Combined Open-Angle and Angle-Closure Glaucoma

The obstruction to aqueous outflow in primary open-angle glaucoma is due mainly to abnormalities within or just beyond the trabecular meshwork (TM), whereas in angle-closure glaucoma the cause of obstruction to aqueous outflow is contact between the periphery of the iris and the corneoscleral TM, preventing access of aqueous humor to the normal aqueous outflow system. There is no reason why both conditions could not occur in the same eye. Because each has an independent basis, a certain number of coincidences of this sort can be expected. ¹ On the other hand, there are more cases of “residual open-angle glaucoma” after laser iridectomy than would be expected by chance (see Chapter 56).