The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. II. Clinical studies on the mechanism of intraocular pressure elevations.

The mydriasis provocative test with 1% cyclopentolate (CPT) was performed on 218 patients with suspected or untreated open-angle glaucoma, on 431 eyes in all. Significant IOP elevations (larger than or equal to 8 mmHg) were demonstrated in 21 eyes of 18 patients. The present paper analyses the responder group and presents some other investigation results and clinical findings to throw additional light on the mechanism of IOP elevation in responders. The responders did not differ from the other patients of the material in age or sex. Patients with capsular glaucoma constituted the biggest group among the responders. 48% of the significant IOP elevations during CPT were encountered in eyes with pseudoexfoliation (PE) and open-angle glaucoma. A positive response during CPT was statistically significantly more common in PE eyes than in eyes without PE. Capsular glaucoma was diagnosed immediately or later in all PE eyes which displayed a larger than or equal to 5 mmHg IOP elevation during the CPT. In addition to the importance of pigment in PE eyes, PE material may play a certain role in the elevation of IOP . The mechanism of this role is not known. No correlation was established between the results of the water drinking test and the CPT. The mechanism that causes the elevation of IOP must be quite different in these two tests. Nor was a statistically significant difference observed in the incidence of cataract, the maximal variation of IOP in the 48-h tension curve, the occurrence of cupping of the optic disc or visual field defects between the responder and non-responder eyes in the glaucomatous group.