Argon Laser trabeculoplasty and Cyclotrabeculospasis are two common procedures in the treatment of open angle glaucoma. Anatomo-clinical correlation to clarify the exact mechanism of Argon Laser therapy is difficult. We recently used Cyclotrabeculospasis 180 degrees on a patient with open angle glaucoma who developed a choroidal Malignant Melanoma. The eye was enucleated. We studied the trabecular meshwork and Schlemm's canal and measured the inter-trabecular spaces and the opening of Schlemm canal with an ocular micrometer. Comparison of the slides relative to the treated and untreated sections in the same eye seem to confirm the hypothesis of direct traction on the trabecular meshwork by the phocoagulating tissues nearby.