Quantitative analysis of iris changes following mydriasis in subjects with different mechanisms of angle closure.
Zhang Ye, Li Si Zhen, Li Lei, He Ming Guang, Thomas Ravi, Wang Ning Li
AI Summary
This study found iris area changes after dilation differ significantly among angle closure mechanisms; pupillary block eyes showed the least change, suggesting dynamic iris behavior is crucial in this type.
Abstract
Purpose
We estimate and compare change in iris cross-sectional area (IA) after physiologic and pharmacologic mydriasis in subjects with different dominant mechanisms for primary angle closure.
Methods
Anterior segment optical coherence tomography (AS-OCT) measurements in light, dark, and following pharmacologic dilation were obtained on primary angle closure suspects (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG) examined during the 5-year follow-up of the Handan Eye Study. Subjects were categorized into three subgroups according to their dominant angle closure (AC) mechanisms as determined by AS-OCT: pupillary block (PB), plateau iris configuration (PIC), and thick peripheral iris roll (TPIR). The IA and other biometric parameters measured using the Zhongshan Angle Assessment Program in the right eyes of all subjects were analyzed.
Results
A total of 364 right eyes of subjects with PACS (333), and PAC/PACG (31) was included in the analysis. Significant differences in the change of IAs (P = 0.030), IA loss per mm pupil diameter (PD) increase (P = 0.001) in light versus pharmacologic dilation, and IA loss per mm PD increase (P = 0.011) from dark versus pharmacologic dilation were observed among the three groups. The smallest decrease occurred in the PB group.
Conclusions
There are significant differences in IA and IA loss per mm of pupil change following physiologic or pharmacologic mydriasis in Chinese subjects with dissimilar dominant mechanisms for AC. Dynamic iris change may have a more important role in angle closure where PB is the dominant mechanism.
MeSH Terms
Shields Classification
Key Concepts5
In a cross-sectional study of 364 right eyes from Chinese subjects with primary angle closure suspects (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG), significant differences in the change of iris cross-sectional area (IA) (P = 0.030) were observed among subgroups categorized by dominant angle closure mechanisms (pupillary block, plateau iris configuration, and thick peripheral iris roll) when comparing light versus pharmacologic dilation.
In a cross-sectional study of 364 right eyes from Chinese subjects with primary angle closure suspects (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG), significant differences in iris cross-sectional area (IA) loss per mm pupil diameter (PD) increase (P = 0.001) were observed among subgroups categorized by dominant angle closure mechanisms (pupillary block, plateau iris configuration, and thick peripheral iris roll) when comparing light versus pharmacologic dilation.
In a cross-sectional study of 364 right eyes from Chinese subjects with primary angle closure suspects (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG), significant differences in iris cross-sectional area (IA) loss per mm pupil diameter (PD) increase (P = 0.011) were observed among subgroups categorized by dominant angle closure mechanisms (pupillary block, plateau iris configuration, and thick peripheral iris roll) when comparing dark versus pharmacologic dilation.
In a cross-sectional study of 364 right eyes from Chinese subjects with primary angle closure suspects (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG), the smallest decrease in iris cross-sectional area (IA) was observed in the pupillary block group among subgroups categorized by dominant angle closure mechanisms (pupillary block, plateau iris configuration, and thick peripheral iris roll).
Dynamic iris change may have a more important role in angle closure where pupillary block is the dominant mechanism in Chinese subjects with dissimilar dominant mechanisms for angle closure, based on a cross-sectional analysis of 364 right eyes.
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