TY - JOUR
T1 - Pupil dynamics in Chinese subjects with angle closure
AU - Zheng, Ce
AU - Cheung, Carol Y.
AU - Narayanaswamy, Arun
AU - Ong, Sim Heng
AU - Perera, Shamira A.
AU - Baskaran, Mani
AU - Chew, Paul T.
AU - Friedman, David S.
AU - Aung, Tin
N1 - Funding Information:
Grant support Grants from the National Medical Research Council, Singapore and the National Research Foundation, Singapore Financial disclosures Dr. T. Aung has received research funding, travel support and honoraria from Carl Zeiss Meditec.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/9
Y1 - 2012/9
N2 - Objective To evaluate the speed of pupil constriction (SPC) in response to a standardized change in illumination from dark to light using anterior segment optical coherence tomography (AS-OCT) in eyes with closed angles, compared to those with open angles. Methods This was a prospective, comparative, observational study. Study subjects with primary angle-closure glaucoma (PACG) and/or primary angle-closure (PAC) were recruited along with a group of normal as controls. Videos of iris and anterior segment changes in response to illumination were captured with real-time video recording from AS-OCT and analysed frame by frame, beginning from a dilated to a constricted pupil. Customized software was used to measure speed of iris constriction, anterior chamber depth (ACD), anterior chamber width (ACW), iris thickness, and pupil diameter (PD). SPC was defined as the rate of pupil diameter change in response to illumination. Results One hundred and sixty three Chinese subjects were recruited in this study. A total of 137 of 163 eligible videos (82.5%) were available for analysis, comprising 87 subjects with closed angles (all had undergone laser peripheral iridotomies before) and 50 with open angles. SPC was less in eyes with closed angles (1.22 mm/sec vs 1.56 mm/sec, p<0.001), after adjusting for age and ACW, and was positively correlated with axial length, ACD, anterior chamber angle status, PD in the dark, and iris thickness in the dark, (all r>0.2, all p<0.05). In multivariate analysis, SPC was independently associated with anterior chamber angle status (closed angle vs open angle) (β00.276, p00.016) and PD in dark (β0 0.129, p00.009), after adjusting for age, ACW, ACD, iris thickness and vertical cup-to-disc ratio. Conclusions Compared to those with open angles, eyes with closed angles in Chinese subjects have slower speed of pupil constriction in response to dark-light change, even after adjusting for biometric factors associated with angle closure. The results suggest that differences in irido-pupillary dynamics may play a role in the pathogenesis of angle closure.
AB - Objective To evaluate the speed of pupil constriction (SPC) in response to a standardized change in illumination from dark to light using anterior segment optical coherence tomography (AS-OCT) in eyes with closed angles, compared to those with open angles. Methods This was a prospective, comparative, observational study. Study subjects with primary angle-closure glaucoma (PACG) and/or primary angle-closure (PAC) were recruited along with a group of normal as controls. Videos of iris and anterior segment changes in response to illumination were captured with real-time video recording from AS-OCT and analysed frame by frame, beginning from a dilated to a constricted pupil. Customized software was used to measure speed of iris constriction, anterior chamber depth (ACD), anterior chamber width (ACW), iris thickness, and pupil diameter (PD). SPC was defined as the rate of pupil diameter change in response to illumination. Results One hundred and sixty three Chinese subjects were recruited in this study. A total of 137 of 163 eligible videos (82.5%) were available for analysis, comprising 87 subjects with closed angles (all had undergone laser peripheral iridotomies before) and 50 with open angles. SPC was less in eyes with closed angles (1.22 mm/sec vs 1.56 mm/sec, p<0.001), after adjusting for age and ACW, and was positively correlated with axial length, ACD, anterior chamber angle status, PD in the dark, and iris thickness in the dark, (all r>0.2, all p<0.05). In multivariate analysis, SPC was independently associated with anterior chamber angle status (closed angle vs open angle) (β00.276, p00.016) and PD in dark (β0 0.129, p00.009), after adjusting for age, ACW, ACD, iris thickness and vertical cup-to-disc ratio. Conclusions Compared to those with open angles, eyes with closed angles in Chinese subjects have slower speed of pupil constriction in response to dark-light change, even after adjusting for biometric factors associated with angle closure. The results suggest that differences in irido-pupillary dynamics may play a role in the pathogenesis of angle closure.
KW - Anterior segment optical coherence tomography
KW - Closed angles
KW - Speed of iris constriction
UR - http://www.scopus.com/inward/record.url?scp=84866551511&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84866551511&partnerID=8YFLogxK
U2 - 10.1007/s00417-012-1934-7
DO - 10.1007/s00417-012-1934-7
M3 - Article
C2 - 22290071
AN - SCOPUS:84866551511
SN - 0721-832X
VL - 250
SP - 1353
EP - 1359
JO - Albrecht von Graefes Archiv für Klinische und Experimentelle Ophthalmologie
JF - Albrecht von Graefes Archiv für Klinische und Experimentelle Ophthalmologie
IS - 9
ER -