Proper outcome measurements regarding glaucoma: the inadequacy of using intraocular pressure alone.

Physicians typically assess glaucoma treatment in terms of the effect on intraocular pressure (IOP). However, it is inappropriate to use IOP as the sole outcome measure for the management of glaucoma for several reasons: a) it is a precursor of disease, but not the disease itself. b) Most often, it is not the only factor responsible for glaucomatous damage. c) It suggests, wrongly, that IOP should be maximally lowered in all glaucoma patients. d) We are beginning to be able to assess more accurately other signs, not just precursors, of glaucomatous damage itself, most importantly, optic disc damage and visual field loss. Even though these signs are far more valuable than IOP in assessing the outcome of treatment, they, too, nevertheless, are ultimately subordinate to the effect of treatment on the patient's quality of life.