TY - JOUR
T1 - Laser Peripheral Iridotomy in Eyes with Narrow Drainage Angles
T2 - Ultrasound Biomicroscopy Outcomes. The Liwan Eye Study
AU - He, Mingguang
AU - Friedman, David S.
AU - Ge, Jian
AU - Huang, Wenyong
AU - Jin, Chenjin
AU - Cai, Xiaoyu
AU - Khaw, Peng T.
AU - Foster, Paul J.
N1 - Funding Information:
Support. Dr He is recipient of a University College London (UCL) Graduate School Research Scholarship; UCL Overseas Research Scholarship (no. 2001061054); and grant from the Scientific and Technology Foundation of Guangdong Province, Guangzhou, China (no. 2005B30901008). Dr Foster receives support from the Medical Research Council, London, United Kingdom (grant no. G0401527); Wellcome Trust, London, United Kingdom (grant no. 075110); and Richard Desmond Charitable Foundation (via Fight for Sight), London, United Kingdom. Prof Khaw receives support from the Medical Research Council (grant no. G9330070); Moorfields Special Trustees, London, United Kingdom; and Michael and Isle Katz Foundation, London, United Kingdom. Dr Friedman is the Robert E. McCormick Scholar from Research to Prevent Blindness, New York, New York. Helen Keller International, New York, New York, provided logistical support and some equipment used
PY - 2007/8
Y1 - 2007/8
N2 - Purpose: To assess the short-term effect of laser peripheral iridotomy (LPI) on anterior segment anatomy in angle-closure suspects using ultrasound biomicroscopy (UBM). Design: Prospective intervention study. Participants: Persons identified as angle-closure suspects aged 50-79 years from a population-based survey in Guangzhou, China. Intervention: Laser peripheral iridotomy was performed on 1 randomly selected eye. Ultrasound biomicroscopy examination was carried out before and 2 weeks after the intervention. Main Outcome Measures: Proportion of eyes with iridotrabecular contact (ITC), as well as changes in UBM parameters including angle opening distance (AOD), iris thickness (IT), iris curvature, iris ciliary process distance, trabecular-ciliary process distance (TCPD), and scleral spur to iris insertion distance (SS-IR). Results: A total of 72 of 101 eligible subjects participated in the study. The proportion of people with UBM-identified ITC in ≥1 quadrant dropped from 95% (68/72) before to 59% (42/72) after LPI. After LPI, the mean AOD at 250 microns increased from 0.064 mm (standard deviation [SD], 0.052) to 0.085 (0.052) mm (P<0.001); angle recess area increased from 0.040 (0.030) to 0.070 (0.036) mm2 (P<0.0001); TCPD increased from 0.537 to 0.561 mm (P = 0.001); IT at 750 microns increased from 0.440 to 0.459 mm (P = 0.094), and IT at 1000 microns increased from 0.471 to 0.488 mm (P = 0.0001). Eyes whose angles remained closed after LPI (pigmented trabecular meshwork not visible in ≥3 quadrants) tended to have shallower AOD both at 250 (0.071 vs. 0.049 mm; P = 0.09) and 500 microns (0.108 vs. 0.052 mm; P = 0.001), a thicker iris (IT at 750 microns, 0.447 vs. 0.415 mm; P = 0.041), a more anterior positioned ciliary body (TCPD, 0.514 vs. 0.562 mm; P = 0.03), and a statistically nonsignificant more anterior iris insertion (SS-IR: 0.085 vs. 0.125 mm; P = 0.061), before LPI. Conclusions: Laser peripheral iridotomy results in a significant increase in the angle width in Chinese people with narrow angles. However, some iridotrabecular contact was found in 59% of eyes with a patent iridotomy. This was associated with smaller anterior chamber angle dimensions and a thicker iris, both of which may play a causative role in maintaining angle closure after LPI.
AB - Purpose: To assess the short-term effect of laser peripheral iridotomy (LPI) on anterior segment anatomy in angle-closure suspects using ultrasound biomicroscopy (UBM). Design: Prospective intervention study. Participants: Persons identified as angle-closure suspects aged 50-79 years from a population-based survey in Guangzhou, China. Intervention: Laser peripheral iridotomy was performed on 1 randomly selected eye. Ultrasound biomicroscopy examination was carried out before and 2 weeks after the intervention. Main Outcome Measures: Proportion of eyes with iridotrabecular contact (ITC), as well as changes in UBM parameters including angle opening distance (AOD), iris thickness (IT), iris curvature, iris ciliary process distance, trabecular-ciliary process distance (TCPD), and scleral spur to iris insertion distance (SS-IR). Results: A total of 72 of 101 eligible subjects participated in the study. The proportion of people with UBM-identified ITC in ≥1 quadrant dropped from 95% (68/72) before to 59% (42/72) after LPI. After LPI, the mean AOD at 250 microns increased from 0.064 mm (standard deviation [SD], 0.052) to 0.085 (0.052) mm (P<0.001); angle recess area increased from 0.040 (0.030) to 0.070 (0.036) mm2 (P<0.0001); TCPD increased from 0.537 to 0.561 mm (P = 0.001); IT at 750 microns increased from 0.440 to 0.459 mm (P = 0.094), and IT at 1000 microns increased from 0.471 to 0.488 mm (P = 0.0001). Eyes whose angles remained closed after LPI (pigmented trabecular meshwork not visible in ≥3 quadrants) tended to have shallower AOD both at 250 (0.071 vs. 0.049 mm; P = 0.09) and 500 microns (0.108 vs. 0.052 mm; P = 0.001), a thicker iris (IT at 750 microns, 0.447 vs. 0.415 mm; P = 0.041), a more anterior positioned ciliary body (TCPD, 0.514 vs. 0.562 mm; P = 0.03), and a statistically nonsignificant more anterior iris insertion (SS-IR: 0.085 vs. 0.125 mm; P = 0.061), before LPI. Conclusions: Laser peripheral iridotomy results in a significant increase in the angle width in Chinese people with narrow angles. However, some iridotrabecular contact was found in 59% of eyes with a patent iridotomy. This was associated with smaller anterior chamber angle dimensions and a thicker iris, both of which may play a causative role in maintaining angle closure after LPI.
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U2 - 10.1016/j.ophtha.2006.11.032
DO - 10.1016/j.ophtha.2006.11.032
M3 - Article
C2 - 17462739
AN - SCOPUS:34547151078
SN - 0161-6420
VL - 114
SP - 1513
EP - 1519
JO - Ophthalmology
JF - Ophthalmology
IS - 8
ER -