Anterior Segment Characteristics and Risk Factors for Primary Angle Closure Disease With Long Axial Lengths: The Handan Eye Study.

Purpose: To investigate the anterior segment characteristics of primary angle closure disease (PACD) with long axial length (AL) compared with that of those with short and medium AL and explore the risk factors associated with AC with different AL levels.

Methods: This observational cross-sectional study enrolled subjects aged 35 years or older who completed the follow-up examinations of the Handan Eye Study and dichotomized them into normal and PACD groups. Ocular data of the right eye were analyzed. AL was categorized into short (<22.0 mm), medium (22.0-24.0 mm), or long (>24.0 mm) subgroups. Demographic and anterior segment parameters of PACD subjects were compared between the three AL subgroups. Logistic regression analysis was performed to identify the risk factors for PACD in the three subgroups.

Results: Data from 715 PACD and 1446 normal subjects were analyzed. Only 6.6% of the PACD eyes had long AL, with lower spherical equivalent, larger anterior chamber depth (P < 0.001), and smaller lens thickness (P < 0.001) than those with short and medium AL. No significant differences were found for angle opening distance and iris parameters on comparing the values of eyes with long AL with that of those with short and medium AL. Significant risk factors for the development of PACD with long AL were peripheral iris thickness, anterior chamber width, and lens vault.

Conclusions: PACD with long AL was uncommon. A thicker peripheral iris, larger lens vault, and smaller ACW contributed to angle closure in these patients.