THE MEASUREMENT OF CHANGE IN GRAVES OPHTHALMOPATHY

Precise measurements of treatment response are a prerequisite for corr ect interpretation of therapeutic benefit. In the field of Graves' oph thalmopathy we have relied for too long on methods of measurement that are poorly reproducible, subjective, and that often rely on indices d erived from aggregated measurements and subjective impressions. In con sequence, our conclusions about the benefits of particular therapies a re frequently controversial. Until the pathogenic agent of Graves' oph thalmopathy has been identified and is measurable, we are forced to li mit our observations to the consequences of the action of that agent. Two critically important consequences are swelling of the retrobulbar muscles and connective tissue and shortening of the extraocular muscle range of contraction. From these primary events all the clinical feat ures of Graves' ophthalmopathy are derived. Effective treatment of Gra ves' eye disease will affect at least one of five relevant measurement s. These are: lid fissure width, range of extraocular motion, diplopia fields, and volume of retrobulbar muscle and connective tissue. These measurements, selected to correspond to the claims of the particular therapy under study, are recommended as the indicators of choice in cl inical trials.