The central goal of glaucoma treatment is the reduction of intraocular pressure (IOP) by means of medication and/or surgery, in order to prevent further disease progression for as long as possible. Stabilising visual field defects and saving papillary neural tissue are seen as the optimal achievable aims in glaucoma therapy. We performed a systematic literature search and analysis of the published articles dealing with neuroprotection and functional improvement by IOP reduction in glaucoma. On this basis, the known options for anatomical and functional recovery of formerly lost structures and functions will be elucidated. Several studies - some large - have provided evidence for anatomical improvement at the optic nerve head and functional improvement in the results of visual field tests. After glaucoma treatment, there is anatomical and functional improvement in some patients. However, improvement is mostly detectable in patients whose IOP was greatly reduced.