguishing patients with glaucoma from controls. Ongoing advances in imaging and related software, as well as the impracticalities associated with obtaining and assessing optic nerve stereophotographs, have made imaging increasingly important in many practice settings. The information obtained from imaging devices is useful in clinical practice when analyzed in conjunction with other relevant parameters that define glaucoma diagnosis and progression.

Detailed Illustration of the Visual Field Representation along the Visual Pathway to the Primary Visual Cortex: A Graphical Summary

“…in the primary visual cortex (V1) in response to appropriate stimuli [3]. There are numerous ophthalmological methods to determine neuronal reasons for impaired vision [4,5]. Among them, we can find quantification (1) of the retinal nerve fiber layer (RNFL) thickness; (2) of the optic nerve head morphology; (3) of visual field defects by perimetry; (4) of the spatial-temporal contrast sensitivity, and (5) of the visual evoked potential.…”

Performance of GDx and HRT in the Finnish Evidence-Based Guideline for Open-Angle Glaucoma

“…These results are in general agreement with the specificity reported by the earlier authors for photographic and imaging criteria. 12 In contrast, the diagnostic performance of the Finnish guideline in the participants from Source 2 produced a high number of positives. Group 2 is not a conventional 'case or glaucoma' group and cannot be considered as the glaucoma group.…”

Influence of pupil dilation on retinal nerve fibre layer measurements with spectral domain OCT

“…5 Time-domain OCT, first introduced in 1995, 6,7 has become widely used to obtain RNFL measurements in eyes with glaucoma. [8][9][10] Recently, advances in technology allowed the development of spectral-domain OCT (SD-OCT), which provides faster acquisition, better resolution, and improved visualization of retinal morphology. 8 By using the advanced technology of SD-OCT, the Cirrus HD-OCT acquires data about 70 times faster (27 000 vs 400 A-scans per second) and with better resolution (5 vs B10 mm of axial resolution in tissue) when compared to the first generation of OCT. 9,11 Furthermore, some studies have indicated that time-domain OCT requires pupil dilation for the acquisition of good quality images of the retina and RNFL.…”

“…[8][9][10] Recently, advances in technology allowed the development of spectral-domain OCT (SD-OCT), which provides faster acquisition, better resolution, and improved visualization of retinal morphology. 8 By using the advanced technology of SD-OCT, the Cirrus HD-OCT acquires data about 70 times faster (27 000 vs 400 A-scans per second) and with better resolution (5 vs B10 mm of axial resolution in tissue) when compared to the first generation of OCT. 9,11 Furthermore, some studies have indicated that time-domain OCT requires pupil dilation for the acquisition of good quality images of the retina and RNFL. [11][12][13] Although the manufacturer of the Cirrus HD-OCT indicates that the images can be obtained without pupil dilation, there is no study in the literature investigating the effects of pupil dilation on the measurements obtained with this instrument.…”