Reverse Pupillary Block Research Articles

Exercise and Reversed Pupillary Block in Pigmentary Glaucoma

The effect of exercise on the iris contour was investigated with ultrasound biomicroscopy in two patients with pigmentary glaucoma. Ten minutes of bicycle exercise strikingly increased the iris concavity. After Nd:YAG laser iridotomy the iris remained plane after a repeated exercise test. We believe that exercise increased the ocular pulse, which augmented cyclic aqueous movements through the pupil. Combined with a reverse pupillary block, the resulting intermittent excessive iris concavity caused pigment dispersion.

Prevention of Blinking Alters Iris Configuration in Pigment Dispersion Syndrome and in Normal Eyes

To examine the effect of blinking on iris configuration and aqueous humor distribution between the posterior and anterior chambers in eyes with pigment dispersion syndrome compared with healthy eyes. High-resolution, anterior segment ultrasound biomicroscopy was performed on ten eyes of ten patients with untreated pigment dispersion syndrome and on ten control subjects. Patients were scanned continuously for 15 minutes or until the maximal change in iris configuration occurred. During this time, the eyelids were held open mechanically, and blinking was prevented. Eyes then were rescanned immediately after blinking. Initial iris configuration was concave in all eyes with pigment dispersion syndrome, whereas in control eyes it was concave in four eyes, planar in four eyes, and convex in two eyes. Iridozonular contact occurred in eyes with pigment dispersion syndrome only. Iridolenticular contact was greater in eyes with pigment dispersion syndrome than in control eyes. Analysis of covariance controlling for age, sex, and refractive error showed pigment dispersion syndrome to be a significant predictor of increased iris concavity. During continuous scanning, the mean change in iris position, from most concave to most convex, and mean time to the maximal change in iris configuration were greater for eyes with pigment dispersion syndrome than in control eyes and were related to the degree of initial iris concavity only (analysis of covariance). In six eyes with pigment dispersion syndrome, the eye cup was removed, normal blinking was permitted, and the eye was rescanned. The iris resumed a concave configuration in all eyes. Increased iris concavity in pigment dispersion syndrome appears to be related to increased iridolenticular contact. This creates an anatomic configuration that predisposes to reverse pupillary block. The accumulation of aqueous humor in the posterior chamber, when blinking is prevented, alters iris position in pigment dispersion syndrome and in healthy eyes and increases iridozonular and iridociliary-process distances while minimizing iridolenticular contact. Normal blinking appears to create transient vector forces which promote aqueous humor flow from the posterior to anterior chamber.

Ultrasound Biomicroscopy in Pigment Dispersion Syndrome

To examine the positional relations of the iris, lens, ciliary processes, and zonules in eyes with the pigment dispersion syndrome (PDS). High-resolution, anterior segment ultrasound biomicroscopy was performed on 16 untreated eyes of 11 patients with PDS. Scanning was repeated on four eyes after miotic treatment and four eyes after laser iridotomy. Mid-peripheral iris concavity could be demonstrated in 56%, irido-zonular contact in 25%, and irido-ciliary process contact in 75% of untreated eyes with PDS. Repeat scanning after laser iridotomy or pilocarpine therapy showed resolution of the iris concavity and irido-zonular contact in all eyes receiving these therapies. Irido-ciliary process contact persisted in some eyes. The authors' findings demonstrate the structural relations among the iris, lens, zonules, and ciliary processes in vivo that characterize the PDS. Miotic therapy and laser iridotomy eliminate the iris concavity in all patients with this finding, supporting the hypothesis of reverse pupillary block. Irido-ciliary process contact may be another mechanism causing release of pigment. This issue merits further clinical and histologic study.

Pigmentary Dispersion Syndrome and Pigmentary Glaucoma: A New Mechanism Concept, A New Treatment, and A New Technique

Reverse pupillary block is introduced as a new cataract-implant complication and as the principle mechanism in pigmentary dispersion syndrome (PDS) and pigmentary glaucoma (PG), causing posterior iris bowing and zonular rubbing. This mechanism was investigated by performing laser iridotomy on six patients. Following surgery, the iris moved forward completely and permanently to the planar position. A new technique, locating the iridotomy by transillumination, reduced the laser energy needed for iridotomy. Laser iridotomy located with transillumination is recommended as the treatment for iris-zonular rubbing in PDS and PG caused by reverse pupillary block.