[Significance of the intolerance index in glaucoma].

In 1979 Vodovozov proposed a new individualized index-the intolerance index-for the prognosis of glaucoma. It is calculated as the difference between tonometric and tolerable intraocular pressure, determined after the intake of hypotensive drugs. The lowered tonometric value which coincides with the maximum improvement in visual function (reduced size of the blind spot, enlarged visual field) is considered the individually compatible (tolerable) level of intraocular pressure. The tolerable intraocular pressure and the intolerance index were determined in 379 eyes of 213 patients with open-angle glaucoma; the follow-up period ranged from 18 months to 5 years. Statistical evaluation of the data obtained showed a significant difference between the values for the intolerance index of glaucomatous eyes with stabilized and nonstabilized visual function. In stabilized glaucoma the intolerance index is at most 4 mm Hg. If this is exceeded, one ought to intensify medication or resort to surgery. Lobstein's index (the difference between the mean blood pressure in the central retinal artery and the intraocular pressure) was found to be unreliable in assessing the prognosis.