The ability to accurately and reliably determine whether a glaucoma patient's visual field is stabilized or is undergoing progressive loss is a vital aspect in their clinical management. The efficacy of treatment is usually based on this evaluation, in conjunction with other related clinical information, including the status of the optic nerve head and retinal nerve fiber layer. In some instances, changes in the appearance of the optic nerve head and alterations in the visual field reveal similar characteristics, as illustrated in Figures 1 and 2. Figure 1 presents a composite of optic nerve head photographs of the left eye of a glaucoma patient, that were obtained at our visual function testing center over six successive years. For illustration purposes, the optic disc photos are presented as monocular images, but each photo represents one half of a stereo pair. It can be observed that there is inferior neuroretinal rim thinning, inferior retinal vessel displacement and other features that indicate that there has been structural progression of glaucomatous damage. Figure 2 presents the 30-2 and 24-2 visual fields of the left eye for the six successive years, using the Full Threshold and SITA-Standard threshold test strategies. It can be observed that there is a superior visual field loss (nasal step) that develops and the progresses to become a superior arcuate scotoma. In this example, there is a reasonably good correlation between the structural damage to the optic nerve head and the functional visual field loss. However, there are also many instances in which the optic disc reveals progressive glaucomatous damage that is not evident for the visual fields, examples in which the optic disc appears stable but the visual field shows evidence of progressive loss, and other cases in which the damage revealed by the optic disc and visual field do not correlate well.
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