Evaluating Optic Nerve Imaging Technologies
Digital imaging is now recommended as a clinical tool to enhance and facilitate the assessment of the optic nerve and RNFL in the management of glaucoma.
Techniques currently available to physicians for diagnosis, staging and monitoring of glaucoma include:
| Technology |
Parameters evaluated |
| Stereophotography |
Retinal/ONH reflectivity (color)
Surface topography (subjective)
RNFL thickness (subjective)
|
| RNFL photography |
RNFL reflectivity |
| Confocal Scanning Laser Opthalmoscopy |
Rim area
Surface shape of the RNFL |
| Scanning Laser Perimetry |
Retinal nerve fiber layer thickness
Temporal-Superior-Nasal-Inferior-Temporal (TSNIT) average
|
| Optical Coherence Tomography |
Retinal nerve fiber layer thickness
Thickness variation
|
It is important to note that all imaging technologies facilitate glaucoma diagnosis by providing quantitative measurements compared to normative data. The classifications are statistical; however glaucoma diagnosis is a clinical decision, based on all other aspects of the patient examination.
This resource center is designed to demonstrate the value of imaging technology in order to enhance clinical management of glaucoma. Bearing this in mind, the focus here is on the following imaging technologies for glaucoma management:
All three technologies use the characteristics of light and retinal tissue to assess the structure of the ONH and/or RNFL, although the precise physical principles of each technology differ. In addition to aiding early and accurate diagnosis of glaucoma, these imaging technologies can also be valuable in monitoring disease progression over time (i.e., longitudinal change detection). The different imaging technologies can be complementary and detect different abnormal features in the same patients.
As each of these technologies undergoes continual hardware and software updates, the capacity to detect structural change earlier in the disease continuum becomes more advanced; however, there are some limitations of these technologies that still need to be addressed.
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