Closure of previously patent laser iridotomies has been described as occurring early or late after the procedure. Early closure, occurring from minutes to hours after completion of the iridotomy, results from landsliding of iris pigment epithelium from above the site of the iridotomy or from large pigment particles floating in the posterior chamber, lodging in the iridotomy site, and occluding it.1 Late closure may occur due to occlusion by the settling of dispersed pigment and/or inflammatory debris into a small iridotomy and/or proliferation of pigment with bridging of the iridotomy and usually occurs after days to weeks. 1 In most cases, this pigment appears to come from the stroma, and the pigment plugging of the iridotomy is anatomically at the level of the iris stroma.
Iris pigment epithelial proliferation has been considered extremely rare and to our knowledge has not been previously described after laser iridotomy.2 Closure of iridotomies by proliferation of iris pigment epithelium has been alluded to in various reports, but published photographs indicate pigment proliferation plugging the iridotomy at the level of the stroma, not at the level of the iris pigment epithelium. We present 2 cases in which true regrowth of the iris pigment epithelium solely at the appropriate anatomic level resulted in recurrence of pupillary block.
A 57-year-old man underwent argon laser iridotomy in his right eye for appositional angle closure. Postsurgery, the angles were grade 2 and grade 3 open. The iridotomy was noted to be closed by iris pigment epithelial regrowth 30 months later. There was no filling of the stromal defect, which remained fully patent (Figure 1, left). Gonioscopy revealed 180° of appositional closure, while the remainder of the angle was grade slit-I. This was confirmed by ultrasound biomicroscopy (UBM; Paradigm Medical Laboratories Inc, Salt Lake City, Utah) (Figure 1, right). The pigment was easily dispersed with a few bursts of low energy argon laser, and the iridotomy has remained patent for 5 years without iris pigment epithelial regrowth.
Left, Clinical photograph demonstrating closure of argon laser iridotomy by iris pigment epithelial proliferation (arrow). Right, Ultrasound biomicroscopy demonstrating proliferation of iris pigment epithelium (arrow). C indicates cornea; I, iris; and CB, ciliary body.
A 71-year-old women with angle-closure glaucoma underwent argon laser iridotomy in her left eye. Postsurgery, the iridotomy was patent, and the angle was grade 3. Four months later, iris pigment epithelial regrowth was noted to occlude the iridotomy site and the angle was narrow (Figure 2). A touch-up laser procedure was performed, following which the iridotomy has remained patent.
Ultrasound biomicroscopy demonstrating closure of iridotomy by iris pigment epithelium pupillary block (arrow). AC indicates anterior chamber; C, cornea; I, iris; and CB, ciliary body.
Pigment proliferation has been implicated in closure of iridotomies created by both argon and Nd:YAG lasers but is more commonly seen with those made with the argon laser. 1,3 What has been termed late closure classically occurs anatomically at the level of the iris stroma within a few weeks to months after the procedure.4,5 This type of closure rarely occurs after the iridotomy has been patent for longer.3 It is not really clear whether this proliferation is of pigment epithelium or stromal pigment or both. Thermal drainage to the iris pigment epithelium surrounding the iridotomy may be responsible.3
Our cases differ from these findings. The first patient had an iridotomy that was functioning and patent until regrowth of iris pigment epithelium 2½ years later. The second had closure of the iridotomy approximately 4 months postsurgery. In both cases, ultrasound biomicroscopy was able to demonstrate occlusion of the iridotomy solely at the iris pigment epithelial level with no filling of the stromal defect. In eyes with late closure of the iridotomy due to true iris pigment epithelial regrowth, the cells proliferate into the opening from the entire circumference of the iridotomy toward its center (Figure 3).
Clinical photograph demonstrating partial late closure of argon laser iridotomy by iris pigment epithelium with a small central patency (arrow) 3 years after iridotomy.
This study was supported in part by the Irving and Rena Katz Research Fund of the New York Glaucoma Research Institute, New York, NY.
Dr Teoh is currently affiliated with Tun Hussein Onn National Eye Hospital, Petaling Jaya, Selangor, Malaysia.
Reprints: Robert Ritch, MD, Glaucoma Service, Department of Ophthalmology, The New York Eye and Ear Infirmary, 310 E 14th St, New York, NY 10003 (e-mail: firstname.lastname@example.org).
Linda Oon-Cheng Teoh, Hiroshi Ishikawa, Jeffrey M. Liebmann, Robert Ritch. Late Closure of Argon Laser Iridotomies Following Regrowth of Iris Pigment Epithelium. Arch Ophthalmol. 2000;118(7):989–990. doi: