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Rajesh Sasikumar, Trupti Patil, Sathi Devi, Dhanraj Rao, Ramgopal Balu, Narendra Puttaiah, Bhujang Shetty; Changes in Anterior Segment Morphology after Laser Iridotomy in Asian Indian Eyes: A Source Swept Anterior Segment Optical Tomography Study. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4799.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate changes in anterior chamber parameters and factors that determine the extent of angle opening after laser peripheral iridotomy (LPI) in Asian Indian eyes with angle closure.
In this prospective, non-comparative cohort study, patients with angle closure disease who were scheduled for LPI were enrolled. Under standardized dark room conditions, anterior chamber parameters before and 1 week after LPI were compared using the source-swept anterior segment coherence tomography (Casia SS-1000 OCT; Tomey, Nagoya, Japan). Parameters measured using the built-in software included anterior chamber volume (ACV), iris volume (IV), anterior chamber depth (ACD), angle opening distance at 500 µm (AOD500) anterior to the scleral spur, trabecular-iris space area 500 (TISA500), and trabecular iris angle (TIA500). A scan biometry (Lens Star, Haag Streit, USA) was used to measure axial length (AL) and lens thickness (LT). Multivariate linear regression analysis was performed for predictors of percentage change in mean angle opening distance (AOD500).
Sixty six eyes (66 subjects) were analyzed; 8 eyes were excluded due to poor scleral spur visibility. The mean age was 57.9 ± 9.4 years; majority were women (57%). Post LPI, the mean angle width (modified Shaffer grading) increased from 1.03 (95% C.I, 0.83-1.23) to 2.83 (95% C.I, 2.54-3.11) (p<0.0001), with a corresponding increase in ACV from 104.7± 27.9 to 111.9 ± 24.0 mm3 (p<0.001); there was no change in ACD, LT or IV (p>0.5). While the TIA increased significantly in all quadrants (p<0.001), AOD500 increased only in the temporal and inferior quadrants. ARA500 increased only in the superior quadrant (P<0.01), while TISA showed significant changes in the nasal and inferior quadrants (p<0.001). While LT (β=-0.49, p=0.03) and ACD (β=0.60, p=0.005) were associated with ΔAOD500 in the univariate analysis, none of the parameters showed association in the multivariate analysis.
In this cohort of angle closure subjects, LPI caused a significant increase in the angle width in all quadrants. While ACV showed change after LPI, other variables did not show consistent change and there was no change in ACD or IV.
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