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Brian J. Song, Max Forbes, Dana Blumberg, Ronald H. Silverman; Assessment of Anterior Segment Anatomy Using Anterior Segment Optical Coherence Tomography and Ultrasound Biomicroscopy Following Argon Laser Peripheral Iridoplasty. Invest. Ophthalmol. Vis. Sci. 2012;53(14):1996.
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© ARVO (1962-2015); The Authors (2016-present)
Argon laser peripheral iridoplasty (ALPI) is one of the few treatment modalities available for patients with persistent appositional closure following laser peripheral iridotomy who remain at risk of developing angle-closure glaucoma. However, there is limited data in the literature to quantify the changes that occur in the iridocorneal angle to support the efficacy of ALPI in these patients. The purpose of this study is to evaluate the changes that occur in the anterior segment using ultrasound biomicroscopy (UBM) and anterior segment optical coherence tomography (AS-OCT) after ALPI in patients with persistent appositional closure after laser peripheral iridotomy.
Three eyes of two patients with persistent narrow angles on gonioscopy following peripheral laser iridotomy were enrolled in this case series. Gonioscopy, AS-OCT, and UBM were performed in all cases before ALPI and one week after the procedure. Gonioscopy was graded from 0 to 4 according to the Schaffer grading system. AS-OCT was used to assess the anterior chamber, and UBM was used to image the ciliary sulcus. Anterior chamber depth, angle opening distance at 500 microns (AOD 500), ciliary sulcus conformation grade (grade 0 = absent, grade 1 = blunted, grade 2 = formed), and iris ciliary body contact length (ICB) were measured before and after ALPI. These metrics were graded, and the change in mean value was compared using a paired Student t-test. P-values < 0.05 were considered statistically significant.
Mean gonioscopic grade increased from 0.38 (prior to ALPI) to 1.38 following ALPI (p = 0.0027). There was no change in anterior chamber depth following ALPI. The mean change in AOD 500 was 64.5 microns (p = 0.056), while ciliary sulcus conformation grade increased from 0.16 to 0.57 following ALPI (p = 0.021). There was a slight decrease in ICB after ALPI (-18.67 microns), although this difference was not statistically significant (p = 0.592).
Changes in angle morphology can be effectively imaged and assessed quantitatively using AS-OCT and UBM. In addition, these imaging modalities can be used to track treatment efficacy following ALPI. Based on these findings, ALPI may be an effective treatment modality in patients with persistent appositional closure following laser peripheral iridotomy.
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