Optic disc cupping in arteritic anterior ischemic optic neuropathy resembles glaucomatous cupping.

Five cases of anterior ischemic optic neuropathy secondary to biopsy-proven giant cell arteritis are presented. In each case, cupping of the optic disc, which closely resembled glaucomatous cupping, was observed in the affected eye. The presence of glaucoma was ruled out on the basis of normal intraocular pressures and normal tonographic measurements of facility of outflow. These cases indicate that arteritic ischemic optic neuropathy can result in optic disc cupping, which closely resembles glaucomatous cupping. The similarities in the appearance of cupping of these discs with that seen in eyes with glaucoma suggest that the pathogenesis of cupping in glaucoma and in arteritic ischemic optic neuropathy may share some common mechanisms.

Why do some people go blind from glaucoma?

Retrospective analysis of patients blinded by glaucoma has revealed a need to educate patients to the significance of premonitory symptoms, to investigate a higher incidence of blindness from open-angle glaucoma among blacks than whites, and to define the goals of therapy in relation to presenting pathology. Responding to this third need, circumstances of patients followed for 20 to 40 years with extensive documentation relating to open-angle glaucoma were analyzed. Some eyes with normal discs and fields were found to tolerate a tension of 30 mm Hg for many years without need of treatment. But, when abnormalities ranging from early glaucomatous cupping to advanced visual field defects were present on initial evaluation, progressive loss of field tended to occur at lower tensions. It appears that the worse the initial condition of the eye, the lower the tension needs to be to prevent further loss or blindness.

Progressive low-tension glaucoma: treatment to stop glaucomatous cupping and field loss when these progress despite normal intraocular pressure.

Our thesis, inspired by the experience and teaching of Paul A. Chandler, is that after the optic discs have developed cupping and atrophy from elevated intraocular pressure they tend to become abnormally vulnerable and, in some cases, may continue to deteriorate even if the intraocular pressure is brought to the teens. At this stage they behave the same as in eyes with so-called low-tension glaucoma, which have developed progressive cupping and atrophy with pressures always in the teens. In either case, we find that the progression of cupping and field loss can be stopped by reducing the intraocular pressure to lower levels, preferably to 10 mm Hg or less. We have found that such low pressures are most reliably attained by surgery, using a special technique we call the shell tamponade filtration procedure, which involves the use of a glaucoma shell in conjunction with standard (full-thickness sclerostomy) filtration operations and certain specific operative and perioperative maneuvers. We present nine case reports illustrating our thesis. Glaucomatous cupping and loss of visual field were progressing relentlessly at normal pressures in each case. This progressive deterioration was shown to be arrested by reduction of the pressure to less than 12 mm Hg in 13 eyes.