A study in the latest edition of the journal The Lancet Neurology reports on the possibility of repairing the optic nerve. Damage to the optic nerve is inevitably associated with blindness or significant visual impairment and has long been held to be irreversible. Once diagnosed, for example in patients with glaucoma, medication or surgery can help stem further damage, but can only preserve what sight remains. Treatment cannot restore vision already lost as a result of damage to nerve fibres.
It has been known for decades that a particular type of cell in the human body, called a Schwann cell, can be transplanted and can repair myelin. Myelin is a substance that forms electrical insulation around certain nerve cells and is key to enabling the nervous system to function. If damaged, messages to and from the brain fail or are impaired, affecting the senses.
In the case of the optic nerve, it is a person’s vision that is lost or impaired. The optic nerve is part of the central nervous system and cannot regenerate or repair itself because of natural inhibitors in the body that block its re-growth.
Various alternative approaches to try to stimulate nerve fibre growth are under research, but their success depends on stopping natural inhibitors from working. Put simply, the study reported in The Lancet focuses on introducing antibodies to block the natural inhibitors, leaving nerve fibres free to grow. The results have been reported as somewhat equivocal, but do indicate justification for further, more extensive research in this area and confirm that it may be feasible to remyelinate nerves using antibody therapy.
Andrew Clayton of Penningtons Manches’ clinical negligence team explains: “There are many factors still to overcome and this research marks very tentative first steps in the process of repairing nerves by promoting the regrowth of myelin. It is yet to be established whether regenerating optic nerve cells, even if it proves possible, will in itself pave the way for functional sight to be regained. The research is inconclusive, but the potential benefits are immeasurable to those hopeful that they might one day have a clinical solution to improve or even restore lost sight.”