Anterior segment optical coherence tomography assessment of iris bombé before and after laser iridotomy in patients with uveitic secondary glaucoma

Editor, I ris bombé and acute pupillary block glaucoma are uncommon severe complications of uveitis (Moorthy et al. 1997). The success rate of laser iridotomy in patients with uveitic angle-closure glaucoma is disappointing (Forster et al. 1993; Spencer et al. 2001). Recently, anterior segment optical coherence tomography (AS-OCT) (Visante ; Carl Zeiss Meditec, Inc., Dublin, CA, USA) has been developed (Radhakrishnan et al. 2001; Nolan et al. 2007). Anterior segment OCT can show the anatomic structures of the AS, including iris thickness, anterior chamber depth and the extent of anterior iris bowing. With this information, we can choose the best site for iridotomy. In this way, AS-OCT will be a useful evaluation tool for minimizing complications and improving the success rate of iridotomy. Additionally, the non-contact and non-invasive AS-OCT system is suitable for use in the immediate preoperative period. In this report, we used AS-OCT to evaluate two cases of iris bombé. Case 1 concerned a 32-year-old man with Vogt)Koyanagi)Harada disease of 4 years’ duration, who was referred to our hospital. His best corrected visual acuity (BCVA) values were no light perception OD and 0.5 OS. Intraocular pressure (IOP) was 57 mmHg OD and 15 mmHg OS. Both eyes were injected with mutton fat keratic precipitates, 2+ anterior chamber cells, flare and extensive posterior synechiae. Methylprednisolone pulse therapy (500 mg ⁄day for 3 consecutive days) followed by prednisolone (30 mg ⁄day) was started. Although the inflammation subsided substantially after the pulse therapy, IOP in the left eye increased to 44 mmHg with totally occluded angle. Anterior segment OCT imaging showed marked iris elevation in the horizontal image and less elevation in the vertical section (Fig. 1). In this context, a superior iridotomy is not only less effective in relieving pupillary block, but is more likely to cause lens injury. Thus, combined argonYAG laser iridotomy was applied at the 2 o’clock position. Following iridotomy, the anterior chamber deepened (Fig. 2) and IOP decreased. At the last follow-up (6 months after iridotomy), BCVA was 1.2, IOP was 18 mmHg with topical timolol and the iridotomy was open. Case 2 concerned a 34-year-old woman who was referred for bilateral uveitis associated with ulcerative colitis. Her BCVA was 1.0 and IOP was 11 mmHg bilaterally. Slit-lamp examination revealed 2+ anterior chamber cells, flare and extensive posterior synechiae bilaterally. Despite medical therapy including topical dexamethasone and tropicamide, oral prednisolone and subconjunctival dexamethasone, progressive formation of posterior synechiae with consequent IOP elevation was observed in the right eye. Ten months after presentation, iris bombé with total angle closure was seen in the right eye (Fig. 3). The subject’s IOP was 34 mmHg despite maximal medication. Anterior segment OCT showed extensive peripheral iridocorneal contact in the horizontal and vertical sections (Fig. 3). Thus, combined argon-YAG laser iridotomy was applied in the mid-peripheral iris to avoid corneal endothelial damage. After iridotomy, the anterior chamber deepened and IOP decreased immediately (Fig. 4). At the last visit (6 months after iridotomy), the iridotomy remained patent and IOP was 16 mmHg without medication. Anterior chamber inflammation was controlled with infliximab (5 mg ⁄kg) started 2 months after iridotomy. In these cases, AS-OCT showed the anatomic structures of the AS, which was helpful for ensuring safe and successful laser iridotomy. Although the current material concerns only a small