The well tempered crystal ball in normal tension glaucoma

Patients with chronic glaucoma are being referred at lower intraocular pressures (IOPs) than was the case in the 1980s,1 probably as a result of an enhanced awareness among optometrists of the changes in the optic nerve head in early glaucoma2 and the increasing use of routine visual field screeners.3 As the proportion of glaucoma patients designated as “normal tension” in our clinics approaches that of the prevalence studies, there is a greater need for accurate data on the natural history of the disease subtype(s) if we are to make logical decisions on therapeutic interventions.

As many patients with normal tension glaucoma (NTG) do not appear to deteriorate significantly over quite long periods of follow up, even when untreated,4 the identification of risk factors for progression in an individual may aid the decision making process concerning whether to treat, and if “yes”, how aggressively. Such data would appear particularly useful in the case of …