Sixteen glaucomatous patients were observed for a period of 7 to 21 months while echothiophate (Phospholine) iodide was applied to one eye for control of ocular pressure and other types of treatment were used in the contralateral eye as needed. Six of the patients received 0.06% or 0.12% echothiophate iodide but showed no change in their lenses during this period. Ten of the patients received 0.25% echothiopate iodide, and five of these did develop significant change in the appearance of the lens in the treated eye. The lens changes which seemed to be related to the application of echothiophate iodide tended to be nuclear and posterior subcapsular rather than anterior. Fine anterior subcapsular vacuoles which others have ascribed to echothiophate iodide were observed to be common in untreated elderly patients. The existence of specific lens changes attributable to echothiophate iodide seems open to question.