Morphologic features of iris in highly myopic eyes based on a novel swept-source optical coherence tomography.
Kang Ching, Meng Jiaqi, Wang Lan, Chen Chao, Chen Yuxi, He Wenwen, Zhang Keke, Lu Yi, Fang Yanwen, Zhu Xiangjia
AI Summary
Highly myopic eyes have larger iris volume and surface area, expanding coronally with axial length. This impacts anterior chamber angle configuration, relevant for glaucoma risk assessment.
Abstract
Background
To investigate the morphologic features of iris in the highly myopic (HM) eyes using a novel swept-source optical coherence tomography (SS-OCT).
Methods
In this retrospective case-control study, 100 eyes of 100 patients scheduled to have cataract surgery were included, categorized into the control (22 mm< AL < 24.5 mm) and HM (AL ≥ 26 mm) groups. Iris volume (IV), area of anterior iris surface (IS), area of posterior IS, and average iris thickness (IT), as well as anterior chamber volume (ACV) and trabecular-iris space at 500 µm (TISA 500) were evaluated using SS-OCT. The associated factors with morphologic features of iris were also investigated.
Results
The HM group showed significantly larger IV and area of anterior and posterior IS than the control group (all P < 0.001), while no difference was identified in IT between the groups. Similar trend in IV was seen in the superior and nasal segments, and area of anterior and posterior IS showed similar trends in all segments except the temporal segment. The IV, area of anterior and posterior IS were all positively correlated with AL (all P < 0.001). Multivariate linear regression revealed that a larger IV was associated with greater ACV. Both larger areas of anterior IS and posterior IS were associated with male, longer AL, greater ACV, and smaller TISA 500.
Conclusions
The HM eyes showed larger IV and area of IS than the control eyes, indicating a coronal expansion of the iris with AL. Iris morphology correlated with anterior chamber angle configuration.
MeSH Terms
Shields Classification
Key Concepts5
Highly myopic (HM) eyes (axial length ≥ 26 mm) showed significantly larger iris volume (IV) and area of anterior and posterior iris surface (IS) compared to control eyes (22 mm < axial length < 24.5 mm) in a retrospective case-control study of 100 eyes from 100 patients (all P < 0.001).
No significant difference was identified in average iris thickness (IT) between highly myopic (HM) eyes and control eyes in a retrospective case-control study of 100 eyes from 100 patients.
Iris volume (IV), area of anterior iris surface (IS), and posterior IS were all positively correlated with axial length (AL) in highly myopic (HM) eyes, as observed in a retrospective case-control study of 100 eyes from 100 patients (all P < 0.001).
Multivariate linear regression revealed that a larger iris volume (IV) was associated with greater anterior chamber volume (ACV) in highly myopic (HM) eyes, based on a retrospective case-control study of 100 eyes from 100 patients.
Both larger areas of anterior iris surface (IS) and posterior IS were associated with male gender, longer axial length (AL), greater anterior chamber volume (ACV), and smaller trabecular-iris space at 500 m (TISA 500) in highly myopic (HM) eyes, as determined by multivariate linear regression in a retrospective case-control study of 100 eyes from 100 patients.
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