Pigment dispersion secondary to anterior chamber angle recession

Abstract

Dear Editor: Irido-zonular and/or -lenticular disruption, mostly due to posterior bowing of the iris, is believed to be the mechanism of primary pigment dispersion syndrome (PDS). Characteristic findings of PDS include Krukenberg spindle, homogenous trabecular meshwork (TM) pigmentation, and spoke-like mid-peripheral iris transillumination defects [1–5]. Primary PDS usually affects bilateral eyes, although the morbidity and manifestations may be asymmetric. Herein, we report an unusual case of monocular pigment dispersion secondary to traumatic anterior chamber angle recession. A 33-year-old male complained of blurred vision and distending pain in his right eye for more than 1 year. He sustained blunt ocular trauma by a wooden stick 10 years prior. He had no family history of either glaucoma or PDS. On admission, his visual acuity was 20/200 OD and 20/20 OS. A Krukenberg spindle was discerned in his right eye (Fig. 1a), along with posterior bowing of the mid-peripheral iris. A Zentmayer ring was visualized on the rear surface of the crystalline lens. Homogenous heavy TM pigmentation and 270o of anterior chamber (AC) angle recession were revealed on gonioscopy (Fig. 1b). Spoke-like iris transillumination defects were not seen. His left eye was unremarkable on both biomicroscopy and gonioscopy, with minimal TM pigmentation and flat iris configuration (Fig. 1c). The vertical cup/disc ratio was 0.9 OD and 0.3 OS. The intraocular pressure (IOP) was 52 OD and 17 OS. Refraction revealed −0.25 diopters in both eyes. Humphrey visual field analysis showed inferior arcuate scotoma in the right eye and normal field in the left. Ultrasound biomicroscopy (UBM) revealed posterior bowing of the iris and irido-zonular and -lenticular contact in the right eye (Fig. 1d), and flat iris in the left. The patient underwent trabeculectomy for pigmentary glaucoma in his right eye, with postoperative IOP in the teens during 6 years of follow-up. The iris became flat, and no more pigment dispersion was discerned after the surgery. Visual field deterioration was not detected with Humphrey visual field analysis postoperatively. The left eye did not show any signs of pigment dispersion or other ocular disorders after 6 years of surveillance. Pigment dispersion may occur after ocular trauma, intraocular lens implantation, iritis, and so on [1, 4, 6]. However, such secondary pigment dispersion differs from primary PDS, in that the former usually does not have Krukenberg spindle and iris transillumination defects. Krukenberg spindle is more likely to be the result of continuous pigment shedding like primary PDS, which is secondary to irido-zonular contact. The typical appearance This manuscript has not been published or submitted for publication elsewhere. We certify that all applicable institutional and governmental regulations concerning the ethical use of human subjects were followed during this research. The authors have full control of the primary data, and they agree to allow Graefe’s Archive for Clinical and Experimental Ophthalmology to review their data if requested.