Purpose:
To establish the association of various anterior chamber parameters with angle configuration in an Asian population.
Methods:
Anterior segment optical coherence tomography (AS-OCT Carl Zeiss Meditec) was used to acquire anterior segment images of 123 subjects recruited from general ophthalmology and glaucoma clinics. AS-OCT images taken in the dark of the temporal angle of the right eye were analyzed. The fellow eye was used if the right eye had undergone previous laser or surgical procedure or if image quality was poor. Images were classified into one of four categories of angle configuration by 3 glaucoma specialists working independently: closed, very narrow, narrow and open. The Anterior Segment Analysis Program was used to quantify lens vault (LV), anterior chamber depth (ACD), area of recessed angle (ARA) and angle opening distance (AOD) in all images. Univariate and multivariate analyses were performed for all four parameters.
Results:
48 male and 75 female subjects, with a mean age of 64.4 years ± 10.1, were recruited. The number of subjects classified as having closed, very narrow, narrow and open angle were 44, 21, 37 and 21 respectively. Univariate analysis showed significant correlation between each parameter and angle configuration. Subjects classified with a closed angle configuration had significantly higher mean LV values, and significantly lower mean ACD, ARA and AOD values (p<0.01, one-way ANOVA).
Conclusions:
LV, ACD, ARA and AOD were found to be significantly associated with angle configuration in the study population. The presence of less overlap of mean values in AOD and ARA suggest that it may be possible to propose threshold values in AS-OCT imaging indicating likelihood of angle closure. Multivariate analysis was also performed (data not shown).
Keywords: anterior chamber • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • intraocular pressure