[Importance of the assay of T3 and T4 tears and plasma for the diagnosis of endocrine exophthalmos].

In the control subject, the thyroidal hormones have been found to be always present in similar quantities in both eyes tears. The proportion of T3 is much more important in the tears (23-40%) than in the plasma (1-2%). It is close to the concentration of deiodinated T4 found in many tissues. In ocular tissues, the T3 is thus very little or even not broken down. This led us to define the tear plasma relationship parameters. We studied lacrimo-plasmatic thyroidal parameters in cases with thyroidal dysfunction without ocular affection: 3 cases of hyperthyroidism, and 2 of hypothyroidism, to study modifications in case of endocrinal problems only. We also studied various types of exophthalmos: 31 cases of endocrine exophthalmos, whether the thyroidal plasma values were normal or not, and 2 cases of exophthalmia with expansive orbital hyperplasia in which there had been no previous thyroidal disturbance. An exophthalmia patient studied, including those with expansive orbital tissue, important changes, specific enough were associated in the tear/plasma parameters, correlated with the changes in the retro-orbital muscular tissues or fat detected by scanning. The study of these parameters, lacrimal thyroid is thus interesting for the diagnosis of endocrine exophthalmos and shows that only a local modification of the metabolism of T3 and T4, mainly from deiodination , process is probably implied in the pathology of these exophthalmos.